Abstracts from the 2025 AMSA Reciprocal Meat Conference

1 Impact of Captive Bolt Placement on Tissue Dimensions of Heads from Bos Taurus Beef Cows Older Than 30 Months of Age

Allison L. Matzek^1,*, Ruth Woiwode^2,3, Emma M. Hamilton², Ashlynn A. Kirk², Maryn J. Cowell^2,4, Perle E. Zhitnitskiy², Kurt D. Vogel², and Karly N. Anderson², ¹University of Nebraska–Lincoln, Lincoln, NE 68588, USA, ²University of Wisconsin - River Falls, River Falls, WI 54022, USA, ³Colorado State University, Fort Collins, CO 80523, USA, ⁴University of Minnesota, St. Paul, MN 55455, USA *allison.matzek@my.uwrf.edu

Introduction/Objectives: All conventionally slaughtered animals must be rendered insensible with a single stun prior to the commencement of slaughter procedures to comply with US federal regulations and to uphold the welfare of animals by preventing pain and distress. Penetrating captive bolt (PCB) is an approved method of euthanasia and preslaughter stunning for beef cows. Industry guidelines currently include multiple recommended PCB placements with limited scientific evaluation. The objectives of this study were to determine tissue depth, location of the PCB placement in relation to anatomical features, and potential for brain contact at the FRONTAL (intersection of 2 lines from the lateral canthus to the opposite poll), IDEAL (placement determined based on the location of the thalamus), and POLL (just below the external occipital protuberance at the midline, directed toward the central incisors) placements for mature beef cows.

Materials and Methods: Cadaver heads were obtained from 21 Bos taurus beef cows older than 30 mo of age stunned with a pneumatic PCB at a frontal placement. The heads were chilled before data collection. External head measurements (nose to placement [mm], placement to poll [mm], eyes to placement [mm], and placement to FRONTAL [mm]) were obtained with a digital caliper before a Jarvis 0.25R Super Heavy Duty PCB with 6GR cartridges was applied at the POLL. No additional shots at the FRONTAL placement were applied. Following the PCB application, heads were split at the midline, and tissue depth was measured at the FRONTAL and POLL placements with a digital caliper. Images of each head were obtained to determine an IDEAL placement that would consistently target the thalamus. Tissue depths at the IDEAL placement were measured using the images taken of each head. Mean separation was determined via Student t-tests with the Bonferroni–Holm adjustment. Upper reference limits (URL) were determined for tissue depths to estimate the bolt length required to reach the brain and thalamus for the majority of beef cows older than 30 mo of age.

Results: All results are reported as mean plus or minus SD. URL are also reported for tissue depths. Total tissue thickness was greatest (P < .0315) at the POLL placement (34.62 ± 1.23 mm; URL: 42.63 mm) followed by the IDEAL (28.74 ± 1.50 mm; URL: 46.00 mm) and FRONTAL (23.60 ± 1.23 mm; URL: 35.42 mm) placements. The depth to thalamus was measured at the IDEAL and POLL placements. The thalamic depth was greater (P = .0100) at the POLL (97.40 ± 2.37 mm; URL: 119.31 mm) than the IDEAL (88.10 ± 2.37 mm; URL: 101.59 mm) placement. External head measurements were reported for the FRONTAL and IDEAL placements to compare their location relative to anatomical landmarks. There was no evidence to support a difference (P = .6118) between the distance from eyes to placement between the FRONTAL (9.67 ± 0.35 mm) and IDEAL (7.61 ± 0.30 mm) placements. The nose to placement distance was greater (P < .0001) at the FRONTAL placement (43.76 ± 0.46 mm) than the IDEAL placement (27.33 ± 0.54 mm), and the distance from poll to placement was greater (P < 0.0001) at the IDEAL placement (25.13 ± 0.43 mm) than the FRONTAL placement (9.67 ± 0.35 mm). The IDEAL placement is located 0.18 plus or minus 0.22 mm on average below the FRONTAL placement but did not significantly differ (P = .5333) in location from the FRONTAL placement.

Conclusion: These data suggest that a shot placed slightly below the recommended FRONTAL placement may be a possibility for PCB use for euthanasia and preslaughter stunning in beef cows older than 30 mo of age. The FRONTAL placement is acceptable to use for preslaughter stunning and euthanasia in beef cows and was not located in a different location than the IDEAL placement used in this study. Additionally, the POLL placement could be an alternative placement to use for beef cows and requires further investigation.

Funding Source: This work was supported by the Agriculture and Food Research Initiative competitive award no. 2022-67016-36344 from the US Department of Agriculture’s National Institute of Food and Agriculture.

Keywords: cattle, captive bolt, stunning, welfare.

2 Relationship of Tissue Dimensions and Stun Placement on Cadaver Heads From 2-to-3-Year-Old Male Bison (Bison Bison)

Allison L. Matzek^1,*, Emma M. Hamilton¹, Ashlynn A. Kirk¹, Denise L. Perry^1,2, Kurt D. Vogel¹, and Karly N. Anderson¹, ¹University of Wisconsin - River Falls, River Falls, WI 54022, USA, ²Single Shot Consulting, LLC, Hampton, MN, USA ^*allison.matzek@my.uwrf.edu

Introduction/Objectives: The bison industry in the United States has been growing rapidly. In 2023, over 75,000 bison were commercially slaughtered, but stunning methods for bison did not appear to be scientifically evaluated at the time of our study. Our primary objective was to evaluate tissue thicknesses at the FRONTAL (2.5 cm above a line connecting the bottom of the horns) and POLL (below the crest of the head at the midline and angled toward the ventral aspect of the nose) placements in bison. Our secondary objectives were to assess potential for bolt-thalamus contact, determine an optimal stunning placement based on thalamic location, and determine the relationship between external head characteristics and tissue depths.

Materials and Methods: Fifteen cadaver heads from 2-to-3-y-old bulls (hot-carcass weight: 300.50 ± 27.42 kg; mean ± SD) with hide-on were obtained from a commercial slaughter establishment after being stunned with a 0.410-bore shotgun at a frontal location. All heads were shaved, and external head features were measured. A 0.25R-caliber Jarvis free-flight penetrating captive bolt (PCB) was applied at the POLL placement. No PCB placements were made at the FRONTAL placement. Heads were split at the midline, and soft tissue and cranial thicknesses were measured with a digital caliper. Tissue depth measurements were taken from shaved heads and therefore did not account for the amount of hair the bolt would need to travel through. Digital images were obtained of the split head to evaluate brain and thalamic contact plane. From these images, an IDEAL (placement determined based on the location of the thalamus) placement was determined to ensure bolt-thalamic contact.

Results: The IDEAL placement was in a significantly different (P < .001) location than the FRONTAL placement and was located 8.33 cm plus or minus 0.36 cm above the base of the horns at the midline with the shot placed perpendicular to the surface of the head. The bolt path was in the plane of the brain for the FRONTAL and POLL placements for 15 of 15 heads (100.0%; 95% CI, 78.2% to 100.0%), and for the IDEAL placement, in the plane of the brain for 14 of 14 heads (100.0%; 95% CI, 76.8% to 100.0%). Because the IDEAL placement was determined based on the location of the thalamus, the thalamus had to be completely visible to assign an IDEAL placement, and for 1 of the heads it was not possible to determine an IDEAL placement. For the IDEAL placement, the bolt path was in the plane of the thalamus for 14 out of 14 heads (100.00%; 95% CI, 76.8% to 100.0%), while only in the plane of the thalamus at the FRONTAL placement for 11 out of 14 heads (78.57%; 95% CI, 49.2% to 95.3%), and at the POLL placement for 10 out of 14 heads (71.43%; 95% CI, 42.0% to 91.6%). Total tissue thickness was significantly greater (P < .0008) at the FRONTAL placement (75.00 ± 1.84 mm; URL: 89.31 mm) than the IDEAL (60.92 ± 1.90 mm; URL: 70.64 mm) and POLL (64.60 ± 1.84 mm; URL: 85.52 mm) placements. There was no evidence to support a difference (P = .5166) in total tissue thicknesses between the IDEAL and POLL placements. Thalamic depth at the IDEAL placement was 115.27 mm plus or minus 8.36 mm (URL: 133.96 mm).

Conclusion: This study quantified tissue thicknesses of 2-to-3-y-old male bison at the FRONTAL and POLL placements. Quantifying tissue thicknesses in bison at different shot placements helps to compare the placements and ensure that all bison are successfully rendered insensible with a single stun. Understanding the total tissue thicknesses and thalamic depth for bison also allows for the selection and manufacture of suitable PCB for stunning. The IDEAL placement was found to be the most direct path to the thalamus with the least tissue thickness and requires a minimum bolt penetration depth of 133.96 mm for 2-to-3-y-old male bison to maximize the potential for bolt-thalamic contact. It is likely that an intact hair coat will require greater penetration depth to make direct bolt contact with the thalamus. Future studies should evaluate the efficacy of the IDEAL placement in live bison and assess the PCB length required to successfully stun at this placement.

Funding Source: This research was funded by the University of Wisconsin - River Falls’s Falcon Scholars Program and Humane Handling Institute.

Keywords: bison, captive bolt, stunning welfare.

3 Relationship Between Captive Bolt Placement, Tissue Parameters, and Potential for Thalamic Contact in Cadaver Heads From 4-to-20 Year-Old Bison Cows (Bison Bison)

Kendrick R. Otto^1,*, Emma M. Hamilton^1,2, Ashlynn A. Kirk¹, Charles Bildstein³, Kurt D. Vogel¹, and Karly N. Anderson¹, ¹University of Wisconsin - River Falls, River Falls, WI 54022, USA, ²Colorado State University, Fort Collins, CO 80523, USA, ³Bunzl Processor Division, Riverside, MO 64150, USA *kendrick.otto@my.uwrf.edu

Introduction/Objectives: The National Bison Association reported that approximately 75,000 bison were harvested under federal inspection in 2023. Bison are most often stunned with a firearm, which imposes risk because a firearm produces a flying object that may miss the target and result in a failed stun, strike bystanders, or introduce physical hazards to the muscles of the neck and chuck. Penetrating captive bolts (PCB) are a safer option, but commercial PCB may not have the proper bolt length to successfully reach the thalamus, a brain structure implicated in consciousness. To the best of our knowledge, this was the first study to evaluate stun placement for bison cows. The primary objective of this study was to compare tissue thicknesses, thalamic depth, and potential for brain and thalamic contact at 3 PCB placements (FRONTAL, IDEAL, POLL). The secondary objective was to understand the relationship between the FRONTAL and IDEAL placements and anatomical head features.

Materials and Methods: Seventy-two hide-on cadaver heads from 4-to-20-y-old bison cows (hot-carcass weight: 297.23 ± 106.23 kg, mean ± SD) were obtained from a commercial slaughter establishment after the source animals were stunned at a frontal location with a 0.410 bore shotgun. Heads were transported to the University of Wisconsin - River Falls and stored in a walk-in cooler for approximately 121.5 h after arrival. Each head was shaved, and external head measurements were collected with a digital caliper. Heads were randomly assigned to 1 of 3 PCB placements: FRONTAL, 2.5 cm above the base of the horns; IDEAL, 8.3 cm above the base of the horns; and POLL, backside of the poll, with the PCB directed toward the ventral aspect of the nose. Each stun treatment was applied with a prototype 0.25R-caliber free-flight PCB with 38.1 mm greater bolt travel distance than other commercially available handheld PCB. Six grain cartridges were used in the PCB. The length of the head was collected by measuring the distance from the tip of the nose to the poll with a digital caliper. The distance between the poll and the FRONTAL and IDEAL placements was also measured. Each head was split on center with a band saw to expose the bolt path. Measurements of soft tissue and cranial thickness were collected at the site of captive bolt application with a digital caliper. After splitting, a digital image was collected of each half of each head with pins placed at the levels of the eyes and horns, along with a 15-cm ruler on the surface of the head. The camera was set 50.8 cm above each head. These images were used to assess potential for brain contact. Upper reference limits (URL) were determined for total tissue thickness to estimate the bolt travel distance required to reach the brain for 97.5% of bison cows 4-to-20 y of age.

Results: All results are reported as mean ± SD, and URL are also reported for total tissue thickness. There was no evidence to support a difference (P > .2206) in head weight between the FRONTAL (18.9 ± 0.58 kg), IDEAL (19.5 ± 0.46 kg), and POLL placements (18.44 ± 0.36 kg). There was also no evidence to support a difference (P > .8760) in overall head length, indicated by the distance from the poll to the nose between the FRONTAL (53.98 ± 0.50 cm), IDEAL (54.38 ± 0.34 cm), and POLL placements (54.60 ± 0.30 cm). The distance from the poll to PCB placement was also recorded for the FRONTAL (12.39 ± 0.33 cm) and IDEAL placements (8.04 ± 0.31 cm); however, comparisons could not be made because this measurement was not normally distributed for the FRONTAL placement. Soft tissue thickness was greater (P < .0026) at the POLL placement (16.05 ± 1.61 mm) than the IDEAL (9.93 ± 0.41 mm) and FRONTAL (9.00 ± 0.36 mm) placements; however, there was no evidence to support a difference (P = .2820) in soft tissue thickness between the IDEAL and FRONTAL placements. Cranial thickness was greater (P = .0002) at the IDEAL placement (34.07 ± 1.32 mm) than the POLL placement (25.77 ± 1.36 mm). Comparisons of cranial thickness including the FRONTAL placement (28.13 ± 0.96 mm) could not be made, as cranial thickness at the FRONTAL placement was not normally distributed. The total tissue thickness was greater (P = .0013) at the IDEAL placement (43.96 ± 1.68 mm; URL: 57.45 mm) than the FRONTAL placement (37.16 ± 1.02 mm; URL: 46.96 mm). However, there was no evidence to support a difference (P > .108) in total tissue thickness between the FRONTAL and POLL placement (41.51 ± 1.68 mm; URL: 58.93 mm) or between the IDEAL and POLL placement. The brain was located within the plane of bolt travel for all heads at each placement (FRONTAL: 25/25; IDEAL: 23/23; POLL: 26/26).

Conclusion: Per the manufacturer, the expected bolt travel distance of the PCB used in this study was 152.4 mm, which is estimated to be 38.1 mm longer than any commercially available PCB device. This expected bolt travel distance is greater than any of the URL values for total tissue thickness determined in the present study for the FRONTAL, IDEAL, and POLL placements, suggesting that this prototype PCB should reach the brain for at least 97.5% of bison cows aged 4-to-20 y. Additionally, the brain was located within the bolt path for all heads at each PCB placement, suggesting that each placement may be appropriate for use with this device.

Funding Source: This project was funded by the University of Wisconsin - River Falls’s Research, Scholarly, and Creative Activity Program and the Humane Handling Institute.

Keywords: bison, captive bolt, stunning, welfare.

4 Hey Good Looking, How Have You Been Cooking? The Role of Cooking Method on Cooked Color and Palatability

Greta E. Huber^*, Samuel F. Stickley, Taylor M. Dieball, Chesney A. Effling, Lauren M. Frink, Mason J. Prester, Sidney A. Munk, Stephanie L. Witberler, Michael D. Chao, Morgan D. Zumbaugh, Jessie L. Vipham, Travis G. O’Quinn, and Erin S. Beyer, Kansas State University, Manhattan, KS 66506, USA *gretahuber@ksu.edu

Introduction/Objectives: Cooking method and degree of doneness (DOD) are crucial in determining beef palatability, affecting key sensory attributes such as juiciness, tenderness, flavor, and color. While various cooking methods are commonly used to prepare beef, their impact on palatability and appearance at different DOD remains a point of interest. Consumers often use both internal and external color to visually assess the steak’s doneness, which can influence their expectations and overall eating experience. Therefore, the goal of this study was to determine the palatability and appearance differences between 6 cooking methods and 2 DOD.

Materials and Methods: Paired beef striploins (N = 12) were collected at a commercial beef processing plant and transported to Kansas State University. Striploins were denuded into the Longissimus lumborum and sliced into 2.5-cm steaks. Steaks were randomly assigned one of 6 cooking methods (sous vide, oven, grill, flat top, clamshell, or air fryer) and a DOD (medium rare [MR] or well done [WD]). Steaks were aged for 21 d at 4°C in the absence of light, then frozen at −40°C until use. Prior to cooking, steaks were thawed for 24 h at 2°C to 4°C. Air fryer steaks were cooked at 204°C and monitored using a Type K Thermaworks probe. Steaks were flipped at 32°C (MR) or 46°C (WD) and removed at 58°C (MR) or 74°C (WD). Oven and grill steaks were cooked at 177°C, flipped at 29°C (MR) or 35°C (WD), and removed at 58°C (MR) or 75°C (WD). Flat top, clamshell, and grill steaks were also cooked at 177°C and monitored with a Thermapen. Flat-top steaks were flipped at 29°C (MR) or 32°C (WD) and removed at 57°C (MR) or 74°C (WD). Clamshell steaks were cooked to 57°C (MR) or 74°C (WD). Sous-vide steaks were cooked in vacuum-sealed bags at 57°C (MR) or 68°C (WD) for 1 h, then seared on the flat top (177°C) for 30 s per side, and removed at 60°C (MR) or 75°C (WD). Endpoint temperatures for all cooking methods were monitored with Thermapens inserted into the geometric center of each steak and targeted at 62.8°C for MR and 76.7°C for WD. Consumers (N = 96 per DOD; N = 192 total) evaluated 6 samples (1 per cooking method within each DOD) using a 100-point line scale anchored at 0 and 100 for juiciness, tenderness, flavor, overall liking, and overall appearance. Acceptability (acceptable/unacceptable) was determined for each trait. Consumers were asked about the visual expectations by determining (yes/no) if the steak’s appearance matched the expected DOD. Data were analyzed using SAS PROC GLIMMIX using a split-plot design, with cooking method as a whole-plot factor and DOD as the subplot factor. α was set at 0.05.

Results: The consumers determined the oven steaks were juicier (P < .05) than the flat top, air fryer, sous-vide, and grill steaks, while being rated similar (P > .05) for juiciness compared to clamshell. Similarly, oven samples were rated the most tender (P < .05) compared to all other cooking methods. There was an interaction (P < .05) between cooking method and DOD for flavor liking. The MR grill steaks had a higher (P < .05) flavor rating compared to all cooking methods within the WD DOD, as well as the MR sous-vide and clamshell steaks. Within each cooking method, aside from the flat top, consumers rated the MR samples higher for flavor liking (P < .05) compared to the WD samples. The flat-top samples were rated similarly (P > .05) between the MR and WD DOD. Although consumers found differences (P < .05) in juiciness, tenderness, and flavor liking among the cooking methods, these did not (P > .05) illicit an impact on the overall liking scores. Consumers rated the highest (P < .05) percentage of steaks from the oven and clamshell as acceptable for juiciness. Similar to the overall liking results, the percentage of consumers that rated samples as acceptable for the remaining traits were similar (P > .05) among cooking methods. DOD influenced all sensory attributes evaluated by consumers (P < .05). As expected, the MR steaks were rated higher (P < .05) than WD steaks for all traits: juiciness, tenderness, flavor, overall liking, and overall appearance. Subsequently, the percentage of consumers that rated each sample as acceptable for all traits (juiciness, tenderness, flavor, overall liking, and overall appearance) was higher (P < .05) in the MR samples than the WD. This study aimed to understand the impact of cooking method on appearance rating and acceptability. Oven and flat-top steaks had a higher (P < .05) overall appearance rating compared to the clamshell, sous-vide, and sir fryer steaks, while being similar (P > .05) to the grill. However, there was an interaction (P < .05) for the visual expectation of the steaks when consumers were asked if it met their criteria for a MR or WD DOD. WD air fryer steaks resulted in a higher (P < .05) percentage of consumers who determined it met their visual expectations compared to all treatment and DOD combinations, aside from (P > .05) the sous vide cooked to a WD DOD.

Conclusion: Although consumers perceived juiciness, tenderness, flavor, and overall appearance differently for some cooking methods, the cooking method had no impact on overall liking. While the MR DOD rated higher than the WD DOD for almost all sensory traits, consumers found no difference between the 2 DOD for flavor liking scores within the flat-top steaks. Most interestingly, consumers determined differences in appearance within each DOD, indicating that while each cooking method resulted in similar endpoint temperatures, the cooking method impacted internal and external color, influencing the consumer’s preference. This was supported by the interaction between DOD and cooking method for visual expectations where consumers determined that both DOD and cooking method influenced the visual DOD. While this project identified a relationship between cooking method, DOD, and consumer preferences, the cooked color attributes must be explored to understand the comprehensive implications for the consumer and food service industry.

Funding Source: Kansas State University.

Keywords: beef, consumer, cooking method, degree of doneness.

5 Performance, Serum, Hematology Parameters, Muscle Evaluation, Lipid Profile, and Thiobarbituric Acid Reactive Substances of Pig Fed Saturated Fat: Red Meat, Cheese, and Egg

Patience Fakolade^*, Plebian Aluko, Oluwatosin Adedire, Janet ILori, Ruth Ogunniyi, Blessinh Awotola, Solomon Abokede, and Oliyide Adisa, Osun State University, Osogbo, Osun State, Nigeria *patience.fakolade@uniosun.edu.ng

Introduction/Objectives: Controversy on the negative effect of consumption of saturated fat on human health is the focus of this study. Nowadays food is not intended to only satisfy hunger in the form of carbohydrates but to prevent nutritional related diseases, stay much longer in the stomach, build up muscle, and improve the physical and mental wellbeing of consumers. There is discouragement in the consumption of animal products (e.g., eggs, milk, and red meat) because of their saturated fat, with the belief that they cause chronic diseases such as diabetes, arthritics, heart disease, cancer, and cardiovascular diseases. For these reasons, people decide to cut back on animal products (e.g., protein and fat) by increasing the intake of vegetable oils and carbohydrates. Experimenting with the effects of saturated fat from pigs fed saturated fat could retard this believe.

Materials and Methods: Seven treatments consisting of T1, boiled red (beef); T2, fried red meat (beef); T3, boiled eggs; T4, fried eggs; T5, boiled cheese; T6, fried cheese; and T7 concentrate grower mash (control), all with saturated fat content, were fed to 35 grower large white male pigs for 8 wk. Their performance, muscle and blood evaluation, cholesterol content, and lipid profile were determined in a completely randomized design. The initial weights of the pigs were taken before allocating them into treatments, and, thereafter, parameters like daily feed intake, final body weight, body weight gain, daily feed intake, and feed conversion ratio were evaluated. A digestibility study was conducted during the last week of the experiment. Three pigs were selected randomly per treatment and kept in a metabolic cage for digestibility studies. Fecal samples were collected daily, oven dried, and taken to the laboratory for proximate composition to determine the nutrient composition in the feed according to the AOAC (1990). Blood samples were collected from the jugular vein using syringes for the hematologic and serum biochemical analysis by 6.00 AM and taken to the laboratory using an ice container pack. Ethylene diamine tetra acetic acid test tubes, as anticoagulant, were used to collect blood samples for evaluation. Muscle evaluation, cholesterol content, lipid profile, and thiobarbituric acid reactive substances were evaluated according to Roschlau et al. (2014), proximate composition according to AOAC (2005), and physicochemical analysis and palatability score according to Fakolade et al. (2018). All data collected were subjected to a 1-way analysis of variance using the statistical package SPSS version 20, and the significant difference in the mean was compared using Tukey honestly significant different multiple range test in a complete randomized design.

Results: T7 had highest (P < .05) in final weight gain of 20.50 g, body weight gain of 8.00 g, and daily weight gain of 0.16 g than other treatments evaluated. Feed conversion ratio was higher in T3 and T4 (boiled and fried egg) (P < .05) and lowest significantly in T5 and T6 (boiled and fried cheese), respectively. Hematology parameters had lowest packed cell volume (PCV), hemoglobin (Hb), red blood cell count (RBC), white blood cell count (WBC), and platelet count in T1 than for other treatments. For protein content, ash and ether extract were lower significantly (P < .05) in T7 but higher in T1 (boiled egg). Cholesterol values had no significant differences (P > .05) for all the treatments evaluated. In T7, low-density lipoprotein was significantly higher for both blood and muscle samples and lowest in high-density lipoprotein. This study indicated that consumption of saturated fat fed to pigs did not increase the level of cholesterol, gave lower low-density lipoprotein and higher high-density lipoprotein with positive effects in muscle protein and ash content, PCV, Hb, RBC, WBC, and platelet count to pig health.

Conclusion: Consumption of saturated fat (red meat, egg, and cheese) had no detrimental effects on pigs that consumed them. Instead, the hematology, serum parameters, and lipid profile shows positive effects with moderate weight gains. Further research is needed to determine if consumption of animal products to increase protein intake will translate similarly to humans to improve human health as with the assumption that it could cause certain chronic diseases. Animal product consumption should be encouraged to all age groups so as to increase that total protein intake in human diet.

Figure 1.

Serum biochemistry of pig fed saturated fat in their diet.

Keywords: saturated fat, red meat, egg, milk, cheese.

6 A Fresh Look at Ground Beef Spoilage: Determining Spoilage Thresholds for Ground Beef Using Microbial Analysis and Consumer Evaluation

Lauren M. Frink^*, Stephanie L. Witberler, Mason J. Prester, Chesney A. Effling, Erin S. Beyer, Jessie L. Vipham, Morgan D. Zumbaugh, Michael D. Chao, and Travis G. O’Quinn, Kansas State University, Manhattan, KS 66506, USA *lfrink@ksu.edu

Introduction/Objectives: The spoilage of red meat has been extensively studied, with a focus on microbial growth and objective color measurements. Previous studies have also evaluated the correlation between microbial growth and objective measurements, reporting that meat is considered spoiled when bacterial levels reach 7 Log CFU. However, spoilage is evaluated by the consumer using organoleptic traits such as sight, touch, smell, and taste. Therefore, the objective of this study was to determine the point at which consumers perceive ground beef as spoiled based on appearance, texture, odor, and taste and to compare these perceptions with microbiological measurements and the meat microbiome.

Materials and Methods: This study utilized 454 g ground beef (80% lean) packages (N = 128) obtained from a commercial case-ready facility. Samples were shipped and stored in the absence of light at 2°C to 4°C in trigas-flushed mother bags. Paired ground beef packages were randomly designated display dates (0, 2, 4, 6, 8, 10, 12, and 14d). One sample from each pair was utilized for consumer sensory evaluation, while the other was analyzed for microbial enumeration and microbiome analysis. Consumers (N = 128/panel type) evaluated the appearance of the samples in the retail case as well as the touch, odor, and taste of the samples. For all sensory evaluations, each consumer evaluated 8 samples, 1 from each day of display in a random order. Consumers evaluated the desirability of all organoleptic measurements on a continuous 100-point line scale for desirability. Additionally, consumers were asked a yes/no question if they would purchase the package and a yes/no question if they would consider the sample as spoiled based upon each sensory trait. Microbial enumeration was conducted using aerobic plate counts (APC), Enterobacteriaceae (EB), and E. coli counts (ECC). 25 g samples of ground beef were stomached with 225 mL of peptone water to produce serial dilutions. One-mL aliquots of the dilutions were plated on the APC, EB, and ECC Petrifilms and then incubated and counted per the manufacturer’s guidelines. To evaluate the microbiome, DNA samples were isolated from each ground beef sample using the Qiagen DNeasy Mericon Food standard protocol. The DNA concentration of each sample was quantified using the high sensitivity double strand DNA kit and the Qubit 2.0 fluorometer. Samples were analyzed at Novogene Co., and the effects of day of display were analyzed using R. Sensory data, analyzed in SAS for “would purchase” and “spoiled” responses, and analyzed as a completely random design with day of display as the fixed effect with an a of 0.05.

Results: Consumer ratings for “spoiled” and “would purchase” were generated for organoleptic traits. Appearance models showed the most significant change, with 88.6% of samples rated as “would purchase” and 3.1% of samples as “spoiled” on day 4. Purchase intent was lower (P < .05) (6.8%) and “spoiled” samples were higher (81.3%; P < .05) on day 8. According to touch and odor, there was a steady increase (P < .05) across the display period for samples rated as “spoiled,” with day 14 having the highest (P < .05) spoilage rating. The inverse was observed for purchase intent based upon touch and odor, with day 0 having the highest (P < .05) purchase intent and day 14 having the lowest (P < .05). There was no difference (P > .05) in purchase intent based upon the taste across the display period. Consumers reported a difference (P < .05) in spoilage rating for taste; however, the highest (P < .05) average spoilage rating recorded was only 17.9% on day 14. On average, APC were the highest, starting at 6.5 Log CFU/g on day 0. From day 4 to 8, APC counts rose (P < .05) to 7.6 Log CFU/g. While EB and ECC steadily increased (P < .05) over the 14-d display period, both methods showed only a 1-Log increase during days 4 to 8. Additionally, the microbiome shifted (P > .05) during this period from being predominantly composed of Lactobacillus species to Pseudomonas species. Logistic regression models were developed to predict purchase intent and spoilage classification. Common threshold values of 50%, 75%, 90%, and 95% were identified for purchase intent and 5%, 10%, 25%, and 50% for spoilage classification in regard to microbial enumeration. Models generated for all microbial measurements corresponding to consumer visual appearance were the strongest (P < .05). APC accounted for 59% of the variation within the model, with values of 7.3, 6.7, 6.1, and 5.8 Log CFU/g corresponding to a 50%, 75%, 90%, and 95% chance of consumer purchase. According to the appearance, consumers were 5%, 10%, 25%, and 50% likely to rate samples as spoiled when APC were 5.3, 5.9, 6.8, and 7.7 Log CFU/g (R² = 0.46; P < .05). When APC reached 7 Log CFU/g, consumers were 60% likely to purchase the sample and only 30% likely to rate the sample as spoiled.

Conclusion: Throughout the 14-d display period, color change was the primary factor influencing consumers’ determination of ground beef spoilage. Although microbial growth steadily increased, and a shift in the microbiome occurred, our results indicate no objective measurements conclude that microbial activity was the main driver of color change. While spoilage ratings based upon touch and odor increased over time, consumers did not perceive a difference in taste, even with the extended age of the product. Therefore, in this study spoilage in ground beef is primarily determined by the consumer’s perception of appearance, with microbial growth having no direct impact on this assessment.

Figure 1.

Percentage of samples classified by consumers as “spoiled” based upon appearance, touch, odor, and taste ratings across all days of display compared to aerobic plate counts. APC, aerobic plate counts.

Funding Source: Kansas State University.

Keywords: spoilage, ground beef, microbial, consumer.

7 Is It Time for Super Prime?

Chesney A. Effling^*, Lauren M. Frink, Mason J. Prester, Stephanie L. Witberler, Greta E. Huber, Samuel F. Stickley, Sidney A. Munk, Erin S. Beyer, Morgan D. Zumbaugh, Jessie L. Vipham, Michael D. Chao, and Travis G. O’Quinn, Kansas State University, Manhattan, KS 66506, USA *ceffling@ksu.edu

Introduction/Objectives: Over the past 25 y, the US beef industry has experienced a steady improvement in carcass quality, most notably in the increased percentage of carcasses grading prime. According to the National Beef Quality Audit, only 2.0% of carcasses graded prime in 2000 compared to 7.8% in 2021. Despite this shift, most value-based marketing programs continue to emphasize top choice carcasses, with prime often treated as a single, undifferentiated category. As prime availability grows, there is an opportunity to better characterize and capture added value from variation within the prime grade. However, little research has been done to evaluate consumers’ perception of upper 2/3 prime steaks when compared to other quality grades. Therefore, the objective of this study was to evaluate consumer palatability preferences in striploin steaks of upper 2/3 prime when compared to low prime, upper 2/3 choice, and low choice.

Materials and Methods: An equal number (n = 15) of beef striploins representing 4 marbling categories were collected from a commercial packing facility. The marbling categories represented were as follows: super prime (moderately abundant and abundant), low prime (slightly abundant), top choice (modest and moderate), and low choice (small). Subprimals were fabricated into 2.5-cm-thick steaks and vacuum packaged. Additionally, steaks were designated to 1 of 3 degrees of doneness (DOD): rare (R, 60°C), medium (MED, 71°C), and well done (WD, 76°C). Upon reaching the designated aging period of 28 d, steaks were frozen at −20°C until subsequent analyses. Consumers (N = 192) evaluated samples for juiciness, tenderness, flavor, and overall liking on a 100-point continuous-line scale. Anchors were designated on both ends as well as at the midway point with descriptive terms for each, with 0 being extremely dry, tough, and dislike extremely and 100 being extremely juicy, tender, and like extremely. Consumers were then asked an additional question to determine if the sample was acceptable or unacceptable for each of the sensory traits evaluated. Responses were recorded using a digital survey on an electronic tablet. Steaks designated for consumer panels were thawed at 2°C to 4°C for 24 h prior to testing. Steaks were then cooked on an electric flat-top grill utilizing a weighed steak press to their respective assigned DOD. Temperatures were monitored using a Type K Thermocouple. R steaks were flipped at 27°C and pulled at 53°C for a peak temperature of 60°C. For a MED DOD, steaks were flipped at 30°C and pulled from the grill at 68°C for a peak temperature of 71°C. WD steaks were flipped at 32°C and pulled at 74°C for a peak temperature of 76°C. Consumers were served two 1.3 × 1.3 × 2.54 cm³ cubes per sample. All final peak temperatures were collected. Data were analyzed using a split-plot design in SAS, with quality grade as the whole-plot factor and DOD as the subplot factor. Statistical significance was set at 0.05.

Results: There were no (P > .05) interactions between quality grade and DOD for any consumer-evaluated traits. When evaluating the main effect of quality grade, super prime steaks were juicier, more tender, and rated higher for flavor and overall liking (P < .05) than all other grades. No differences (P > .05) were observed among low prime, top choice, and low choice for juiciness, flavor, and overall liking. Tenderness ratings were similar (P > .05) between low prime and top choice and between top choice and low choice. However, low prime steaks rated higher (P < .05) compared to low-choice steaks for tenderness. Additionally, a higher percentage of super prime steaks rated as acceptable (P < .05) for juiciness, tenderness, flavor, and overall liking than all lower grades. No differences (P > .05) were found in the percentage of samples rated acceptable for tenderness between low prime and top choice steaks and top choice and low-choice steaks. However, a higher percentage (P < .05) of consumers rated low prime steaks as acceptable for tenderness than low-choice steaks. When evaluating the main effect of DOD, R steaks were juicier, more tender, and rated higher overall (P < .05) than MED and WD steaks. However, MED and WD steaks rated similar (P > .05) for juiciness, tenderness, and overall liking. No differences (P > .05) were found between R and MED steaks, and MED and WD steaks for flavor liking. However, R steaks were rated higher (P < .05) than WD steaks for flavor liking. Additionally, a higher percentage (P < .05) of R steaks rated as acceptable for juiciness than MED steaks and a higher percentage (P < .05) of MED steaks rated as acceptable for juiciness than WD steaks. A higher percentage (P < .05) of R steaks rated as acceptable for tenderness than MED and WD steaks. However, there was no difference (P > .05) in the percentage of MED and WD steaks that rated acceptable for tenderness. For overall acceptability, no differences (P > .05) were found in the percentage of samples rated acceptable between R and WD steaks or WD and MED steaks. However, a higher percentage (P < .05) of WD steaks rated as acceptable than MED steaks for overall acceptability. DOD had no impact (P > .05) on the percentage of samples rated acceptable for flavor liking.

Conclusion: Regardless of DOD, super prime steaks outperformed all other quality grades in all sensory traits evaluated by consumers. These results indicate that consumers preferred the eating quality of upper 2/3 prime steaks over the other grades evaluated. This supports the opportunity for a premium program within the prime grade, offering the beef industry a valuable opportunity to capture added value from this highest grade within beef.

Funding Source: Kansas State University.

Keywords: beef, consumer, palatability, prime, quality.

8 Consumer Evaluation of Breaded Fried Chicken Fillets

Blake Robbins^*, Grace Harris, Keayla Harr, Jameson Anna Scott, Ranjith Ramanathan, Gretchen Mafi, and Morgan Pfeiffer, Oklahoma State University, Stillwater, OK 74078, USA *blake.robbins@okstate.edu

Introduction/Objectives: The rise in consumption of chicken sandwiches has led to increased emphasis on the production of breaded chicken fillets. Currently in industry, during production of breaded chicken fillets, breasts are split into top and bottom portions before further processing. Fillets halves are then marinated before going through a predust, batter, breader system, then par fried, frozen, packaged, and shipped. A previous industry study showed that top and bottom breaded chicken fillets were significantly different in instrumental texture values. Therefore, the objective of this study was to determine consumer perceptions of top and bottom breaded fried chicken fillets sensory attributes.

Materials and Methods: One-hundred and forty-eight fillets (n = 74 tops and 74 bottoms) were cooked in groups of 12, split evenly between tops and bottoms. Samples were deep fried in vegetable oil in a commercial fryer at 177°C for 6 min and 25 s. After frying, internal temperatures were measured with a calibrated meat thermometer to ensure the internal temperature exceeded 74°C. Each fillet was assigned a random number then cut into 8 triangular pieces of similar sizes. Pieces were placed into sample cups and kept warm in an insulated warming bag. Panels were conducted at Francis Tuttle Culinary Institute in Oklahoma City, Oklahoma and Oklahoma State University in Stillwater, Oklahoma. One-hundred and fifty (n = 150) panelists participated. Panelists were compensated with a $10 gift card for their time. Each panelist was served 6 samples, 3 tops and 3 bottoms. Panelists completed a digital Qualtrics ballot including a consent form, demographic questions, and the following questions about each sample: overall like/dislike of the product, overall texture, overall tenderness, overall juiciness, overall crispiness, overall saltiness, how much they liked the tenderness of the product, and how much they liked the juiciness of the product. Responses were assigned a numerical value for each question. For overall liking questions, numbers 1 to 7 were used with lower values indicating less acceptance and higher values greater acceptance. For overall texture, tenderness, juiciness, crispiness, and saltiness questions, values of 1 and 2 indicated not tender, juicy, crispy or salty enough; 3 indicated “just about right”; and 4 and 5 indicated too tender, moist, crispy, or salty. Fillet type (top or bottom) and consumer perception were compared using the GLIMMIX procedure of SAS to determine differences in texture, tenderness, crispiness, juiciness, and overall liking with differences determined at a P value of less than .05.

Results: Consumer found tops to be more acceptable (P < .05) for overall liking than bottoms with respective mean ratings of 5.05 for tops and 4.77 for bottoms. When asked about overall texture of the product, consumers rated bottoms with an average score of 2.76 and tops 2.79, showing no difference (P > .05) between tops and bottoms. Consumers found no difference (P > .05) in overall tenderness, juiciness, or crispiness between top and bottom halves of fillets. Consumers detected a difference (P < .05) in overall saltiness of the product, finding bottom halves being less salty than tops, with an average score of 2.92 and 3.07, respectively. When asked about their liking of the tenderness or juiciness of the product, consumers found no difference (P > .05).

Conclusion: The results suggest consumers had a greater overall liking of tops than bottoms, which was to be expected as tops are normally considered higher quality cut than bottoms. Interestingly, consumers indicated no differences in texture or tenderness for tops and bottoms. Improved liking of tops can also be attributed to saltier tops than bottoms. The current study suggests that fillet location and ingredients can influence overall liking. Further research into tops and bottoms utilizing different breading systems would be beneficial to observe these effects across a variety of products.

Keywords: poultry texture, consumer preference.

9 Challenges of Dry-Aging Programs in the Southern United States

Peyton Arnold^1,*, Nick E. Johnston², and Derico Setyabrata¹, ¹Department of Animal Science, University of Arkansas, Fayetteville, AR 72701, USA, ²School of Human Environmental Sciences, Hospitality Management, University of Arkansas, Fayetteville, AR 72701, USA *peytona@uark.edu

Introduction/Objectives: The popularity and demand for dry-aged meat have increased significantly among consumers in recent years. Dry aging is a traditional meat processing technique that enhances the palatability of meat, particularly by improving tenderness and developing distinctive flavors, such as buttery and nutty notes. These attributes have been widely recognized as key drivers of consumer interest. Despite this growing demand, many meat processors have been slow to adopt dry-aging programs, potentially missing opportunities for economic growth and product diversification. Therefore, this study aimed to identify the key challenges and barriers faced by meat processors in implementing dry-aging programs. By understanding the practical, regulatory, and economic concerns of regional producers, we hope to provide insight into the support needed to expand dry-aged offerings and better meet consumer expectations in the region.

Materials and Methods: A semistructured survey was conducted via the Qualtrics survey platform. Participants (n = 100) recruited for the study were those who currently have an active role in the sale, purchase, or development of meat products in their respective businesses. The survey included both quantitative and qualitative components, assessing respondents’ knowledge, participation, and perceptions regarding dry-aging practices and products. Descriptive statistics were used to analyze demographic data and key themes from open-ended responses. Survey questions explored operational scale, current use of dry-aging techniques, familiarity with dry aging, perceived benefits and challenges, and interest in program adoption.

Results: The results showed that 79% of respondents were owners, general managers, food purchasers of butcher shops, distributors, and other food-related businesses. The remaining 21% were active in the food service industry (steakhouses and casual dining), mainly as chefs. A majority (51%) of the respondents represented small operations (10–49 employees). Currently, 68% of respondents produce dry-aged meat, while 24% offer both wet- and dry-aged products. Notably, 28% of those producing dry-aged meat have been doing so for less than 3 y. Knowledge levels varied, with 37% identifying as having basic knowledge and 28% as having intermediate knowledge of dry-aging techniques. Beef was the most common dry-aged protein, followed by pork, lamb, poultry, and wild game. Among respondents who were not currently practicing dry aging, 75% of participants were interested in adopting such program into their business. Key challenges reported by current dry-aged producers included the cost of equipment (83%), consumer demand (75%), and product sourcing (60%). Safety and regulatory concerns were cited less frequently (20% and 36%, respectively). Maintaining precise environmental conditions, temperature, airflow, and humidity, was emphasized as critical to product quality and safety. Profitability remains a major concern. A significant portion of producers are not fully utilizing byproducts from the dry-aging process. Overall, only 41% reported using crust and trim waste, most commonly incorporating it into further processed products (29%) or using it for sauces and stocks (29%).

Conclusion: This study highlights the primary concerns and opportunities for expanding dry-aging programs among meat processors in the southern United States. While consumer interest continues to rise, producers face economic and operational barriers, with equipment costs and inconsistent demand being the most pressing. Improved education and training on the best dry-aging practices, particularly in managing environmental controls and utilizing byproducts, could enhance profitability and efficiency. Expanding awareness of dry-aged meat’s value and potential applications may also drive consumer demand. The development of targeted outreach and technical support resources will be essential in helping producers successfully implement dry-aging programs. Future surveys will aim to capture a broader understanding of current practices and the long-term impact of dry-aging programs on regional meat markets.

Funding Source: This project is funded by the Arkansas Beef Council.

Keywords: dry aging, barriers, producers, survey, waste.

10 High-Pressure Processing Reverses Dark-Cutting Beef to Normal Bright-Red Color: A Study on Consumer Perception

Madison Muller^1,*, Morgan Pfeiffer¹, Rodney Holcomb¹, Mary-Grace Danao², Gary A. Sullivan³, Jordan C. Wicks³, Gretchen Mafi¹, Ranjith Ramanathan¹, ¹Department of Animal and Food Sciences, Oklahoma State University, Stillwater, OK 74078, USA, ²Department of Food Science and Technology, University of Nebraska–Lincoln, NE 68588, USA, ³Department of Animal Science, University of Nebraska–Lincoln, Lincoln, NE 68583, USA *madison.muller@okstate.edu

Introduction/Objectives: Approximately $210 million is lost annually due to dark-cutting conditions of beef. The 2021 National Beef Quality Audit reported that the occurrence of dark-cutting beef is a missed opportunity for the beef industry. Dark cutters are often discounted during grading and are not sold in retail due to their appearance and reduced shelf life. This leads to an approximate $200 discount per carcass. Recently, we demonstrated that applying high pressure to dark-cutting beef can reverse the dark color. However, there is limited knowledge of consumer perception of improved redness in dark-cutting beef. The objective of the study was to understand consumer perception of improved redness in dark-cutting beef following high-pressure application.

Materials and Methods: Two separate studies were conducted to understand consumer perception using Tobii Pro 3 glasses and a digital survey using images of steaks. No-roll dark-cutting loins (mean pH = 6.4) and normal-pH loins were purchased from a beef processing facility within 3 d to 5 d of harvest. Loins were cut into equal sections, vacuum packaged, and randomly assigned to high-pressure processing (HPP) treatment of 0 (no HPP), 300, or 450 megapascals (MPa) with a holding time of 90 s. Normal-pH beef was not HPP treated and served as a control. Loins were transported to Oklahoma State University and aged for approximately 14 d. Following aging, steaks were bloomed for 1 h at 4°C and used for taking digital images and consumer perception analysis using Tobii Pro 3 glasses. Tobii Pro 3 is a wearable eye-tracking system designed to study human behavior and attention in various real-world settings. For the Tobii Pro 3 study, the 8 samples were placed in a retail case. Participants were asked to wear the Tobii Pro 3 glasses for 30 s and to examine the samples like they would in a grocery store. To simulate an in-store setting where consumers make purchasing decisions, participants (n = 56) were asked to wear Tobii Pro 3 glasses for 30 s, visually evaluate the steaks in the retail case, and then were given a survey. For the consumer survey, untrained consumer panelists (n = 163) were recruited and filled out a digital survey (Qualtrics Software). The survey consisted of 4 digital images of steaks (normal-pH control, dark-cutter without HPP, 300 MPa dark-cutting beef, and 450 MPa dark-cutting beef), demographic information, beef purchasing questions, and sample evaluation questions. The survey was created using Qualtrics and distributed via email and social media links. The data were expressed as a percentage in each category.

Results: The Tobii Pro 3 glasses study found that participants gazed longer at normal-pH bright-red steaks (20.03 s) than at other steaks, while their gaze time was shorter for 450 MPa steaks (8.72 s), likely due to the paleness associated with pressure application. Since all steaks were presented simultaneously, participants did not gaze longer at the 300 MPa steaks (9.6 s), even though their redness was enhanced. The participants in the digital survey came from 8 different states in the central United States. Eighty-one percent of the participants indicated that normal-pH beef was their first purchasing choice. Only 3% of participants stated they would prefer the dark-cutting steak without HPP. Steaks subjected to 300 MPa for 90 s enhanced consumer preference, with 57% of participants preferring it as their second choice after normal-pH steaks.

Conclusion: The research suggests that 300 MPa HPP improved the redness of dark-cutting steaks. Improved redness is also associated with improved consumer purchasing decisions. Future consumer studies utilizing multiple triangle tests will enhance our understanding of specific consumer preferences for normal-pH bright-red steaks, high-pressure dark-cutting steaks, and dark-cutting steaks without HPP. Therefore, conducting a cost/benefit analysis of improved redness (i.e., recovered retail value) associated with HPP and determining the potential return on investment for incorporating HPP into a commercial-scale packing facility will help add value to the beef industry.

Funding Source: Research coordinated by the National Cattlemen’s Beef Association, a contractor to the Beef Checkoff.

Keywords: dark-cutter, HPP, consumer, Tobii Pro.

11 Investigating the Prevalence of Red Meat Allergy in Kansas Rural Communities

Jordan T. Looper¹, Sara R. Hene¹, Sabrina D. Lee¹, Alexandra P. Tegler¹, Yoonseong Park², Priscilla Brenes³, and Michael D. Chao^1,*, ¹Department of Animal Sciences and Industry, Kansas State University, Manhattan, KS 66506, USA, ²Department of Entomology, Kansas State University, Manhattan, KS 66506, USA, ³Department of Food, Nutrition, Dietetics and Health, Kansas State University, Manhattan, KS 66506, USA *mdchao@ksu.edu

Introduction/Objectives: Alpha-gal syndrome (AGS), also known as red meat allergy, is an acquired allergic reaction to galactose-alpha-1,3-galactose (α-Gal), a carbohydrate conjugated to glycoproteins and glycolipids of nonprimate mammals. Sensitization to α-Gal occurs following a bite from the Lone Star tick (Amblyomma americanum). As a result, affected individuals experience a range of allergic symptoms, from gastrointestinal distress to potentially fatal anaphylaxis, following the consumption of mammalian products. Although the number of AGS cases in the United States has increased over the years, limited research has been conducted to determine its prevalence and public awareness at the state level. The importance of this work is exacerbated as Lone Star tick populations and species range increases. Today, states like Kansas are experiencing historically unprecedented incidence rates of AGS. Thus, the objective of this study was to gain a better understanding of AGS awareness, prevalence, and disease management through community surveys across the state of Kansas.

Materials and Methods: Three listening sessions were conducted across the state (Parson, Kansas; Salina, Kansas; and online via Zoom) to engage with local Kansas State University extension agents and build relationships for survey distribution in their service area. Incentivized paper and electronic (Qualtrics) surveys were distributed through Kansas County extension agents to local communities across Kansas (IRB-12256). Electronic survey responses were validated using CAPTCHA scores, geolocation data, and provided home addresses to ensure submissions were from individuals in the state of Kansas. The survey comprised 23 questions aimed at assessing respondents’ awareness and knowledge of AGS, their familiarity with other affected individuals, key demographic and lifestyle factors, and their interest in obtaining further information on the condition.

Results: Of the 579 surveys returned, only 165 surveys were validated from this study (28.5%). The northeastern (35.2%) and south central (32.1%) regions of Kansas had the highest response rate, closely followed by the southeast (25.5%). The southwest (1.21%) and northwestern (1.21%) regions of Kansas had the lowest response rate. Ninety-five point eight percent of respondents had heard of AGS, and 86.1% responded they were familiar with the symptoms of the allergy. More than 50% of the respondents knew AGS was associated with abdominal pain, diarrhea, hives, itching, nausea, and swelling of the lips, eyes, or face, but few respondents knew AGS patients may experience respiratory symptoms like cough, wheezing, and shortness of breath. In terms of prevalence, 80.6% of respondents said they or someone they knew have/had AGS (80.6%). Of the 553 reported AGS cases, Crawford County, followed by Montgomery County, both located in the southeastern region of the state, had the highest number of reported cases with 78 and 51, respectively, while only 1.4% were from the western regions of Kansas. Despite the large number of reported cases, only 1.8% of respondents believed there was sufficient information about AGS available, and 75.2% were interested in receiving more structured information regarding the topic.

Conclusion: The survey results reveal that many Kansans citizens either suffer from AGS themselves or know someone in their community who does. Most of the AGS cases were concentrated to the eastern half of the state, particularly in the southeastern corner. However, as climate change continues to drive the Lone Star tick’s northern and westward expansion, the number of AGS cases may continue to rise in northern and western Kansas. To further expand on this research, our group is conducting interviews with patients who have had AGS diagnosed in Kansas to better understand the challenges they face and to establish a targeted approach that may help alleviate biological, social, and economic effects of AGS.

Funding Source: Kansas State University Global Food Systems Seed Grant Program.

Keywords: Alpha-gal syndrome, survey prevalence.

12 Ice Age: Investigating the Impact of Freezing and Aging Order on the Palatability of Historically Tough Muscles

Taylor M. Dieball^1,*, Greta E. Huber¹, Samuel F. Stickley¹, Kiersten M. Gundersen², Kasey R. Maddock Carlin², Morgan D. Zumbaugh¹, Michael D. Chao¹, Jessie L. Vipham¹, Travis G. O’Quinn¹, and Erin S. Beyer¹, ¹Kansas State University, Manhattan, KS 66506, USA, ²North Dakota State University, Fargo, ND 58105, USA *dieballt@ksu.edu

Introduction/Objectives: Beef is often aged and frozen to improve and then maintain quality. While aging improves tenderness through proteolytic degradation, freezing also improves tenderness through the formation of ice crystals. High end food services utilize aging, while keeping the product fresh to preserve tenderness. However, most of the beef in commercial supply chains is aged before freezing. In contrast, there have been studies that have shown that freezing and then aging can be a viable option as well. However, there has been little research done to determine how freezing sequence impacts consumer ratings, instrumental tenderness, or objective color readings of muscles. This study aimed to assess how freezing and aging sequences influence consumer eating experience, tenderness, and objective color readings of 3 different beef muscles.

Materials and Methods: Beef carcasses (N = 12; US Department of Agriculture choice; A maturity) were selected from a Midwest beef plant. The trimmed striploins (IMPS #180) and goosenecks (IMPS #170) were collected and transported to North Dakota State University. The striploins (LL), semitendinosus (ST), and biceps femoris (BF) were denuded and sliced into 2.5-cm steaks. Each steak was assigned to either age-then-freeze (AF) or freeze-then-age (FA) for 21 d or 28 d. All steaks were aged before or after freezing between 1°C and 4°C in the absence of light. Steaks were frozen before or after aging for 91 d at −20°C. Samples were then thawed for 24 h at refrigerated temperatures. Consumers (N = 96/aging period, N = 192 total) were fed all treatment combinations within a single aging period. Samples were cooked to a peak temperature of 71°C using a Thermapen temperature probe on a clamshell griddle. Consumers evaluated each sample based on flavor liking, juiciness, tenderness, and overall liking. Each trait was rated on a 100-point line scale, with anchors set at 0, 50, and 100, with 0 being dry, tough, and undesirable and 100 being juicy, tender, and desirable. Consumers determined the overall quality of each sample selecting from unsatisfactory, everyday quality, better than everyday quality, or premium quality. Consumer panel data were collected on electronic tablets using Qualtrics. On the following day, 1 steak from each muscle and treatment combination was evaluated for Warner-Bratzler shear force (WBSF), cook loss, purge loss, and color. Steaks were weighed in the package, opened, and weighed again to calculate purge loss. Each sample bloomed for 20 min, and a raw color reading was taken using a spectrophotometer. Steaks were cooked to a peak temperature of 71°C. After 24 h, 6 cores were taken parallel to the muscle fiber. Cores were sheared perpendicular to the fibers on the WBSF machine, and readings were recorded as average kilograms of force. Data were analyzed using SAS PROC GLIMMIX as a split–split-plot design with the whole-plot factor set as primal, subplot factor set as freezing treatment, and sub-sub plot factor set as aging period. α was set at 0.05.

Results: As a whole, the freezing treatment and aging period did not impact the tenderness, flavor, or overall liking scores for the consumer. However, there was an aging period × freezing treatment × muscle interaction (P < .05) for juiciness. The consumers rated the 28-d FA LL as the juiciest (P < .05) compared to all other treatment combinations. As expected, the tenderness scores were significant for muscle, as the LL was rated as the most tender (P < .05), followed by the ST and BF. Within flavor liking, the consumers rated the LL the highest (P < .05) for flavor liking. Similarly, consumers rated the LL the highest (P < .05) for overall liking. Additionally, the highest (P < .05) percentage of consumers rated the LL as better than everyday quality compared to the other muscles. The greatest (P < .05) percentage of consumers determined the BF was in the unacceptable quality. Supporting the consumer data, the shear force assay found the LL had the lowest shear force (P < .05) value, being the most tender, followed by the ST, and then the BF. Contradicting the consumer’s rating for juiciness, the FA samples had the greatest (P < .05) amount of purge loss (12.79%), and the LL had the lowest (P < .05) amount of purge loss (6.29%). However, the AF samples had the greatest (P < .05) amount of cook loss. Raw color was taken to indicate any impact on raw meat quality. The raw color readings indicated that there was an interaction (P < .05) for L* values, with the 21-d AF ST having the highest (P < .05) L* value. There was also an interaction in a* between the freezing treatment and muscle (P < .05), with the AF ST, having the highest a* value as the brightest, most cherry red in appearance. There was another interaction (P < .05) for oxymyoglobin, deoxymyoglobin, and metmyoglobin percentages, with the 21-d ST having the highest oxymyoglobin percentage and lowest deoxymyoglobin and metmyoglobin percentages.

Conclusion: This study found that reversing the freezing order did not impact the overall palatability of beef steaks from the loin and round. On the contrary, it led to a higher purge loss, increasing the potential for economic loss. While previous studies showed promising results reversing the freezing order, when historically tough muscles from the round were included, the positive impact on tenderness was obsolete. Therefore, reversing the sequence of freezing and aging is not a viable strategy for the industry.

Funding Source: Research coordinated by the National Cattlemen’s Beef Association, a contractor to the Beef Checkoff.

Keywords: beef, freezing, palatability, aging, consumer.

13 Impact of Consumer Storage Practices and Packaging Type on Refrigeration Shelf Life and Quality of Ground Beef Purchased From Commercial Retailers

Ashlynn Messer^*, Elizabeth Neal, Benjamin Carpenter, Jerrad Legako, ¹Department of Animal and Food Sciences, Texas Tech University, Lubbock, TX 79415, USA *asmesser@ttu.edu

Introduction/Objectives: The objective of this study was to evaluate the impact of consumer storage practices and packaging type on the refrigeration shelf life and quality of ground beef purchased from multiple retailers.

Materials and Methods: Eighty-one packages of 80 to 20 ground beef were purchased from 5 national and regional retailers based on packaging type availability. Packaging types included: vacuum (VAC, n = 27), polyvinyl chloride overwrap (PVC, n = 27), and modified atmosphere packaging (MAP, n = 27). To simulate consumer behavior, ground beef packages were purchased, immediately transported to Texas Tech University, and placed in a common upright refrigerator (2–4°C). Packages were assigned to 1 of 3 refrigerated storage durations including 0, 3, and 7 d, during which temperature was continuously maintained at 2°C to 4°C. At each designated duration, samples were removed from refrigeration and evaluated for descriptive visual color, instrumental color, odor attributes, and spoilage organism content. Following evaluation, samples were flash frozen and homogenized for subsequent thiobarbituric acid reactive substances (TBARS) analysis. Descriptive color was evaluated by 6 trained panelists using an 8-point scale, where 1 = very bright red and 8 = tan to brown. Discoloration was characterized as percentage in a range from 0 to 100. Instrumental color was evaluated using a HunterLab spectrophotometer to collect L*, a*, and b* values. Panelists also evaluated 4 odor attributes including overall intensity, oxidized, putrid, and sour on a scale of 0 to 100. Additionally, a 10 g portion of each sample was collected and evaluated for aerobic count (AC), Enterobacteriaceae (EB), and lactic acid bacteria (LAB) growth. Data were analyzed as a randomized block design, where packaging type, storage time, and their interaction served as fixed effects. Significance was determined at less than or equal to 0.05.

Results: An interaction of packaging type × storage duration was observed for a* values (P < .001). At 0 d of refrigeration, MAP packages exhibited the greatest a* values, followed by PVC, then VAC (P < .05). However, after 7 d of storage, while MAP maintained the most redness, VAC resulted in higher a* values than PVC packages, indicating some extent of discoloration (P < .05). There was no packaging type × storage time interactions observed for any measurement of descriptive color, odor, spoilage organisms, or TBARS (P > .05). Descriptive color assessments were impacted nonetheless by packaging type (P < .001). More specifically, MAP packages resulted in the lowest color score, indicating a brighter, more cherry-red appearance (P < .001). In terms of discoloration, the greatest percentage of discoloration was observed within the PVC packages in comparison to both VAC and MAP (P < .001). Additionally, packaging type influenced instrumental L* values, where PVC packages were considered to be the brightest, followed by VAC and MAP (P < .001). Similarly, odor was also impacted by packaging type. In greater detail, MAP packages had a greater overall intensity and were more putrid, oxidized, and sour in comparison to PVC or VAC (P < .05). Likewise, spoilage organisms were also influenced by packaging type (P < .05), where EB was the greatest among PVC packages and LAB the greatest among MAP packages. Finally, packaging type impacted TBARS values (P < .001), where the greatest concentration of malondialdehyde was observed in PVC packages, especially compared to MAP packages. Furthermore, certain analyses were also impacted by the storage time (P < .05). More specifically, descriptive color analysis values were impacted by day, where the greatest color score and percent discoloration was observed after 7 d (P < .001). This change in color throughout storage was reflected in instrumental color values, where L* was lowest at 0 d and greatest at 3 d (P < .001). Similarly, descriptive odor panels were also impacted by refrigeration time (P < .001), where packages stored for 7 d resulted in the highest score for overall intensity, oxidized, putrid, and sour. The growth of spoilage organisms was also impacted by storage time (P < 0.05), where AC, EB, and LAB were all highest after 3 d of refrigeration. Storage time had no impact on TBARS values (P > .05).

Conclusion: In conclusion, these results indicate that packaging type and storage duration independently impact the shelf life and quality of refrigerated ground beef. Thus, when making purchasing decisions at retail, consumers should give special consideration to the packaging type as well as the intended storage duration to improve the subsequent eating experience. It can be seen that ground beef purchased in MAP and stored at a consistent temperature maintains the brightest red color but has high amounts of bacterial growth and is highest in odor intensity after 7 d.

Funding Source: This study was funded by the Davis College Undergraduate Research Scholars Program at Texas Tech University.

Keywords: ground beef, quality, shelf life, refrigeration.

14 What’s the Beef With Consumer Appeal?

Kelli G. Garrett^*, Stephanie L. Witberler, Greta E. Huber, Erin S. Beyer, Jessie L. Vipham, Morgan D. Zumbaugh, and Travis G. O’Quinn, Kansas State University, Manhattan, KS 66506, USA *kelli39@ksu.edu

Introduction/Objectives: Meat color is the major factor affecting consumer purchasing decisions for beef in the retail case. Consumers typically associate a bright cherry-red color with fresh high-quality products, influencing the decision to purchase. Retailers and meat processors strive to maintain this optimal color to maximize sales and meet consumer expectations. Although this preferred beef color is recognized, minimal research has been conducted that precisely defines the specific hexadecimal code (hex) consumers prefer. Establishing a standardized color reference could provide valuable insights for the meat industry, bridging the gap between consumer perception and color identity. Therefore, the objective of this study was to determine the specific color consumers most prefer as the appealing bright cherry-red beef color.

Materials and Methods: Color samples (n = 25) were developed to represent variations of beef originating from a hex that was presumed to be the ideal bright cherry-red beef color. To explore the influence of color attributes on consumer perceptions, the original hex was systematically modified by adjusting the brightness and contrast levels, resulting in a 5 × 5 grid of color. The color sample development encompassed horizontal (A, B, C, D, and E) and vertical (1, 2, 3, 4, and 5) adjustments. From the central hex, 2 successive samples were generated to the left, each incrementally darker, simulating darker red tones. Conversely, 2 samples to the right were progressively lighter, depicting paler red hues. Similarly, moving upward from the central hex, 2 samples were incrementally brightened to enhance vibrancy, while 2 samples downward from the central hex were dulled to represent muted red tones. With 9 colors creating a base, 4 additional hexes were developed based on the interaction of 2 traits. For dark, bright-red, samples A1, A2, B1, and B2 were designed. Light, bright reds were formed in samples A4, A5, B4, and B5. Dark, dull reds were created as D1, D2, E1, and E2. Lastly, light, dull reds were represented from samples D4, D5, E4, and E5. A comprehensive survey using a square sample of each color behind a black background was formed using the Qualtrics platform. Consumers (N = 192) were presented with a random selection of 10 color samples out of the 25 developed. For each sample, consumers were asked to evaluate the color as if they were purchasing beef at retail by determining their overall liking and purchasing intent. The overall liking was determined using a 100-point line scale, where 0 indicated extremely dislike and 100 signified extremely like. Also, consumers were asked if they would purchase a beef steak (yes/no) with the selected color to determine purchasing intent. To ensure consistency, the survey was conducted on electronic tablets with a constant screen brightness. Data were analyzed using SAS PROC GLIMMIX as a completely randomized design with the SLICE function to restrict comparisons within rows and columns. α was set at 0.05.

Results: For the consumer liking results, samples were compared horizontally based on darkness to lightness and vertically based on brightness to dullness. For horizontal comparisons, each row (A, B, C, D, and E) contained samples numbered 1 to 5, with each compared to the other. For row A, A2 resulted in a higher (P < .05) overall liking score compared to A1 (darkest) and A5 (lightest), being similar (P > .05) to A3 and A4. In row B, B2, B3, B4, and B5 were all scored similar (P > .05) and higher (P < .05) than B1, which was the darkest. Similarly, for row C, C3 was rated higher (P < .05) than C1 (darkest) and C5 (lightest), while being similar (P > .05) to C2 and C4. As the hexes became duller than C, the consumers shifted their overall liking scores to favor the lighter hexes. In row D, the consumers rated D3 and D4 higher (P < .05) than D1 and D2, which were the 2 darkest hexes. Following the same trend for row E, E3, E4, and E5 were all rated higher (P < .05) than the darkest hexes of E1 and E2. Additionally, the color samples were analyzed vertically, comparing brightness to dullness within columns 1, 2, 3, 4, and 5. In column 1, the darkest column, consumers preferred A1, the brightest hex (P < .05), and decreased in liking descending to E1 (dullest). Similarly, column 2 displayed the same behavior of consumers favoring (P < .05) the brightest hex and decreasing liking down the column. For column 3, A3, B3, C3, and D3 were all rated higher (P < .05) than E3 (dullest). In the lighter colored column 4, consumers preferred brighter hexes over duller hexes. The brighter shades of A4, B4, and C4 were similar (P > .05) and all preferred (P < .05) over the duller hexes of D4 and E4. In column 5, B5 was rated higher (P < .05) than A5 (brightest), D5, and E5 (dullest), with C5 being similar (P > .05). The consumer purchasing intent results demonstrated similar findings as the consumer liking results.

Conclusion: For both consumer liking and purchasing intent scores, consumers favored the moderately light and bright hexes over the dark hexes regardless of brightness. However, as the hexes became duller, the consumers became even more critical of the darker hexes. The assumed descriptor of bright cherry-red beef preferred by consumers was identified as brighter colored (#C10100) beef that was moderate in darkness with extremes in lightness and especially darkness not being desirable to consumers.

Figure 1.

Least-square means of consumer (N = 192) liking scores for 25 variations of beef color hexadecimal codes.

Funding Source: Kansas State University.

Keywords: color, beef, retail, hex, consumer.

15 Determining the Ability of Consumers to Correctly Identify Ranges of Color and Marbling in Photos of Pork Loin Chops

Caroline J. Gill^*, Jenna M. Girman, Bailey N. Harsh, and Anna C. Dilger, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA *cjgill3@illinois.edu

Introduction/Objectives: While consumers make purchasing decisions for fresh pork loin chops based on many factors, visual appearances including color and marbling are thought to be important cues. However, the ability of consumers to differentiate between pork chops based on color traits or the amount of marbling is not clearly understood. The present study investigates consumer ability to correctly identify and order differences in objective and subjective color traits and in marbling of fresh pork loin chops.

Materials and Methods: Loin chops were evaluated for objective (L*, a*, b*) and subjective (National Pork Producers Council [NPPC]) visual color and scored for marbling (NPPC). They were then photographed using an iPhone camera (Apple, Cupertino, CA) on a consistent background. Chops were selected to represent a range of each trait while holding the other traits constant, resulting in 6 sets of loin chops. Photos were printed in color on glossy photo paper (DNP IAM, Mount Pleasant, PA) creating 6 card sets, 1 for each trait. For NPPC color, scores ranged from 2 to 5. For objective color, L* ranged from 42 to 56, a* from 4 to 11, and b* from 1.5 to 8. In each color set, there were 2 anchor cards representing the extremes for each trait and then 5 cards in between. Marbling was presented either in chops having lighter color (NPPC color scores 2.5–3) or darker color (NPPC color scores 4.5–5), with marbling scores ranging from 1 to 5. Each set contained 2 anchor cards representing the extremes for each trait and then 7 cards in between. Consumers (N = 137) were recruited from the greater Champaign-Urbana area. About 64% of consumers were female and the majority of consumers were Caucasian. A range of ages were present in the consumer sample. For each set of cards, consumers were asked to sort photos of chops between the 2 anchor points for each deck. Responses were recorded and scored out of 100 points, where each “pair switch” deducted 2.5 points from the consumer’s total score. Mean scores were calculated overall for each card set (trait) as well as by age groups and gender. Because the scores were not normal, nonparametric testing was utilized to determine significance without the assumption of normality. Differences in means were evaluated using the Kruskal–Wallace test in R Studio. Post-hoc testing using Dunn’s test was performed to determine within group differences. Significance was determined at a P value of less than .05.

Results: Consumers were more able to correctly order (P < .05) card sets (greater scores) that represented a range of lightness (L*) and NPPC visual color values compared with those that represented ranges in yellowness (b*) and redness (a*). Scores were the least (P < .05) among color set cards for a*. Between marbling sets, consumers scores were greater (P < .05) for marbling ranges in the light-colored set compared with the dark colored set. The ability to sort color or marbling card sets was not affected by consumer gender or age (P > .05).

Conclusion: The data suggest that consumers more easily detected changes in lightness (L*) and NPPC color compared with other color traits. Surprisingly, consumers were the least able to sort cards correctly based on redness differences. Also, consumers were better at correctly ordering marbling differences when chops were lighter in color.

Keywords: pork, color, consumer, marbling.

16 Yucca schidigera and Quillaja saponaria: A Natural Approach to Mitigating Greenhouse Gas Emissions

María Camila Duarte^1,*, Matt Garner², Clinton J. Roof¹, and Alexandra Calle¹, ¹School of Veterinary Medicine, Texas Tech University, Amarillo, TX 79106, USA, ²Vvntus Lab LLC, Amarillo, TX 79101, USA *mariadua@ttu.edu

Introduction/Objectives: Methane emissions from ruminant livestock represent an environmental concern, as they contribute to greenhouse gas emissions and climate change. Thus, enteric methane reduction should be a critical goal for sustainable livestock systems. Dietary interventions using plant-derived compounds have gained attention among various mitigation strategies due to their potential to modify rumen fermentation. Yucca schidigera (YS), a plant native to arid regions of North America, and Quillaja saponaria (QS), derived from the bark of a South American soapbark tree, both contain saponins, which may contribute to methane emissions reduction by altering microbial populations, inhibiting methanogens, or modifying fermentation pathways. However, their methane-reducing potential remains unclear, as their effects can vary depending on concentration, microbial community, and overall diet. This study aimed to assess in vitro the methane-reducing potential of YS and QS and provide insights into their role in sustainable feeding strategies for ruminants.

Materials and Methods: The effects of YS and QS on methane production were assessed separately using the Automatic Methane Potential Test System (AMPTS III), an automated system designed to measure real-time biogas production under anaerobic conditions, simulating rumen fermentation processes. Fresh rumen fluid was collected and used to inoculate anaerobic reactors. All reactors contained a base solution composed of rumen fluid, McDougall’s buffer, and glucose. Four concentrations of either YS or QS (0.05%, 0.1%, 0.5%, and 1%) were tested alongside positive (base solution with cellulose instead of glucose) and negative (rumen fluid and buffer only) controls. Samples in the AMPTS III were incubated at 37°C for 48 h. Gas production was continuously monitored, and methane was quantified. Each treatment was tested in triplicate. A 3-way analysis of variance (ANOVA) was performed to assess the effects of treatment, concentration, and time, with post-hoc Tukey’s tests for multiple comparisons. Statistical significance was set at a P value of less than .05. Although the AMPTS III system continuously monitors gas production, data were exported as cumulative daily methane values (24 h and 48 h). Time was treated as a fixed factor with 2 levels in the model.

Results: Overall, both products demonstrated a methane reduction with efficacy variations observed between the type of treatment and concentration. Significant differences were observed between YS and QS at all concentrations, with YS consistently achieving greater methane reduction (P < .05). At both 24 h and 48 h, all YS concentrations resulted in significantly lower methane levels compared to the positive control (P < .05). YS at 0.05% was the most effective, reducing methane by 49.9%. Although the 1% YS concentration also significantly reduced methane compared to the positive control (P < .05), 0.05% was significantly more effective at both timepoints. In contrast, for QS, only the 0.1% concentration showed a significant reduction at 24 h (P < .05), reducing methane by 17.6%. At 48 h, all concentrations, except 1%, significantly reduced methane compared to the positive control (P < .05). The 1% QS concentration neither outperformed 0.1% QS nor significantly reduced methane at 48 h (P > .05). The 3-way ANOVA showed a concentration-dependent response, indicating that the effects of YS and QS on methane reduction varied significantly with treatment, concentration, and time.

Conclusion: This study highlights the potential of YS and QS extracts as methane mitigation strategies in ruminant systems. The effectiveness of these plant-derived additives varied by concentration, with YS demonstrating consistently higher efficacy. These findings suggest that targeted supplementation with specific concentrations could optimize methane reduction. Integrating these extracts into cattle systems may reduce livestock’s environmental footprint while supporting sustainability and profitability. In vivo experiments are needed to demonstrate effectiveness in live systems.

Funding Source: This work was partially supported by Vvntus Lab LLC.

Keywords: methane, Yucca schidigera, Quillaja saponaria, sustainable systems.

17 Finishing Location Influences Carcass Characteristics, Meat Quality, and Terroir of Grass-Finished Bison Bulls

Garrett T. Weldy^1,*, M. Sebastain Hernandez², Christina E. Bakker¹, Judson K. Grubbs¹, Keith R. Underwood¹, Carter Kruse³, Jerrad F. Legako², and Amanda D. Blair¹, ¹Department of Animal Science, South Dakota State University, Brookings, SD 57007, USA, ²Department of Animal and Food Sciences, Texas Tech University, Lubbock, TX 79415, USA, ³Turner Institute of Ecoagriculture, Bozeman, MT 59718, USA *19gweldy@gmail.com

Introduction/Objectives: Approximately 70,000 bison were harvested in the United States in 2024. Bison bulls account for roughly 52% of the slaughter mix, and an estimated 32% of all bison are grass finished. Most bison are raised and finished across the vast landscape of the Great Plains, which is an approximately 2.9 million km² grassland composed of diverse ecosystems that vary in climate, terrain, rainfall, forage species, and micronutrient deposits. Research on other species indicates that both environment and diet composition can impact carcass characteristics and the terroir of meat. Terroir refers to the unique flavors and characteristics imparted to meat from the environment. However, studies investigating how variation in the grazing environment impacts carcass characteristics and meat quality outcomes of bison are limited. Therefore, the objective of this study was to determine the influence of finishing location on carcass characteristics, meat quality, and terroir of grass-finished bison bulls.

Materials and Methods: Bison bulls from a common source herd were grass finished in 3 geographically distinct locations of the Great Plains (n = 45 bulls/location): 1) Kansas (KS), 2) Nebraska (NE), or 3) Montana (MT). At approximately 30 mo of age, bulls were separated from their respective breeding herds and allowed to graze on native rangeland common to their geography for the finishing period (∼7 mo). The final live weight was recorded prior to slaughter, and bulls were slaughtered at approximately 37 mo of age. Hot-carcass weight (HCW), objective color (L*, a*, b*) of the 12th rib backfat and exposed surface of the ribeye, marbling score, ribeye area (REA), and backfat thickness were recorded following carcass chilling. Striploins were collected from a subsample (n = 30 carcasses closest to the average HCW of each treatment). Ultimate pH was measured at the posterior end of each striploin using a handheld pH meter. Striploins were fabricated into steaks (2.5-cm thick), which were vacuum packaged and aged for 14 d for analysis of objective tenderness, cook loss, sensory characteristics, and proximate composition. Steaks allocated for evaluation of objective tenderness using Warner-Bratzler shear force (WBSF) were weighed before and after cooking to calculate cook loss. Steaks allocated for sensory evaluation were evaluated by a trained sensory panel for subjective tenderness and flavor attributes. Subjective tenderness attributes include juiciness, muscle fiber tenderness, and connective tissue content. Subjective flavor attributes include bison identity, brown/roasted, fat-like, bloody/serum, metallic, liver-like, cardboard, bitter, salty, sour, sweet, umami, musty/earthy, green/hay-like, barnyard, animal hair, sour aromatic, and overall sweet. Steaks allocated for analysis of proximate composition were snap frozen in liquid nitrogen, powdered, and evaluated for percentage crude fat, crude protein, moisture, and ash. Carcass measurements, ultimate pH, subjective flavor attributes, and proximate analysis were analyzed with finishing location as a fixed effect using the GLIMMIX procedure of SAS. Subjective tenderness attributes, WBSF, and cook loss were analyzed with finishing location as a fixed effect and peak temperature included as a covariate using the GLIMMIX procedure of SAS.

Results: Overall, there were limited differences in carcass characteristics and meat quality attributes between the bison raised in MT and NE. However, bison from KS produced carcasses with lighter (P < .05) HCW compared to MT and NE and had a lower (P < .05) dressing percentage in contrast to MT bison. Dressing percentage of KS and NE bison did not differ (P > .05). Additionally, KS bison produced carcasses with lower (P < .05) marbling scores than the other 2 locations; however, backfat thickness did not differ (P > .05) among finishing locations. Carcasses from NE had larger (P < .05) REA than MT and KS, which were similar (P > .05). Carcasses from KS had higher (P < .05) L* (lighter) and lower (P < .05) a* (less red) values of the ribeye compared to NE or MT bison. Furthermore, KS carcasses had lower (P < .05) a* (less red) and lower (P < .05) b* (less yellow) values of the backfat compared to MT and NE bison. Finishing location did not influence (P > .05) the ultimate pH. Steaks from KS bison had increased (P < .05) WBSF, indicating a tougher product, while MT and NE steaks did not differ (P > .05) for WBSF. Cook loss did not differ (P > .05) among finishing locations. Trained sensory evaluation of juiciness, muscle fiber tenderness, and connective tissue did not differ (P > .05) among treatments. Panelists rated steaks from NE and MT higher (P < .05) for bison identity than steaks from KS. Panelists detected less (P < .05) liver-like flavor in steaks from KS and MT compared to NE. Steaks from MT had less (P < .05) sour aromatic flavor compared to NE, while KS was intermediate and did not differ (P > .05) from the other finishing locations. No differences (P > .05) were observed for any other subjective flavor attributes evaluated. Finishing location had no effect (P > .05) on the percentage of crude protein or moisture. However, steaks from MT had a greater (P < .05) percentage of crude fat than steaks from NE and KS, and steaks from KS had a greater (P < .05) percentage of ash than steaks from bison finished in the other 2 locations.

Conclusion: These data indicate that environmental differences among finishing locations can influence carcass characteristics and meat quality attributes of grass-finished bison bulls. Bulls finished in KS produced lighter carcasses, with less marbling, and were objectively less tender than bison finished in MT and NE. However, no differences were observed for subjective sensory scores for juiciness or tenderness, indicating the differences in objective tenderness may not have been extreme enough to be detectable by trained sensory panelists. The differences observed in select flavor attributes could be highlighted to promote subtle changes in terroir imparted by these regions. These findings indicate that the finishing environment contributes to differences in carcass composition, meat quality, and terroir, which can inform management and marketing strategies aimed at consumers seeking unique protein sources such as bison.

Funding Source: This research was supported by state and federal funds appropriated to South Dakota State University, including support from the South Dakota State University Agriculture Experiment Station, US Department of Agriculture’s National Institute of Food and Agriculture through the Hatch Act (accession #7008365), and by the Turner Institute of Ecoagriculture.

Keywords: bison, carcass, location, terroir, grass finished.

18 Targeting Heat Stress-Induced Inflammation With ω-3 Polyunsaturated Fatty Acid-Ca²⁺ Salts Partially Improved Growth Efficiency and Muscle Composition in Finishing Wethers

Shelley A. Curry^*, Melanie R. White, Ashley A. Hahn, Ty B. Schmidt, and Dustin T. Yates, University of Nebraska–Lincoln, Lincoln, NE 68588, USA *scurry4@huskers.unl.edu

Introduction/Objectives: Chronic heat stress induces systemic inflammation, which appears to play a key underlying role in poor muscle growth, feed efficiency, and body composition in finishing livestock. High adiposity near the end of the finishing period is an additional source of inflammation that may compound the effects of heat stress. Omega-3 polyunsaturated fatty acids (ω-3 PUFA) are bioactive nutrients with well-established anti-inflammatory properties. Thus, the objective of this study was to determine if targeting heat stress-induced inflammation with daily dietary supplementation of ω-3 PUFA would improve body composition and muscle characteristics in finishing wether lambs with high body fat.

Materials and Methods: Commercial Rambouillet-cross wether lambs (53.3 ± 0.4 kg) with high adiposity (≥5 mm ultrasonography-estimated backfat thickness) or normal adiposity (<5 mm ultrasonography-estimated backfat thickness) were fed ad libitum grower/finisher diets under heat stress (40°C, 35% relative humidity) or pair-fed under thermoneutral conditions (19°C, 15% relative humidity) for 21 d. Additionally, high-adiposity heat-stressed wethers were randomly assigned to receive 0 g/kg or 0.42 g/kg of an ω-3 PUFA Ca²⁺ salt supplement (STRATA, Virtus Nutrition). Thus, 5 groups of wethers were studied: 1) lean controls (n = 8), 2) high-adiposity controls (n = 8), 3) lean heat-stressed wethers (n = 8), 4) high-adiposity heat-stressed wethers (n = 8), and 5) ω-3 PUFA-supplemented high-adiposity heat-stressed wethers (n = 7). Wethers were weighed on days −1 and 21 of the study. Body composition was estimated in the live animals by bioelectrical impedance analysis (BIA) on days −1 and 21 of the study and in the carcass just after humane euthanasia on day 22. At necropsy, empty bodyweights were recorded following removal of the digestive tract. Biceps femoris, semitendinosus, flexor digitorum superficialis, soleus, gastrocnemius, and Longissimus dorsi muscles were weighed, as were the kidneys, spleen, liver, lungs, and heart. Proximate analyses were performed on the Longissimus dorsi muscle. Data were analyzed by analysis of variance using the MIXED procedure of SAS 9.4 (SAS Institute, Cary, NC). Day was considered a repeated measure for bodyweights and BIA measurements. Significance was determined at a P value of less than or equal to .05, and tendencies were noted when the P value was less than or equal to .10.

Results: Bodyweight did not differ among groups on day −1 or 21. Empty bodyweight did not differ between lean controls and lean heat-stressed wethers but tended to be greater (P = .06) for high-adiposity controls, high-adiposity heat-stressed wethers, and ω-3 PUFA-supplemented high-adiposity heat-stressed wethers than for lean controls. BIA-estimated fat-free soft tissue was less (P < .05) for lean heat-stressed wethers and high-adiposity controls than for lean controls. BIA-estimated fat-free soft tissue did not differ between unsupplemented and ω-3 PUFA-supplemented high-adiposity heat-stressed wethers, but BIA-estimated fat-free mass was greater (P < .05) with ω-3 PUFA supplementation. BIA-estimated mass of the combined leg, sirloin, loin, rack, shoulder, neck, riblets, shank, and lean trim was greater (P < .05) in lean controls than all other groups, except lean heat-stressed wethers. Organ weights did not differ among groups. Semitendinosus muscles were heavier (P < .05) for ω-3 PUFA-supplemented heat-stressed wethers than for all other groups. Similarly, semitendinosus weight/bodyweight and semitendinosus weight/empty bodyweight tended to be greater (P < .09) for ω-3 PUFA-supplemented high-adiposity heat-stressed wethers than unsupplemented high-adiposity heat-stressed wethers. Gastrocnemius weight/empty bodyweight and flexor digitorum superficialis weight/empty bodyweight were less (P < .05) for high-adiposity controls than for lean controls but did not differ between high-adiposity heat-stressed and lean heat-stressed wethers. Longissimus dorsi tended to be lighter (P < .05) for lean heat-stressed wethers than lean controls. Fat-to-protein ratios were lower (P < .05) in supplemented wethers compared to untreated groups, with greater protein content and reduced fat percentage (P < .05) with intervention. Longissimus dorsi protein content tended to be greater (P = .09), fat content was less (P < .05), and fat-to-protein ratio was less (P < .05) for ω-3 PUFA-supplemented high-adiposity heat-stressed wethers than for all other groups.

Conclusion: These findings demonstrate that heat stress and high adiposity impaired growth in some but not all muscles. Likewise, targeting systemic inflammation with daily dietary supplementation of ω-3 PUFA mitigated some but not all of these deficits, indicating that systemic inflammation contributes to the poor outcomes of heat stress but does not account for all deficits. Consequently, we conclude that systemic inflammation is an effective but not exclusive mechanistic target for intervention strategies to improve growth efficiency and body composition in heat-stressed livestock.

Funding Source: This research was supported by a US Department of Agriculture (USDA) National Institute of Food and Agriculture (NIFA) foundational grant (accession number 1032421), by the Nebraska Agricultural Experiment Station with funding from the Hatch-Multistate Research capacity funding program (accession numbers 1011055, 1011126) through USDA NIFA.

Keywords: hyperthermia, feedlot sheep, ω-3 PUFA, skeletal-muscle composition.

19 Effects of Chronic Heat Stress Mitigation on Finishing Beef Performance, Blood Cortisol, Microbiome, and Carcass Measures in the Southeastern United States

Clint T. Lee^*, Christina B. Welch, Dewey H. Thomas, Cameron C. Catrett, Muhammad J. Nawaz, Jordan N. Proctor, and Alexander M. Stelzleni, University of Georgia, Athens, GA 30602, USA *ctl23051@uga.edu

Introduction/Objectives: Cattle experiencing heat stress are a growing problem in the United States. Research on finishing beef cattle has focused on acute heat events; however, in the southeastern United States and other subtropical areas, livestock experience elevated heat load indices for extended periods contributing to chronic heat stress environments. Physiologic effects on productivity from heat stress can be economically devastating to livestock production systems; however, modification of the physical environment, such as improved cooling facilities, adequate shade, and nutritional management, can help alleviate the physical and physiologic impacts of heat stress. The objective of this study was to evaluate the impact of a chronic heat stress environment on animal performance, microbiome composition, blood parameters, and carcass data for beef cattle in a southeastern finishing operation. Additionally, the study aimed to assess the effectiveness of heat stress mitigation strategies, including barns, covered shelters, and fans, in improving cattle performance in feedlot settings.

Materials and Methods: Sixty Angus crossbred beef steers (374 ± 57 kg, 14–16 mo of age) from the University of Georgia (UGA) Beef Research Unit herd were blocked by weight and previous research treatment into 4 groups (n = 15). Steers within each block were randomly assigned 1 of 4 treatments: covered with fans (CWF), covered without fans (CNF), outside lot with shade (SHD), and outside lot without shade (OUT). All steers were fed, ad libitum, a total mixed finishing ration utilizing electronic feed bunks (C-Lock; Rapid City, SD) to record intake. Weight was recorded for steers on days −22, 0, 21, 42, 63, 84, and weekly thereafter until targeted terminal weight (545.5 kg) was reached. A subset of 10 steers per treatment, closest to the treatment slaughter average weight, had blood serum collected for cortisol testing on days −22, 0, 1, 3, 7, and 21. Fecal samples were collected from all steers on days −22, 0, 21, 42, 63, and 84, placed into a sterile 15-mL conical tube, flash frozen, and transferred on dry ice to a −80°C freezer. DNA was extracted from fecal samples on a subset of 12 steers per treatment and transported to Kelly Products Inc. LLC (Covington, GA) for 16S ribosomal ribonucleic acid gene sequencing. Sequencing data were demultiplexed and processed in QIIME 2, using a pretrained Naïve Bayes classifier with the SILVA assigned taxonomies with reads classified by the taxon using the fitted classifier. Once a treatment averaged the targeted finishing weight, the steers were transported (72.3 km) to the UGA Meat Science and Technology Center for slaughter under federal inspection. Twenty-four hours postmortem, carcasses were ribbed (12–13 rib juncture). Following a 30-min bloom, data were recorded for yield (hot-carcass weight, ribeye area [REA], 12th rib backfat thickness, and kidney, pelvic, heart fat) and quality (marbling score and overall maturity) determinants. Data were analyzed as a completely randomized block design utilizing Proc-MIXED (SAS, V9.4). Finishing environment and day were fixed effects, and steer within finishing environment was the random term. Means were separated using the Tukey adjustment in the PDIFF option of LSMEANS at less than or equal to 0.05.

Results: Steer weights were not different at the start of the feeding period (day 0; P > 1.0). Throughout the finishing period, treatment weights increased (P ≤ .02) within treatment and were similar within a weigh date (P > .07). However, SHD and OUT steers did not gain as much in each 21-d period and remained similar to CWF and CNF steers from the prior 21-d period. Although day 84 weights were not different (P ≥ .40) among treatments, CWF steers reached target weight first (90 d), followed by CNF, SHD, and OUT (97 d, 104 d, 111 d, respectively). There was a treatment × period interaction for average daily gain (ADG; P < .01), but no treatment or period main effect (P > .40). During period 1, CWF had greater ADG than SHD and OUT (P < .03), but, throughout period 2, CNF had greater ADG than CWF, SHD, and OUT (P < .03). During period 3, CWF and SHD exhibited similar ADG (P = .99) and gained more per day than CNF and OUT (P < .02). From day 63 to 84, OUT had greater ADG than CWF (P = .04), but all other treatment combinations did not differ (P > .07). There was no treatment × day interaction for cortisol concentration (P > .06), and the finishing environment did not impact levels (P = .92). There was a day main effect on serum cortisol concentration levels (P = .01); however, after Tukey adjustments, there were no differences. There was no treatment × day interaction (P > .08) or finishing environment main effect (P > .08) for any components of α diversity. However, days on feed impacted all components (P < .01). Observed features were greater on day −22 than all other days (P > .01), and day 0 was greater than day 21 and day 42 (P < .01). Evenness was similar from day −22 to day 0 (P = .84), but day −22 and day 0 were greater than all other days (P < .01). Afterward, day 21 was less than day 63 and day 84 (P < .01), and day 42 was less than day 63 and day 84. The Shannon index and Faith’s phylogenetic diversity followed similar trends as the observed features and evenness, where values decreased as steers were on feed from day −22 to day 0 or day 21 and then increased. No differences were found for traits related to carcass yield or quality (P > .05), except the OUT steers exhibited greater REA (P = .05) than SHD steers.

Conclusion: Although there were no differences in steer weights within feeding periods, exposed steers took 14 d and 21 d longer to reach target weight. Steers in mitigated environments had greater ADG in the first 2 periods, while OUT steers improved ADG later in the finishing period (September), which could be a compensatory response to lower heat load indices. Serum cortisol was not different in the current study and was not a good indicator chronic heat stress. α diversity was greater during the pretrial period, as cattle were on a forage-based diet. When switched to a concentrate-based diet, diversity was decreased but regulated over time back to prior levels. Confirming prior feeding trials on chronic heat stress, there were no differences comparing the carcass yield and quality measure across finishing environments. Additional studies are needed to obtain greater understanding of physiologic indicators and response to chronic heat stress in finishing cattle.

Funding Source: Georgia Agricultural Commodity Commission for Beef.

Keywords: heat stress, microbiome, feedlot, beef.

20 Reducing Escherichia coli O157:H7 and Salmonella spp. in Ground Beef With Natural Antimicrobials

Monica Morales^*, Brayan Montoya-Torres, Ariana D. Roldan, Markus Miller, and Mindy M. Brashears, International Center for Food Industry Excellence, Department of Animal and Food Sciences, Texas Tech University, Lubbock, TX 79409, USA *monica.s.morales@ttu.edu

Introduction/Objectives: Recent studies highlight the potential of natural antimicrobials, including plant-based compounds and organic acids, to reduce pathogens in beef products and meet consumer demand for cleaner labels. One such intervention, based on citric and hydrochloric acids, demonstrated effectiveness against Salmonella and Shiga toxin-producing Escherichia coli when applied to beef trimmings. Building on this, this study evaluated a cinnamon-based antimicrobial formulated as a water-based solution at 5%, 7.5%, and 10% concentrations in chilled beef trimmings inoculated with Salmonella (Enteritidis, Newport, Typhimurium) and E. coli O157:H7. Treatments were applied at ambient temperature using an agitating mixer to ensure full surface contact. Ground beef (80% lean) was stored in a retail display case at 4°C for 3 d to assess antimicrobial efficacy and potential residual effects. E. coli O157:H7 was prioritized based on Food Safety Inspection Service policy regarding adulterant serogroups. Results aim to support the application of sustainable antimicrobial strategies to enhance ground beef safety without compromising product quality.

Materials and Methods: This study evaluated the efficacy of antimicrobial treatments against Salmonella spp. and E. coli O157:H7 in beef trimmings and the resulting ground beef. Vacuum-sealed beef trimmings, confirmed negative for these pathogens, were sourced from Raider Red Meats and portioned into 50-g cubes at the Food Microbiology Laboratory at Texas Tech University. The study targeted E. coli O157:H7 due to its low infectious dose and serious health implications, and 3 Salmonella enterica serovars—Typhimurium, Newport, and Enteritidis—commonly linked to beef-related outbreaks in the United States. These strains (American Type Culture Collection references) were revived from frozen storage, cultured in brain heart infusion broth, and combined to prepare pathogen cocktails. Final concentrations were verified via plating on selective agars. Each 50-g beef cube was aseptically inoculated with 250 μL of the respective cocktail, massaged for even distribution, and held for 10 min at 25°C. Treatments were applied using a simulated agitating system with immersion at ambient temperature to ensure full surface contact. Following treatment (≤60 s), samples were ground, portioned into 400 g, packaged, and displayed in a refrigerated case simulating retail condition. Samples were collected on day 0, 1, and 3 posttreatments. From each, 10 g were homogenized in buffered peptone water and serially diluted. Enumeration was performed using XLT-4 for Salmonella and Sorbitol-MacConkey agar for E. coli O157:H7. Colonies were identified based on morphology, and counts expressed as Log₁₀ CFU/g. Data analysis included 3 biological replicates for 5 treatments: control, water, 5%, 7.5%, and 10%. Initially, linear regression assessed trends over time, but no significant changes were observed. Therefore, a 1-way analysis of variance (ANOVA; P < .05) followed by Tukey’s Honestly Significant Difference test was used to evaluate differences among treatments.

Results: Initial E. coli O157:H7 counts in the control and water-treated samples exceeded 8.0 Log₁₀ CFU/g. While the water treatment showed a slight reduction over time, it was not statistically significant (P > .05). Significant reductions were observed on day 0 for all cinnamon-based treatments: 1.34 log (5%), 1.30 log (7.5%), and 1.64 log (10%) (P < .05). These reductions remained evident on day 1, with the 10% and 5% treatments achieving 2.04 and 1.31 Log₁₀ CFU/g reductions, respectively. By day 3, the reductions were still significant, although slightly lower. Across all days, the 10% treatment consistently resulted in the greatest reduction. Despite some variability, all antimicrobial treatments performed significantly better than the control and water. Since reductions occurred mainly on day 0 and did not significantly improve over time, the time factor was removed from the statistical model. The ANOVA results confirmed significant differences among treatments (P < .001), and pairwise comparisons showed all treatments were statistically different from the control and water (P < .002). No residual antimicrobial effect was observed beyond the initial application, and there was no pathogen recovery over the 3-d period. These findings suggest the cinnamon-based antimicrobial is effective when applied to beef trimmings before grinding. In the case of Salmonella, no significant differences were observed between control and water treatments, confirming that pathogen reduction was not due to mechanical rinsing. Initial counts for the control were around 8.84 Log₁₀ CFU/g, while the water treatment showed minimal change. Significant reductions were noted for the 5%, 7.5%, and 10% treatments, particularly on day 0, with reductions of 1.23, 1.11, and 1.54 Log₁₀ CFU/g, respectively (P < .05). Similar reductions persisted through day 3, with the 10% treatment maintaining the highest efficacy. Again, due to the absence of significant reductions over time within each treatment, the time factor was excluded. The ANOVA confirmed significant differences (P = .0039), supporting the antimicrobial’s effectiveness. The reductions were attributed to the active ingredient rather than physical removal by water, demonstrating its potential as a viable intervention to control Salmonella in ground beef. Together, the findings support the use of this cinnamon-based treatment as a practical, natural antimicrobial intervention in beef processing, with consistent effectiveness against both E. coli O157:H7 and Salmonella spp.

Conclusion: This study demonstrated that a cinnamon-based natural antimicrobial effectively reduced E. coli O157:H7 and Salmonella in ground beef immediately after application. Treatments at 5%, 7.5%, and 10% concentrations all showed significant reductions, with the 10% being the most effective. These results support its potential as a practical intervention in meat processing. The findings align with previous research emphasizing the value of natural antimicrobials in replacing synthetic preservatives, contributing to cleaner-label food production. While no residual antimicrobial effect was observed, this does not diminish its relevance. Instead, it confirms the treatment’s role as an immediate pathogen reduction strategy, particularly before retail distribution. Given that cold storage and other controls remain essential, the application of this antimicrobial can be seen as a complementary safety measure. Overall, the treatment offers a promising solution to enhance ground beef safety, meeting both consumer demand for natural products and industry needs for effective microbial control.

Funding Source: International Center for Food Industry Excellence, Texas Tech University.

Keywords: ground beef, natural antimicrobial, safety.

21 Impact of L-Arginine Concentration on the Growth of Clostridium sporogenes in Restructured Hams

Laura Reiling^*, Mansour Alnajrani, Gage Walsh, Sapna Dass, and Wesley N. Osburn, Department of Animal Science, Texas A&M University, College Station, TX 77843, USA *lreiling35@gmail.com

Introduction/Objectives: Regulatory bodies in the United States have proposed changes to the labeling regulations of naturally cured processed meat products to prohibit the phrases “uncured” or “no nitrate or nitrite added.” As such, interest in alternative curing systems without the addition of nitrite has grown. However, given that nitrite functions as an antimicrobial agent against Clostridium botulinum and Clostridium perfringens, the removal of nitrite/nitrate from curing systems raises food safety concerns. Therefore, the objective of this study was to determine how the generation of nitric oxide (NO) from the endothelial NO synthase system with varying L-arginine concentrations impacts the growth and recovery of Clostridium sporogenes, a surrogate organism for C. botulinum, in restructured hams.

Materials and Methods: Restructured hams were manufactured utilizing pork sirloin muscle and a 20% brine composed of salt (9%), sugar (5.75%), sodium tripolyphosphate (1.75%), sodium erythorbate (0.547 ppm), and L-arginine-hydrochloric acid at concentrations of 1000 ppm to 5000 ppm or a sodium nitrite control (200 ppm) as the curing agent. The hams were inoculated with C. sporogenes, as a surrogate organism for C. botulinum, prior to cooking the treatment and control hams to 71.1°C and chilling to 4°C. Hams were vacuum packaged and stored under refrigeration (4.4°C) and subsequently analyzed on days 1, 28, and 56 of storage for water activity, pH, and bacterial growth on both Clostridium isolation agar (CIA) and tryptic soy agar (TSA). An analysis of variance (ANOVA) and Tukey’s Honestly Significant Difference test were run to determine if a significant difference was present for water activity and cooked pH values. A χ² test for independence was run to determine if a significant association between 2 categorical variables existed (L-arginine concentration, day, thermal processing, ingredient, growth percentage).

Results: Although growth was observed in some samples, the number of colonies was insufficient to meet the criteria for countable plates (25–250 CFU/plate) and thus could not be reliably quantified. Results showed a significant association (P < .05) between storage day and the percentage of CIA and TSA plates with growth in the cooked L-arginine-treated samples. Still, they showed similar growth percentages to the nitrite control. To determine if a significant association between cure ingredients existed, L-arginine-treated samples and the nitrite control were analyzed together. No significant association (P > 0.05) was detected between the cooked L-arginine-treated hams and the nitrite control in either medium (CIA or TSA), therefore suggesting that L-arginine and nitrite were comparable in preventing bacterial growth. No significant association (P > .05) between L-arginine concentrations and bacterial growth percentage was observed in either medium (CIA or TSA). However, 1000 ppm to 3000 ppm had a slightly higher percentage of plates with no growth (83%), compared to 4000 ppm and 5000 ppm (68%), suggesting that these lower concentrations are sufficient for preventing bacterial growth. While growth was observed in the cooked ham samples on CIA media, bacterial morphology did not match the morphology of the pure C. sporogenes strain or the raw ham samples. Sequencing results revealed that the microorganisms growing were Carnobacterium maltaromaticum, an anaerobic lactic acid bacterium commonly found in meat.

Conclusion: This suggests that L-arginine concentrations of 1000 ppm to 3000 ppm are adequate to prevent the growth of C. sporogenes on CIA plates. While growth was observed on the cooked ham CIA samples, DNA sequencing revealed that it was not Clostridial growth but was the bacterium C. maltaromaticum. Additionally, no antimicrobials were added to any treatment or control hams. Therefore, we conclude that at least 1000 ppm L-arginine concentration is comparable to the nitrite control (200 ppm) in inhibiting the growth of C. sporogenes in restructured hams thermally processed to 71.1°C, held up to 56 d of vacuum-packaged, refrigerated storage.

Funding Source: US Department of Agriculture, National Institute of Food and Agriculture’s Agriculture and Food Research Initiative grant number 2021-09606.

Keywords: endothelial NOS, L-arginine, Clostridium.

22 L-Arginine Concentration, Curing Method, and Location Impact on Endothelial Nitric Oxide Enzyme in Pork Bacon

Gage Walsh^*, Tanner Wright, Mansour Alnajrani, Nicholas Broz, Augustus Harrison, Arlie Reeves, Laura Reiling, and Wesley N. Osburn, Department of Animal Sciences, Texas A&M University, College Station, TX 77843, USA *grw1375@tamu.edu

Introduction/Objectives: This study aimed to evaluate the effects of different L-arginine concentrations, curing methods, and anatomical pork belly locations on the efficiency of endothelial nitric oxide synthase (eNOS) in pork bacon manufacturing. Specifically, the research sought to determine whether eNOS could be an effective alternative curing system by generating nitric oxide (NO), which contributes to the cured meat characteristics typically provided by nitrite.

Materials and Methods: Six pork bellies were divided into 3 anatomical sections (anterior, middle, and posterior) and treated with a 10% brine solution consisting of salt, sugar, phosphate, sodium erythorbate, and either 1000 ppm or 3000 ppm of L-arginine. A nitrite control (120 ppm) was also included for comparison. The curing process was performed either by injection or vacuum tumbling. Samples were injected via a 4-needle head hand injector. Vacuum tumbled samples were double bagged in sealed vacuum bags and tumbled for 2 h at 20 psi and 6 rpms. After curing, the bellies were heat treated to 56.8°C, chilled, sliced, vacuum packaged, and stored at 4°C. Analyses were conducted on days 1, 28, and 56 of shelf life. The parameters measured included residual nitrate RnO₃, residual nitrite RnO₂, 2-thiobarbituric acid reactive substances (TBARS), pH water activity, cooking yield, and nitrosyl hemochromogen (NO-heme) values to assess lipid oxidation, cured meat color, and overall product quality. This study was a factorial (2 concentrations × 3 belly locations × 2 curing methods) plus 1 nitrite control randomized block design and was replicated 3 times (n = 18). Least-square means and Tukey’s Honestly Significant Difference test were conducted with a P value of less than .05 significance. The nitrite control served as a reference and was statistically analyzed independently.

Results: Curing method (P = .02) impacted TBARS values with injected samples having higher values (0.13 mg/kg) than tumbled (0.11 mg/kg). Day (P < .0001) impacted TBARS values with values increasing from day 7 (0.095 mg/kg) and day 28 (0.11 mg/kg) to day 56 (0.16 mg/kg). Curing method (P < .0001) impacted cooking yield with injected samples having higher yields (100.91%) than tumbled samples (95.95%). Day (P < .01) impacted RnO₃ with day 28 values (4.86 ppm) being lower than day 1 (8.48 ppm) and day 56 (8.52 ppm). Concentration impacted RnO₂ values with 1000 ppm arginine values (1.29 ppm) being higher than 3000 ppm arginine values (1.01 ppm). Concentration impacted NO-heme values with 1000 ppm arginine values (6.59 ppm) being higher than 3000 ppm arginine values (5.68 ppm). The results revealed statistically significant differences (P < .05) across the main effects in RnO₃, RnO₂, TBARS, and NO-heme values, though the practical impact was minimal, with differences of less than 1.0 ppm. The L-arginine-treated samples showed approximately one-third of the NO-heme (≈6 vs. 18 ppm) and RnO₃ (≈7 vs. 24 ppm) levels compared to the nitrite control, and the RnO₂ values in the nitrite control were significantly higher than in the L-arginine samples (≈1 vs. 37 ppm). Increasing L-arginine concentrations from 1000 ppm to 3000 ppm did not result in greater NO production, indicating that the higher concentration did not enhance eNOS activity.

Conclusion: These findings suggest that eNOS can produce sufficient NO to generate some cured meat characteristics, including color and antioxidant properties, in pork bacon. However, the eNOS system does not perform at the same level as traditional nitrite curing, as evidenced by the lower NO-heme, RnO₃, and RnO₂ values.

Funding Source: Internal funding.

Keywords: meat processing, alternative curing.

23 Hop Products Inclusion in Fresh Beef Patties Decreased Aerobic Microbial Count, Reduced Lipid Oxidation, and Improved Subjective Color Scores

Corbin R. Fornes^*, Yufei Guo, Claire Shaw, Parastoo Ebrahimi, Tara Goertzen, Jessie Van Buren, James A. Nasados, Phillip D. Bass, and Michael J. Colle, University of Idaho, Moscow, ID 83844, USA *forn1107@vandals.uidaho.edu

Introduction/Objectives: The addition of functional ingredients in meat can improve shelf-life characteristics, such as decreasing microbial growth, decreasing lipid oxidation, and improving color. This study utilized hop extracts as functional ingredients. Hop extracts contain flavonoids and phenolic compounds, both of which exhibit antioxidant and antimicrobial properties. The objective of this study was to improve the shelf life of beef patties by using commercially available hop extracts as natural functional ingredients without impacting consumer sensory characteristics.

Materials and Methods: Hop extract treatments included: control (no extract added), 5 ppm, 10 ppm, and 20 ppm dry hop extract, as well as 111 ppm aqueous hop extract. Six batches of each treatment were made at Vandal Brand Meats using US Department of Agriculture choice boneless beef chuck shoulder clods (IMPS #114) purchased from a commercial processing facility and wet aged for 13 d. Each batch included 4.53 kg ground beef, 15% water, 1% salt, 0.2% onion granules, and the designated hop extract treatment. Beef chucks were coarse ground through 10-mm plate, and fine ground through 3-mm plate, mixed for 2.5 min at 29 rpm using DMX-50 Daniels 50 Lb. mixer, and formed using a Patty-O-Matic 220A patty former into 16-mm thick patties. The lean-to-fat ratio was analyzed and measured at 83 to 17, and each patty weighed 151 g. Two patties from each batch were analyzed for each parameter, except for sensory where 3 patties were used. Retail fluid loss percentage was calculated using patty weight on day 0 and patty weight following 4 d of retail display. Lipid oxidation was measured using a thiobarbituric acid reactive substances (TBARS) assay on raw beef patties on days 0, 2, and 4. Subjective and objective color measurements were taken once daily (days 0–4) during retail display, and then patties were systematically rotated after measurement. Aerobic microbial count was measured on days 0, 2, and 4 and incubated for 48 h minus or plus 3 h at 30°C minus or plus 1°C. Sensory was conducted on day 1 of retail display and utilized 84 panelists, analyzing overall acceptability. Data were analyzed using a linear model by looking at retail fluid loss, aerobic microbial count, lipid oxidation, subjective color, objective color, and consumer sensory in R program version 4.3.3. Retail display day, hop extract treatment, and their interaction were assumed as fixed effects with retail display day considered a repeated measure, and batch was considered a random effect, with a significance level of a P value less than .050.

Results: There was no significant difference between treatments in retail fluid loss (P = .484). Aerobic microbial count had a treatment by day interaction (P = .034), where patties treated with 20 ppm on day 0 started and ended with the lowest aerobic microbial count. The patties treated with 111 ppm had the highest count and by day 2 became similar to the other treatments and remained similar until day 4. Lipid oxidation had a treatment by day interaction (P < .001) where the patties treated with 111 ppm on day 0 started with less lipid oxidation, and on day 4 patties treated with 10 ppm and 111 ppm both had less lipid oxidation when compared to the other treatments. Subjective color also experienced a treatment by day interaction (P = .025): the patties treated with 111 ppm had more dull red color on day 0 and by day 4 had a brighter red color when compared to the other treatments. Conversely, the control patties treated with 5 ppm started with a brighter red color on day 0 and by day 4 had a duller red color when compared to the other treatments. Objective color had no treatment by day interaction in L* (P = .934) or in b* (P = .137), but L* differed between treatments (P < .001). For objective color, there was a treatment by day interaction in a* (P = .004). On day 0 the hop extracts reduced the amount of redness in beef patties, but by day 4 of retail display all treatments became similar. In consumer sensory testing, there was no significant difference for overall acceptability (P = .960), tenderness (P = .746), juiciness (P = .725), or flavor (P = .929).

Conclusion: The dry hop extract treatments decreased aerobic microbial count without impacting consumer sensory characteristics, while the liquid hop extract reduced lipid oxidation during early retail display and improved subjective color scores without impacting consumer sensory characteristics. However, the 20 ppm and 111 ppm treatments reduced redness in beef patties during early retail display. In beef patties, hop extracts have the potential to reduce waste by extending shelf-life parameters while maintaining a clean label. Future avenues to further research include increasing the concentrations of the hop extracts, mixing dry and aqueous hop extracts, determining the effect of freezing and thawing on beef patties containing hops extract, and evaluating the efficiency of a hop extract patty that has been stored for an extended period.

Funding Source: BetaTec.

Keywords: hop extract, functional ingredient, beef.

24 Structural and Physicochemical Evaluation of Hybrid Pork Bologna Developed With Faba Bean Protein Isolate Stabilized Canola Oil-in-Water Nanoemulsion Gel as a Novel Fat Replacer

Oluwafemi J. Coker^*, Supratim Ghosh, and Phyllis Shand, Department of Food and Bioproduct Sciences, University of Saskatchewan SK S7N 5A8, Canada *oluwafemi.coker@usask.ca

Introduction/Objectives: Developing healthier meat products has gained significant attention because of increasing consumer awareness of dietary health and wellness. This study investigates the structural and physicochemical attributes of hybrid pork bologna formulated with a faba bean isolate (FBI) stabilized nanoemulsion gel as a novel fat replacer. Traditional processed meats, such as bologna, are often high in saturated fats that are linked to various health concerns. The use of nanoemulsion gels offers a promising solution by mimicking the texture, mouthfeel, and stability of fat while improving the overall lipid profile. Developed hybrid bolognas were characterized to ensure that the fat replacement did not compromise product quality. Additionally, the nutritional profile was analyzed to assess potential health benefits, such as calorie content and fatty acid composition. By integrating innovative food nanotechnology, this study contributes to developing sustainable and healthier meat products that meet consumer expectations for taste and texture while addressing dietary health concerns.

Materials and Methods: Pilot scale nanoemulsion gels were prepared using a microfluidizer and consisted of 59.5% water, 30% canola oil, 8.5% FBI, and 1.96% salt. Four distinct bologna formulations, full fat (FFB), low fat (LFB), heated protein emulsion hybrid (HP-hybrid), and unheated protein emulsion hybrid (UP-hybrid), were developed to evaluate fat replacement strategies. The target fat levels were 20% and 10% for FFB and LFB, HP- and UP-hybrids, respectively. Fresh pork leg meat was trimmed of connective tissue and excess fat, coarsely ground through a 12.7-mm plate, vacuum sealed, and stored at −30°C. Before processing, frozen meat was thawed at 1°C, reground through a finer 4.76-mm plate, and back fat was similarly processed. For hybrid formulations, frozen nanoemulsion gels (heated or unheated protein) were manually crumbled into a chopper to integrate with the meat matrix. The meat emulsion preparation began by blending lean meat with dry ingredients, salt, Prague powder (6.4% sodium nitrite), sodium tripolyphosphate, and sodium erythorbate in a bowl chopper (Hobart model, #8418D). Ice water was gradually incorporated during initial chopping (speed #1, 1 min). For FFB and LFB, pork back fat was added, while HP- and UP-hybrids received their respective emulsion gels during high-speed chopping (speed #3, 2 min). The batters underwent dual-pass emulsification via an emulsion mill. After vacuum tumbling to eliminate air pockets (vacuum pressure > 27 mmHg) for 1.5 min to 2 mins, approximately 1 kg of batter was stuffed into waterproof casings (63-mm diameter) using a hydraulic stuffer (EI-20 model) and sealed with cotton string. Stuffed chubs were refrigerated overnight at 1°C before cooking. A 5-stage thermal protocol (40–72°C) in an air-agitated water bath (∼200 L) was used. The bolognas were evaluated for microstructural (scanning electron microscopy [SEM] and Synchrotron-based X-ray micro-computed tomography [SR-μCT] phase contrast imaging), expressible moisture via centrifugation, textural (texture profile analysis [TPA] and torsional gelometry), and nutritional fatty acids profile properties. All experiments were conducted in triplicate. The data were analyzed using analysis of variance with a significance level of a P value less than .05, and mean separation was done using the Duncan multiple range test. The statistical analysis was done using SPSS software (v. 28).

Results: SEM analysis revealed distinct structural differences between control and hybrid bologna formulations. FFB and LFB bolognas exhibited smooth, continuous surfaces with visible white regions that indicated pork backfat distribution (Figure 1). In contrast, hybrid samples (HP- and UP-hybrids) displayed rough microstructures marked by cavities, likely caused by the dispersion of water, protein, or air during lyophilization. Notably, hybrid bolognas demonstrated improved uniformity in oil droplet distribution within the protein matrix, suggesting enhanced structural integration of the nanoemulsion gel. The reconstructed SR-μCT scans (Figure 2) revealed that the HP-hybrid and UP-hybrid bologna had the lowest oil volume fractions and the smallest fat globule size (lowest amount of free oils). This result further confirms the water-holding capacity (WHC; expressible moisture and cook loss) of the bolognas (Figure 3). It was observed that the hybrid bolognas have lower fluid release, hence a better WHC compared to the control (LFB). Torsional gelometry tests showed no significant differences in shear strain across samples. However, shear stress at fracture varied significantly (P < .05), with FFB requiring the highest shear stress (tough texture), while LFB exhibited a rubbery texture. Hybrid bolognas displayed intermediate properties, balancing toughness and rubberiness. TPA further highlighted that hybrid formulations achieved higher hardness values (P < .05) compared to controls, attributed to the stabilizing effect of nanoemulsion gels (Figure 4A). Adhesiveness was highest in FFB, whereas hybrid samples showed superior cohesiveness, outperforming LFB. These textural shifts underscore the functional role of protein emulsion gels in mimicking fat while enhancing structural resilience. Nutritionally, replacing pork fat with nanoemulsion gels drastically alter fatty acid profiles (Figure 4B). Saturated fatty acids (SFA) myristic (C14:0), palmitic (C16:0), and stearic (C18:0) acids were reduced by about 73% in hybrids. Conversely, monounsaturated fatty acids, particularly oleic acid (C18:1 c9), increased to about 60% of the total fat content compared to 39 % in LFB. Polyunsaturated fatty acids (PUFA) also increased, with linoleic acid (C18:2 c9, c12 n6) reaching about 16%, and minor PUFA fractions (e.g., α-linolenic, eicosatrienoic, and arachidonic acids) showing higher concentrations in hybrids than controls. This shift aligns with health-driven objectives to reduce SFA and enhance heart-healthy unsaturated fats.

Conclusion: This study demonstrates the successful development of hybrid pork bologna using heated or nonheated protein nanoemulsion gels as innovative fat replacers, offering a promising pathway to healthier processed meats. It was observed that the structural networks influenced the textural and water-holding properties, while the nutritional evaluations revealed that hybrid formulations effectively reduced SFA by approximately 73% and enriched mono- and polyunsaturated fats, aligning with dietary recommendations for cardiovascular health. Despite a rougher microstructure observed via SEM, hybrid bolognas maintained enhanced textural properties, including higher hardness and cohesiveness, outperforming LFB controls and bridging the gap between rubbery and tough textures. The integration of nanoemulsion technology not only addresses nutritional concerns but also preserves functional integrity, proving that fat reduction need not compromise texture or consumer satisfaction. Although the preliminary sensory acceptance is promising, there is a need to evaluate the sensory attributes of the bologna to meet the consumer’s expectation.

Figure 1.

Effect of different fat levels and 12.5 weight percentage faba bean isolate stabilized 20 weight percentage canola oil-in-water emulsion gels on the microstructure. (A) Full fat, (B) low fat, (C) UP-hybrid, and (D) HP-hybrid of cooked bologna. Scale 250 μm. HP-hybrid, heated protein emulsion hybrid; UP-hybrid, unheated protein emulsion hybrid.

Figure 2.

Synchcrotron X-ray computed tomography of 3-dimensional rendering of oil droplets in (A) full fat, (B) low fat, (C) unheated protein emulsion hybrid, and (D) heated protein emulsion hybrid bologna samples. Yellow spots represent animal fat, blue represents water, grey represents oil droplets, and green represents protein matrix.

Figure 3.

Effect of different fat levels 12.5 weight percentage faba bean isolate stabilized 30 weight percentage canola oil-in-water emulsion gels on (A) expressible moisture, (B) cook loss, and (C) hardness. Data points represent an average of n = 3. Bars with different letters indicate significant difference (P < .05). HP-hybrid, heated protein emulsion hybrid; UP-hybrid, unheated protein emulsion hybrid.

Funding Source: Ministry of Agriculture, Government of Saskatchewan, Natural Sciences and Engineering Research Council of Canada, and SaskCanola.

Keywords: hybrid bologna, structure, physicochemical, nanoemulsion, canola oil.

25 Use of Nitrate/Nitrite and Food-Grade Coatings to Control Tyrophagus putrescentiae via Nitric Oxide Formation During Dry-Cured Ham Processing

Sawyer Wyatt Smith^1,*, Xue Zhang², Guyue Tang², Ryen Comey¹, Daniel Joyce¹, Vada Lee Thacker¹, Thomas Phillips³, and Wes Schilling¹, ¹Department of Biochemistry, Nutrition, and Health Promotion, Mississippi State University, Starkville, MS 39762, USA, ²Department of Animal and Dairy Sciences, Mississippi State University, Starkville, MS 39762, USA, ³Department of Entomology, Kansas State University, Manhattan, KS 66506, USA *ssmith@foodscience.msstate.edu

Introduction/Objectives: Dry-cured ham is highly susceptible to infestations by the ham mite, Tyrophagus putrescentiae, during the aging process. During dry-cured ham processing, hams are cured with sodium nitrite (625 ppm) and sodium nitrate (2187 ppm), which delay lipid oxidation, stabilize color, act as antimicrobial agents, and enhance flavor. Nitric oxide (NO) produced during curing plays a crucial role in color development (nitrosyl hemochrome) and antimicrobial properties. Research by Yang et al. (2022) demonstrated that NO fumigation can achieve 100% control of ham mite infestations. Increasing sodium nitrite and nitrate concentrations during ham processing could elevate NO levels, potentially enhancing mite control within an industrial aging facility. This study aimed to evaluate the effect of increased sodium nitrite and nitrate concentrations on mite growth and reproduction during dry-cured ham processing and to assess the effectiveness of netting used during aging.

Materials and Methods: A 5 × 2 factorial arrangement within a randomized complete block design with 2 replications was used to evaluate the effects of cure mix concentration and netting type on mite growth and reproduction. The control cure mix consisted of 6.25% salt, 0.14 % sucrose, 625 ppm sodium nitrite, and 2187 ppm sodium nitrate. The treatments consisted of the negative control (0X), control (1X), double (2X), triple (3X), and quadruple (4X) the concentration of sodium nitrite and nitrate levels of the control hams. The 2 types of netting consisting of 1) an uncoated ham net typically used for aging and 2) ham net coated with a solution of 1% carrageenan + 1% propylene glycol alginate + 40% propylene glycol (PG-coated; White et al., 2023). At a commercial country ham processing facility, hams (n = 40) were assigned to 1 of 5 cure mixes (0X, 1X, 2X, 3X, 4X), hand-coated, and stored at 2°C to 4°C for 40 d. After curing, hams were stored at 15°C for 14 d for salt equalization. Following equalization, half of the treated hams were assigned to 1 of 2 aging rooms (blocks), and, within each block, hams were further divided into 2 groups based on the netting used (PG-coated or uncoated). For experiment 1, after 6 mo and 7.5 mo of aging, respectively, hams were observed for presence, infestation severity, and overall coverage of the hams by T. putrescentiae at the commercial aging facility. Following examination(s), hams were sliced into 2.54-cm thick slices for further analysis. For experiment 2, 20 mixed-sex ham mites were inoculated onto 2.5-cm × 2.5-cm × 2.5-cm ham samples (n = 5/treatment/replication) incubated in ventilated jars at 23°C for 14 d. After the 14-d incubation, mobile mites were counted under a stereo microscope to observe mite growth and reproduction. For experiment 3, the residual levels of sodium nitrite were determined spectrophotometrically using a Griess reagent system at 25°C and 535 nm wavelength.

Results: Results for experiment 1 indicated that hams aged for 6 mo had a significantly lower (P = .0455) mite presence than hams aged for 7.5 mo across all treatments, apart from the controls (0X, 1X), which exhibited no difference between aging times. Netting type significantly impacted (P < .0001) the effectiveness of the treatments. When uncoated nets were used, elevated nitrite and nitrate treatments were efficacious in lowering mite presence, whereas 2X, 3X, and 4X had lower (P < .001) mites’ presence than the control (0X, 1X)—albeit no differences existed among the treatments (P > .05). When PG-coated nets were used, treatments did not exhibit any differences (P > .05) with respect to mite presence. Results from the reproduction study in experiment 2 indicate that after 6 mo of aging all treatments were ineffective at controlling mite growth and reproduction, all resulting in average counts greater than 20. Only the 4X level significantly differed (P = .0024) among the treatments, whereas it had even greater levels of mite growth and reproduction. Netting type had no impact on mite growth and reproduction (P = .3192). In the final experiment, residual levels of nitrite were compared among the treatments. After 6 mo of aging, 4X had the highest (P > .05) concentration of residual nitrite (68.5 ppm), followed by 3X (44.8 ppm), 1X (39.5 ppm), and 2X (23.2 ppm). The negative control (0X) readings were below the limit of detection. Likewise, all treatments from 7.5 mo were below the limit of detection, which is likely due to the added nitrite being fully converted to NO.

Conclusion: Although treatments of elevated nitrite and nitrate levels, in tandem with netting type, exhibited some impact on mite presence at the aging facility, the extent of control in comparison to potential costs is insufficient to be recommended as a viable part of an integrated pest management system.

Funding Source: This work was supported by competitive grants received from the US Department of Agriculture National Institute of Food and Agriculture’s Methyl Bromide Transition program (award number 2015-51102-24143) and the Division of Agriculture, Forestry, and Veterinary Medicine at Mississippi State University.

Keywords: mites, dry-cured ham, nitrite curing.

26 Incorporation of Dietary Fiber Compounds in Meat Batters

Milena Conte^*, Yifei Wang, and Benjamin M. Bohrer, Department of Animal Sciences, The Ohio State University, Columbus, OH 43210, USA *conte.95@osu.edu

Introduction/Objectives: The inclusion of dietary fiber in formulated foods could enhance their nutritional profile, promoting digestive health and reducing risks of chronic disease. Since changing consumer eating behavior is challenging, developing innovative fiber-rich products is essential, particularly in popular foods like processed meats. However, limited research has focused on investigating dietary fiber as an ingredient in processed meats. The objectives of this research were to investigate the influence and effectiveness of 3 novel dietary fiber compounds (red seaweed, ground psyllium husk, and ground chia seeds) on physicochemical properties of comminuted meat models. The hypothesis is that 1 of the selected dietary fiber compounds, or a combination, will have the appropriate technological properties for being effectively integrated in the processed meat systems while limiting negative physiochemical effects when compared with traditional processed meat products.

Materials and Methods: Emulsion batters were formulated to test the inclusion of 3 ingredients with notable dietary fiber content (red seaweed [59 g dietary fiber/100 g], psyllium husk [80 g dietary fiber/100 g], and ground chia seeds [42 g dietary fiber/100 g]), with total inclusion of 1% of each ingredient. Treatments were the following: a control treatment without addition of fiber (CON), 1% inclusion of seaweed (SEA), 1% inclusion of psyllium husk (PSY), 1% inclusion of ground chia seeds (CHIA), 0.5% inclusion of seaweed and psyllium husk (SEA_PSY), 0.5% inclusion of seaweed and ground chia seeds (SEA_CHI), 0.5% inclusion of psyllium husk and ground chia seeds (PSY_CHI), and 0.33% inclusion of seaweed, psyllium husk, and ground chia seeds (SEA_PSY_CHI). The formulations consisted of lean ground beef (67%), pork backfat (10%), sodium chloride (1.64%), tripoly phosphate (0.35%), water/ice (20%), sodium erythorbate (0.05%), sodium nitrite (to provide ∼120 ppm), and the test ingredients (1%). Each of the 8 treatments were replicated using the same ingredients on 3 different days over a 3-wk time period (n = 3 replicates/treatment). The ingredients were prepared in batch sizes of 500 g using a commercial food blender until a homogenous batter was formed. pH and instrumental color were evaluated for the uncooked batter. In addition, rheology was performed for uncooked samples using a dynamic rheometer equipped with parallel-plate geometry. Two temperature sweeps were evaluated, from 20°C to 72°C and 72°C to 20°C, both at a rate of 1.5°C/min. Conical polypropylene 50 mL tubes were filled with meat batters and placed in a preheated water bath set at 80°C and cooked to an internal temperature of 72°C. Cooking loss was assessed after tubes were cooled. Instrumental color was also evaluated on the cooked surface and internal slices of the cooked meat batters. Texture profile analysis was measured for the cooked meat batters. Samples were compressed twice to 50% of their original height during the test. Response variables were analyzed as a randomized complete block design in PROC GLIMMIX of SAS with treatment serving as the fixed effect and block serving as a random effect.

Results: The addition of the fiber compounds did not influence (P ≥ .17) instrumental color of uncooked meat batters. Yet, there was a treatment effect (P < .05) for instrumental color for the cooked (surface) and internal slices. Cooked surface L* was affected by treatment (P = .05) with the SEA_CHI treatment (67.02 U) displaying greater L* (P < .05) compared with PSY (65.25 U) and CHI (65.53 U) treatments, while other treatments were not different and at intermediate values. Total color change (ΔE*ab) of the internal slices was affected by treatment (P = .02) with the SEA_CHI treatment and the SEA_PSY_CHI treatment having greater (P < .01) color change compared with the CHI, SEA_PSY, and PSY_CHI treatments. There were no treatment effects (P = .08) for cooking loss, and treatments had cooking loss values under 0.70% indicating appropriate emulsion stability and ability to retain water and fat during thermal processing. The pH values of the batters ranged from 5.86 to 6.00, yet no treatment effect (P > .43) was observed. Hardness was affected by treatment (P = .001), with treatments containing 1.0% and 0.5% seaweed (SEA and SEA_PSY) having the greatest levels of hardness and significantly differing from the CON, PSY, CHI, PSY_CHI, and SEA_PSY_CHI treatments. In accordance with these results, storage modulus values (G') at the peak temperature of 72°C for the SEA and SEA_PSY had the greatest numerical values. However, these values were not different (P > .05) from the CON treatment. In fact, storage modulus values (G') at the peak temperature of 72°C were lowest for the SEA_CHI treatment, which were statistically different (P < .05) from the CON, SEA, PSY, and SEA_PSY treatments. This result shows ground chia seeds negatively impacted the dynamic rheology properties, thus changing the viscoelastic characteristics during gel formation.

Conclusion: The results of this study demonstrate that dietary fiber ingredients have a potential to be effectively incorporated into meat batters without negatively impacting physicochemical properties such as pH and cooking loss. In addition, when proper combinations are used, impacts to cooked product color, texture, and gel formation can be minimized or even completely mitigated. Specific findings from this study show that formulations with greater than 0.5% red seaweed created greater levels of textural hardness, and formulations containing ground chia seeds, in combination with other fiber compounds, exhibited weaker gel structures, indicating limitations in the protein-polysaccharide complex and their application in processed meat systems. Overall, these results provide a foundation for the development of fiber-enriched processed meats that maintain desirable structural and physicochemical characteristics while potentially offering nutritional benefits. Further investigation into the inclusion levels of these ingredients and descriptive sensory analysis is necessary.

Funding Source: Funding for this project was provided by The Ohio State University Department of Animal Sciences.

Keywords: seaweed; psyllium husk; chia seeds.

27 Influence of Pulsed Electromagnetic Field Therapy on Color and Tenderness of Beef

Sydni E. Lammers^*, Haley R. Mouser, Kylie N. Krueger, Judson K. Grubbs, Keith R. Underwood, Christina E. Bakker, and Amanda D. Blair, South Dakota State University, Brookings, SD 57007, USA *sydni.borders@sdstate.edu

Introduction/Objectives: Pulsed electromagnetic field (PEMF) therapy is a tool used in livestock and human health to increase muscle metabolism thus promoting healing and reducing inflammation. When animals are harvested, muscles continue to undergo anaerobic metabolism early postmortem in attempt to maintain homeostasis. Alterations to this process with PEMF therapy have the potential to influence processes integral to the development of meat color and tenderness. We hypothesize that the application of PEMF technology will activate proteolytic enzymes in earlier postmortem, thus accelerating the aging process, and create a brighter lean color at 24 h postmortem. This technology has proven to be effective in increasing muscle metabolism in living animals; however, little research has been conducted on its potential to affect postmortem muscle metabolism and subsequent meat quality attributes of beef. Therefore, the objective of this study is to determine the influence of PEMF application on objective color and tenderness development of beef products.

Materials and Methods: Beef cattle (n = 20) harvested in northeast Iowa were selected based on a common hot-carcass weight (406 ± 5.8 kg) and quality grade (US Department of Agriculture, Choice). After carcass splitting and prior to cooler entry, PEMF treatment (PEMF Complete©) was applied to the loin on the right side of each carcass at 60 Hz and 230 V for 5 min. The left side did not receive PEMF treatment and served as the control. Instrumental color (L*, a*, b*) was recorded 24 h postmortem on the exposed ribeye surface, and ultimate muscle pH was recorded on the striploin 3 d postmortem. The striploin (m. Longissimus lumborum) from both sides of each carcass were collected and transported to the South Dakota State University Meat Laboratory. Striploins were fabricated into 2.54-cm steaks and assigned to 1 of 4 aging periods (1, 3, 7, or 14 d) with 1 steak assigned per aging period for Warner-Bratzler shear force (WBSF) analysis. Steaks were vacuum sealed and aged at 4°C then frozen on their respective aging day. After freezing, steaks were removed and thawed at 4°C for 24 h. Following thawing, steaks were cooked on a flat-top grill to an internal temperature of 40°C, then flipped, and continued cooking until reaching an internal temperature of 71°C. Percentage of cook loss was determined by weighing steaks before and after cooking. Following cooking, steaks were chilled to 4°C and then equilibrated to room temperature. Six cores were removed from each steak parallel to muscle fiber direction and sheared perpendicular to fiber orientation using a texture analyzer (Shimadzu, model EZ SX; Suzhou Instruments Manufacturing, Co., LTD, Jiangsu, China). Peak force was recorded and averaged across all 6 cores for statistical analysis. Data were analyzed using the MIXED procedure of SAS (SAS Institute, Cary, NC). Instrumental color and pH were analyzed as a randomized complete block design with carcass as the block and treatment as a fixed effect. Shear force and cook loss data were analyzed as repeated measures with peak temperature as a covariate and aging day, treatment, and their interaction as fixed effects.

Results: Application of PEMF treatment did not influence (P > .05) instrumental color (L*, a*, b*), evaluated 1 d postmortem. Mean L*, a*, and b* values for the treatment and control carcass sides were 41.16 and 41.10 plus or minus 0.381, 24.81 and 24.94 plus or minus 0.265, and 9.33 and 9.37 plus or minus 0.191, respectively. There was no effect (P = .416) of PEMF treatment on ultimate pH of striploins. Mean pH was 5.55 and 5.53 plus or minus 0. 016 for the treatment and control striploins, respectively. No PEMF treatment postmortem aging day interaction (P = .347) was observed for WBSF, and PEMF treatment did not influence (P = .328) WBSF. Mean shear force values were 3.13 kg and 3.22 kg plus or minus 0. 079 kg for treatment and control steaks, respectively. However, WBSF was influenced (P < .001) by aging day. Steaks aged 1 d were the least (P < .001) tender (3.88 kg) followed by 3 d (3.24 kg), which were less tender (P < .001) than steaks aged for 7 d (2.81 kg) or 14 d (2.78 kg). However, steaks aged 7 d did not differ (P = .855) from steaks aged for 14 d. No treatment postmortem aging day interaction (P = .761) was observed for percentage cook loss. Furthermore, PEMF treatment and aging day did not influence (P > .05) percentage cook loss of striploin steaks. Mean cook loss was 19.78% and 19.88% plus or minus 0. 496% for PEMF treated and control steaks, respectively.

Conclusion: The application of PEMF therapy to carcasses early postmortem did not influence lean color, ultimate pH, objective tenderness, or percent cook loss of beef striploins. While this technology has been proven effective at increasing muscle metabolism in living animals, the level of PEMF therapy applied to carcasses in this study did not elicit changes in muscle metabolism to an extent great enough to impact beef quality characteristics. Further research to evaluate alternative frequency, voltage, and/or application time is necessary to determine the efficacy of this technology to increase postmortem muscle metabolism in beef carcasses. Additionally, due to the proven efficacy of PEMF therapy on living animal muscle metabolism, further research to examine antemortem application and its impact on subsequent postmortem metabolism and meat quality could reveal alternative uses for this technology.

Funding Source: Iowa Beef Industry Council.

Keywords: beef, tenderness, pulsed electromagnetic field.

28 Evaluation of Pulsed Electromagnetic Field Therapy for Improving the Color Stability and Water-Holding Capacity of Beef Products

Haley R. Mouser^*, Sydni E. Lammers, Kylie N. Krueger, Judson K. Grubbs, Keith R. Underwood, Christina E. Bakker, and Amanda D. Blair, South Dakota State University, Brookings, SD 57007, USA *haley.mouser@sdstate.edu

Introduction/Objectives: Consumers have high expectations for fresh meat color because they associate color with freshness and quality product. A key aspect of improving shelf life of fresh beef products is improving color stability, which is associated with improved water-holding capacity. A potential method for improving water-holding capacity of meat is pulsed electromagnetic field (PEMF) therapy. This technology increases the rate of muscle metabolism and accelerates the rate of tissue repair when applied to live animals. Since muscles are metabolically active early postmortem, there is potential for the application of PEMF therapy to influence mechanisms regulating water-holding capacity and color stability of meat. Therefore, the objective of this study was to determine the influence of PEMF therapy on water-holding capacity and color stability (retail display) of beef striploin and eye of round steaks.

Materials and Methods: Beef cattle (n = 20) harvested in a northeast Iowa plant were selected based on a common hot-carcass weight (406 kg ± 5.8 kg) and quality grade (US Department of Agriculture, Choice). After carcass splitting, prior to cooler entry, PEMF treatment (PEMF Complete©) was applied to the loin and round on the right side of each carcass at 60 Hz and 230 V for 5 min. The left side did not receive PEMF treatment and served as the control. At 24 h postmortem, the striploin (m. Longissimus lumborum) and the eye of round (m. semitendinosus) from both sides of each carcass were collected and transported to the South Dakota State University Meat Laboratory. Subprimals were weighed in and out of the package and percentage purge loss was calculated. Subprimals were fabricated into 2.54-cm steaks. Four steaks from the striploins were aged for 1 d, 3 d, 7 d, or 14 d then frozen for determination of cook loss. One steak was assigned to assess color stability of a fresh sample. Strip steaks assigned to cook loss analysis were thawed at 4°C for 24 h, cooked on a flat-top grill to an internal temperature of 40°C, then flipped and continued cooking until reaching a final endpoint temperature of 71°C. Steaks were weighed before and after cooking to determine percent cook loss. Strip steaks and eye of round steaks assigned for color stability at 3 d postmortem were individually placed on Styrofoam trays, overwrapped with oxygen-permeable polyvinylchloride film, and placed under a stimulated retail display for 11 d. Instrumental color (L*, a*, b*) was recorded at 2 locations on each steak for the 11-d period. Data were analyzed using the MIXED procedure of SAS (SAS Institute, Cary, NC). Purge loss was analyzed as a randomized complete block design with carcass as the block and treatment as a fixed effect. Cook loss and instrumental color data were analyzed as repeated measures with day, treatment, and their interaction as fixed effects. Internal peak cooking temperature of each steak was used as a covariate for cook loss analysis.

Results: Application of PEMF treatment did not influence (P > .05) purge loss of striploins or eye of round subprimals. Purge loss of striploins were 0.72% and 0.83% plus or minus 0.094% and eye of rounds were 0.16% and 0.07% plus or minus 0.062% for the treated and control sides, respectively. No treatment aging day interaction (P = .761) was observed for cook loss. Furthermore, there was no effect (P > .05) of PEMF treatment or aging day on cook loss of striploin steaks. Mean cook loss was 19.78% and 19.88% plus or minus 0. 496% for PEMF treated and control steaks, respectively. No PEMF treatment day of retail display interaction was observed for instrumental color of striploin or eye of round steaks (P = .972 and P = .997, for loins and eye of rounds, respectively). However, PEMF treatment influenced lightness values with the PEMF treated striploin steaks having lower (P < .001) L* values than control steaks (45.60 vs. 46.17 ± 0.320, respectively). Conversely, in the eye of round, PEMF treatment resulted in increased (P = .035) L* values compared to control steaks (47.93 vs 47.70 ± 0.288, respectively). There was a tendency (P = .074) for PEMF treated striploin steaks to have increased redness (a*) values (19.16 vs. 18.84 ± 0.438, respectively) compared to control steaks. Application of PEMF did not influence a* values of eye of round steaks (P = .429) or b* values of the striploin steaks (P = .380). However, PEMF treated eye of round steaks had increased (P = .050) b* values compared to the control steaks (9.78 vs. 9.67 ± 0.180, respectively). Day of retail display was significant for L*, a*, and b* values (P < .001) in all steaks. Values for L* increased over the duration of the display period, whereas a* and b* values decreased over time. These shifts in color values are indicators of discoloration, thus demonstrating an increase in discoloration throughout the progression of the retail display.

Conclusion: The application of PEMF to beef carcasses early postmortem did not influence water-holding capacity as evaluated by purge loss and cook loss measurements. Application of PEMF treatment did differentially impact color of striploin and eye of round steaks throughout the duration of a stimulated retail display with PEMF treatment, resulting in lighter striploins but darker eye of round steaks as well as a tendency for increased redness values in striploins. However, while these color values were statistically different, further research is warranted to determine if consumers would be sensitive to these differences. Because PEMF has been proven effective in increasing antemortem muscle metabolism, further research could also examine antemortem application of PEMF therapy and its impact on subsequent meat quality and color stability. Additionally, further research should be conducted regarding the frequency, voltage, and time needed to optimize color outcomes.

Funding Source: Iowa Beef Industry Council.

Keywords: beef, color, pulsed electromagnetic field.

29 Impact of Solubilized Myofibrillar Beef Protein as a Meat Block Component for Processing and Quality Attributes in Fully Cooked Beef Meatballs

Michael Cropp, Michael Stender, Kayle Eivins^*, and Kristen Robbins, Kemin Industries, Des Moines, IA 50309, USA *kayle.eivins@kemin.com

Introduction/Objectives: The regulatory standard for a meatball (containing uncooked or cooked pork, beef, veal, or lamb) is that it must contain at least 65% of meat ingredients. Considering this standard of identity, utilizing solubilized myofibrillar beef protein (SMBP) as a component of the 65% meat block portion was investigated to determine the impact on the processing, shelf life, and quality attributes in fully cooked all-beef meatballs.

Materials and Methods: Four meatball formulations were manufactured (Fig. 1): a conventional beef meat block (1 control), in addition to beef meat blocks containing various meat block replacement (MBR) levels utilizing SMBP (Proteus^® B010) as a component of the total 65% meat block; 4% MBR (2); 8% MBR (3); and 12% MBR (4), respectively. All formulations included the same amount (35%) of nonmeat ingredients: water, salt, seasoned breadcrumbs, corn syrup, textured vegetable protein (TVP^®), soy protein concentrate, and a rosemary extract. The formulations were mixed, portioned into approximately 1.5-oz balls, thermally processed to 70°C, frozen to less than 0°C, packaged, and stored frozen (aerobically) at −8°C during 328-d shelf-life evaluation. Properties evaluated included cooked and chilled yield, proximate analysis, lipid oxidation (thiobarbituric acid reactive substances [TBARS]), and sensory properties including flavor, texture, juiciness, and overall acceptability. The study was replicated twice, with replications produced on consecutive days. Statistical analysis of formulation and day (main effects) and 2-way interactions using STATGRAPHICS Centurion 18 software with significance determined at a P value of less than .05. Trending P values were determined at a P value greater than or equal to .05 and less than .10.

Results: Cooked proximate composition for fat, protein, and moisture were not significantly different for any formulation. There were no significant processing differences in cook yield or chilling/freezing loss. The overall process yield and yield to green impact of SMBP inclusion is displayed in Figure 1. Results for lipid oxidation by TBARS analysis indicate no significant formulation difference but a significant storage time effect where day 90 was lower than day 180. However, TBARS generally exhibited very similar values throughout 328 d of storage. Sensory results for flavor intensity showed no formulation differences but revealed a significant day effect for less intense flavor during storage time across all formulations. Sensory results for texture showed a trend (P = .083) for softening during storage time. Sensory juiciness and mean overall acceptability showed no differences.

Conclusion: The present study’s findings highlight that product composition is unchanged with MBR using SMBP. Process yield was not impacted and showed numerical mean improvements across all MBR levels tested compared to the control formulation. Additionally, substantial improvements were observed when factoring in yield back to the initial meat block (yield to green). Sensory attributes and lipid oxidation showed no meaningful formulation differences. The findings demonstrate that SMBP can be included as a meat block component without adversely affecting product performance or quality attributes during shelf life.

Figure 1.

Composition of meatball formulations containing nonmeat ingredients, beef trim with solubilized myofibrillar beef protein as a meat block replacement of beef 90s, and yield^1,2 attributes. ¹Yield to green (%): cooked and chilled weight/initial raw beef 50 and 90 trim weight (P = .562). ²Process yield %): cooked and chilled weight/raw formulation weight (P = .763). MBR, meat block replacement; SMBP, solubilized myofibrillar beef protein.

Funding Source: Kemin Food Technologies.

Keywords: meatballs, processed meat, sensory yield.

30 Application of High-Pressure Processing Alters the Color of Cow Tenderloins

Kara A. Reynolds^1,*, Leila G. Venzor¹, Ashley A. Hahn¹, Grace C. Johnson¹, Jordan C. Wicks¹, Mary-Grace C. Danao¹, Ranjith Ramanathan², and Gary A. Sullivan¹, ¹University of Nebraska–Lincoln, Lincoln, NE 68588, USA, ²Oklahoma State University, Stillwater, OK 74078, USA *kreynolds15@huskers.unl.edu

Introduction/Objectives: Cull cows represent 10% of the US beef industry; however, the inherent characteristics of the meat make it less marketable than that of beef from young, finished cattle. The dark lean color and tenderness concerns of cow meat limit consumer acceptance. Even so, the psoas major (PM) muscle is still remarkably tender, arguing that if color of cow tenderloins (PM) could be improved, value could be added back to cow carcasses. Recent works have shown that high-pressure processing (HPP) can lighten and improve redness of lean in conventional high pH dark-cutting beef. While the mechanism in which this happens has yet to be determined, color changes occur in the absence of pH change, suggesting dark lean, regardless of pH, can be improved. Therefore, the objective of this experiment was to evaluate the effect HPP has on color, oxidative stability, and tenderness of PM muscle from cull cows.

Materials and Methods: Forty cull cow tenderloins were obtained from a commercial abattoir and transported on ice to the University of Nebraska–Lincoln (UNL) Loeffel Meat Laboratory. Vacuum-packaged tenderloins were held in dark refrigeration (2 ± 1°C) conditions for 72 h. Tenderloins were faced on the posterior end (6–7 cm), and a 27.9-cm portion sample was collected from each tenderloin. Tenderloin portions were vacuum packaged and assigned to 1 of 5 pressure (MPa) and holding time(s) treatments: 300MPa-60s, 300MPa-90s, 375MPa-60s, 375MPa-90s, and positive control (non-HPP, PC). Additionally, 8 US Department of Agriculture choice tenderloins, serving as negative control (non-HPP, NC), were procured from a commercial abattoir, and transported and processed under similar conditions as previously described. Tenderloins subjected to the assigned HPP treatment at the UNL Food Processing Center. Samples were stored in dark, refrigerated (2 ± 1°C) conditions for 24 h. Tenderloins were removed from packaging and divided into 6 portions (n = 1, 5-cm steak; n = 4, 3-cm steak; n = 1, 1-cm steak). Three, 3-cm steaks from each sample were placed on Styrofoam trays and overwrapped with polyvinyl chloride film. Samples were subjected to a 7-d simulated retail display. Subjective color was observed once daily by a trained panel using 3 established scales: paleness (1–6; 6 being very pale), discoloration (1–6; 1 having no discoloration), and color score (1–8; 1 being bleached red). Instrumental objective color (L*, a*, b*) was collected daily with a Minolta CR-400 colorimeter (Ramsey, NJ). Additionally, retail display steaks were collected on days 0, 3, and 7 and cryogenically frozen and stored (−80°C) for thiobarbituric acid reactive substances and pH analysis. One steak per sample was collected on day 0 for Warner-Bratzler shear force and stored at −20°C until the time of analysis. Data were analyzed using the GLIMMIX procedure of SAS 9.4 (SAS Institute, Cary, NC, USA). Main effects of HPP treatment (pressure and time) were evaluated within day in a completely randomized design factor. Significance was determined at α equal to 0.05.

Results: On all days during retail display, the 375MPa-90s treatment was lighter (P < .05) than all other treatments, except the 375MPa-60s. The 300MPa-60s had similar L* values to the NC on days 0, 1, 2, and 6, and 300MPa-90s were similar to the NC on day 0. The non-HPP-treated PC was among the darkest (lowest L* value) throughout (P < .05) but was similar to the NC on day 6 (P < .05). For a* values, the 375MPa-90s treatment was less red (P < .05) than the NC on all days except day 1. Compared to the PC, 375MPa-90s was redder on day 0, but the redness deteriorated over time with lower a* values on days 3 through 7 (P < .05). Both 375MPa treatments had among the greatest b* values and were similar to the fed-beef NC on days 1 through 7. The non-HPP PC control was among the lowest b* values (P < .05) but similar to 300MPa-60s on days 1 through 7. In color panel evaluations, the PC always had the highest color score (darkest color), followed by the NC. As HPP pressure and holding time within pressure increased, color scores declined. Similarly, the PC had the lowest paleness scores (least pale), followed by the NC. In general, as pressure and holding time increased within pressure, the paleness scores increased. The 375MPa-90s were among the most discolored, beginning on day 2. The PC was similar to 300MPa-60s on all days except 0 and 5 and 300MPa-90 on all days except day 5 (P > .05). There were no differences in lipid oxidation on day 0 of the retail display (P < .0001). On day 3, pressure-treated steaks showed significantly increased oxidation compared to NC and PC treatments (P < .001). On day 7, both 375MPa and 300MPa-60s exhibited the highest lipid oxidation, while NC and PC had the least (P < .0001). Tenderloin pH differed on day 0 with NC being significantly higher than all other treatments except 375MPa-60s; however, there was no difference among HPP-treated tenderloins (P = .0177). Across all treatments, no differences for pH were identified on days 3 and 7 (P = .4893, P = .1826, respectively). Additionally, all cow tenderloin treatments had significantly greater shear force values than the NC (P = .0007).

Conclusion: Subjecting cull cow tenderloins to HPP increased initial lightness, with the 375MPa-90s treatment being the most effected. Initial improvements in redness deteriorated over time and were more pronounced at the higher pressures. HPP-treated cow tenderloins were lighter, but visual discoloration increased over time, particularly in higher pressure treatments such as 375MPa-60s and 375MPa-90s. Shear force was similar among HPP-treated and untreated cull cow samples (PC) but remained tougher than NC tenderloins. While HPP may enhance initial color, the product quality deterioration was more rapid, especially at higher pressures and longer holding times. Investigating lower HPP pressures and shorter holding times may be warranted to optimize the initial color benefits of HPP and maintain shelf-life color stability.

Funding Source: This project was funded in part by the Beef Checkoff and the Nebraska Beef Council.

Keywords: high-pressure processing, cull cows, color cow tenders, shelf life.

31 Release of Antioxidants From Biodegradable Polylactic Acid Meat Packaging Films

Noah Jewell^1,*, Anibal Bher², Rafael Auras², Prabir Ghari¹, Gretchen Mafi¹, Morgan Pfieffer¹, and Ranjith Ramanathan¹, ¹Department of Animal and Food Sciences, Oklahoma State University, Stillwater, OK 74078, USA, ²School of Packaging, Michigan State University, East Lansing, MI 48824, USA *noah.jewell@okstate.edu

Introduction/Objectives: Plastic pollution has led to an increased demand for more sustainable packaging materials among consumers. Biodegradable polymer films, such as polylactic acid (PLA), have the potential to replace petroleum-based polymers, including polyvinyl chloride. However, biodegradable films have poor barrier characteristics, leading to increased oxygen transmission and an increased rate of discoloration and oxidation in meat products. The inclusion of antioxidants in the film mix is a viable method to reduce the oxidative impact of PLA films. However, a major limitation is its inability to withstand high temperatures during the film extrusion process. Encapsulation of antioxidants within cyclodextrins, a type of glucose capsule, can enhance the thermal stability of antioxidants, making the encapsulated antioxidants potentially suitable for incorporation throughout the processing of PLA films. Therefore, the objective of this study was to incorporate cyclodextrin-embedded antioxidants within PLA films and determine their ability to release antioxidants.

Materials and Methods: Commercially purchased cyclodextrin powders consisting of citral, coenzyme Q10, and curcumin were obtained from a commercial producer. 1.5 kg of Ingeo^™ biopolymer 2003D poly (96% l-lactic acid) (PLA) resin from NatureWorks LLC (Minnetonka, MN) were mixed with 300 g of cyclodextrin powder to achieve an approximate inclusion of 10%. The mixture was then dried in a 50°C oven to remove any ambient moisture. Polymer-treated batches were processed utilizing a twin-screw extruder before palletization to formulate a master batch for further processing. Masterbatches were dried at 50°C before processing in a Randcastle single-screw extruder under uniform temperature, screw rpm, and roller rpm to create monolayer cast films. A similar approach was used to prepare control PLA film, citral, coenzyme Q10, and curcumin. Curcumin and coenzyme Q10 films had a slight yellowish tinge in the film, while citral films did not impart any color. The antioxidant release from the film was tested using 3 different solvents: 100% water, 100% methanol, and 50% water-50% methanol mixture. Approximately 3.8-cm² films were cut from the control, citral, coenzyme Q10, and curcumin. The films were immersed in 3 different solvents separately for 24 h. The antioxidant levels in 3 solvents were tested using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. The experiment was replicated 7 times. The data were analyzed using the MIXED procedure of SAS, and significance was considered at a P value of less than .05.

Results: A significant interaction between solvent type and antioxidant (P < .05) resulted in the release of antioxidant from the biodegradable film. A significant interaction observed for both DPPH and ABTS assay. Out of the 3 antioxidants, curcumin showed the greatest antioxidant activity. Curcumin release was more in methanol, followed by a mixture of water and methanol, and water alone when antioxidant activity was measured using DPPH (methanol > mixture > water; P < .05). ABTS assay also indicated curcumin in ethanol resulted in greater release than citral or coenzyme Q10. For example, the ABTS assay indicated curcumin in ethanol led to 73.6% radical scavenging ability, while water as a solvent resulted in 10% radical scavenging ability. Interestingly, there was little difference in antioxidant activity between citral and coenzyme Q10. For both citral and coenzyme Q10, water as a solvent resulted in a better release of antioxidants (only numerical greater DPPH assay results; P > .05) than ethanol or mixture.

Conclusion: The results suggest that cyclodextrin-encapsulated curcumin was able to withstand greater temperatures and resulted in greater antioxidant activity than cyclodextrin-encapsulated citral or coenzyme Q10 films. The antioxidant release was 7-fold greater in ethanol than in a methanol-water mixture or water as a solvent. Release of antioxidants is an important consideration when using them in meat packaging to minimize quality changes with storage time.

Funding Source: This research was in part funded by Ramanathan’s Endowed Chair Funds.

Keywords: polylactic acid, biodegradable, cyclodextrin, encapsulation.

32 Impact of Phosphates as an Enhancement on the Yield and Quality of Marinated Chicken Breasts or Marinated and Breaded Chicken Fritters

Bryant Sawin¹, Ambri Harrigal^1,*, Olivia Ron², Trent Schwartz¹, Loni Lucherk¹, and Ty Lawrence¹, ¹Department of Agricultural Sciences, West Texas A&M University, Canyon, TX 79016, USA, ²ICL Group, St. Louis, MO 63141, USA *aharrigal@wtamu.edu

Introduction/Objectives: Phosphates improve yield and quality of meats via changes in pH. An increase in pH allows for increased moisture retention and an improvement in shelf life. Phosphates are chelators of cations, which reduce the ability of free radical formation in a product and the subsequent formation of rancid flavors. The objective of this study was to quantify the effects of phosphate treatments upon production yield and quality outcomes when utilized in marinated or marinated and breaded chicken fritters.

Materials and Methods: Chicken breasts were vacuum tumbled for 30 min in 1 of 4 phosphate (0.48% inclusion) treatments ([1] no phosphate control; [2] sodium tripolyphosphate [STPP] with a pH range of 9.5–10.1; [3] Brifisol 512, a blend of 2 phosphates with a pH range of 8.7–9.3; or [4] Brifisol 960, a blend of 2 phosphates and pH range of 9.5–10.1). Salt was included at 0.75% for phosphate inclusion treatments and 1.23% for control. All samples rested for 5 min after tumbling and were then vacuum packaged and frozen (−23.3°C). Breaded chicken fritters were similarly produced, utilizing no phosphate control, STPP, Brifisol 450, a blend of 3 phosphates with a pH range of 7.2 to 7.8, and Brifisol 960 at 0.48% inclusion. Batter was mechanically added to each chicken breast, prior to being par fried, cooked to an internal of 71.1°C before cooling, and then vacuum packaged and frozen (−23.3°C). After 30 d of frozen storage (−23.3°C), marinated samples were thawed and evaluated for purge loss, cooking loss, thiobarbituric acid reactive substances (TBARS) of raw and cooked samples, and aerobic plate count (APC) of raw samples after 1 d, 5 d, 9 d, and 13 d of refrigerated storage (3.3°C). Trained sensory panelists evaluated marinated chicken breasts for overall flavor, saltiness, bitterness, metallic flavor, particle size, tooth pack, tenderness, juiciness, and hardness. Breaded chicken fritters were analyzed for brine uptake, batter pickup, and cook loss. Breaded chicken fritters were also cooked from frozen in a deep fryer and evaluated by a trained sensory panel for overall flavor, saltiness, juiciness, tenderness, hardness, and crunchiness. Mixed models were used for analysis. Phosphate treatment and time in refrigerated storage were fixed effects. Single degrees of freedom contrasts tested Brifisol versus STPP, phosphate treatments versus control, and linear and quadratic time effects.

Results: No difference in brine pickup of marinated chicken breasts was detected between treatments (P = .812). An interaction (P < .001) occurred for purge loss, in which control samples had increasingly greater purge losses over time compared to phosphate treatments that all tended to follow a similar decreasing pattern over time, with a slight increase on the last day. Phosphate treatments had less purge losses (P = .001) than control. Brifisol 960 had lower purge losses than Brifisol 512, whereas STPP was similar and intermediate to both phosphate blends. Purge losses increased (P = .004) over time after thawing in a quadratic manner. Cooking losses did not differ between phosphate treatments (P = .112) or due to time (P = .811) after thawing. Samples differed (P = .008) in APC between treatments. STPP (5.06 Log CFU/g) tended to differ (P = .065) from Brifisol 960 (4.68 Log CFU/g) but was higher (P < .004) than Brifisol 512 (4.43 Log CFU/g) and control (4.43 Log CFU/g) samples. APC values increased (P < .001) over time after thawing in a quadratic manner. Control (1.79 mg/1000 g) samples had higher (P = .005) cooked sample TBARS values than Brifisol 960 (0.62 mg/1000 g) and Brifisol 512 (0.51 mg/1000 g) but were not different from STPP (1.10 mg/1000 g) samples. No difference (P = .190) was detected between treatments in uncooked sample TBARS values. No difference (P = .200) was detected between treatments for overall chicken flavor. Control samples were reported by trained panelists to be saltier (P = .002) than all other treatments. No difference (P ≥ .115) was detected between samples for bitter or metallic off flavors, particle size, tooth pack, tenderness, juiciness, or hardness. For breaded chicken fritters, differences between phosphate treatments were not detected for percentage brine uptake (P = .113), percentage batter pickup (P = .194), or cooking losses (P = .229). No differences (P ≥ .407) were detected for overall chicken flavor, saltiness, juiciness, or hardness. Control samples were rated crunchier (P < .001) than those that included STPP or Brifisol 960, whereas samples that included Brifisol 450 were intermediate.

Conclusion: In marinated chicken breasts, phosphate samples had consistently lower purge loss over time compared to control. No difference was detected between cook loss of all treatments. Brifisol 512 and 960 had lower cooked TBARS than control but were not different than STPP. The addition of phosphates did not alter sensory flavors of marinated chicken breasts. With the exception of crunchiness, no differences were detected in breaded chicken fritters.

Funding Source: Research funded by ICL Group of St. Louis.

Keywords: food safety, palatability, poultry, processing.

33 Impact of Ultraviolet-A Spectrum Dehydration on the Shelf Stability of Beef Jerky

Mohammed A. Alruzzi^*, Fatema R. Mishu, Madeleine R. Monsivais, Luis J. Bastarrachea, and Sulaiman K. Matarneh, Department of Nutrition, Dietetics and Food Sciences, Utah State University, Logan, UT 84322, USA *mohammed.alruzzi@usu.edu

Introduction/Objectives: Drying is a widely used preservation method to inhibit microbial growth and deterioration reactions, effectively extending the shelf life of foods. Various drying techniques are available, including hot-air drying, freeze drying, microwave drying, osmotic drying, and ultraviolet (UV) light drying, each with advantages and limitations. UV light in the A spectrum (UV-A) is an effective nonthermal drying method that remains largely unexplored in the meat industry. Jerky is a cured and dried meat product typically made from lean beef cuts and dehydrated in a smokehouse to achieve a water activity (a_w) of 0.85 or lower. This study aimed to compare the physicochemical properties of jerky dehydrated with UV-A light to that dehydrated in a conventional convection oven over an extended storage period.

Materials and Methods: Six beef top rounds of similar weight and quality grade were obtained from a local beef processing facility. From each top round, 80 uniform beef strips (3.5 × 1.25 × 0.2 in) were obtained and weighed. Strips were treated with sodium nitrite (40 mg/kg), erythorbate (550 mg/kg), and salt (15 g/kg), then incubated overnight at 4°C. The following day, 40 strips from each top round were randomly selected, individually weighed, and dehydrated in a thermal oven at 93.3°C for 55 min, while the remaining 40 strips were dehydrated in a UV-A light chamber for 255 min. The yield after dehydration was calculated by reweighing the strips and expressing the final weight as a percentage of the initial weight. Drying durations were selected to yield similar final moisture contents across treatments. The jerky produced from each dehydration method was divided into 5 equal portions, with each portion individually vacuum packaged. One package from each dehydration method was used immediately (no storage; 0 d), while the remaining packages were stored at room temperature, with constant illumination of 12 h/d for 30 d, 60 d, 120 d, or 180 d. The packages were opened at the end of each storage period, and the jerky was tested for moisture content, a_w, Warner-Bratzler shear force (WBSF), color, and lipid oxidation. Obtained data were analyzed with a mixed model for repeated measures in JMP (SAS Institute Inc., Cary, NC). The statistical model included the fixed effects of treatment, storage duration, and their interaction and the random effect of the top round.

Results: Both moisture content and a_w decreased over time in both drying methods (P < .0001). However, no differences in moisture and a_w were detected between treatments at any time point. WBSF values were greater in UV-A light-dried jerky than their oven-dried counterparts at 120 d (P = .01), while no differences were observed at any other time point. Jerky dehydrated with UV-A light had lesser lightness (L*) and yellowness (b*) values at all time points compared to those dehydrated in the oven (P ≤ .03). Redness (a*) differed between the 2 drying methods at only 180 d, with lesser a* values for the UV-A light-dried jerky than the oven-dried samples (P < .001). Lipid oxidation was evaluated with thiobarbituric acid reactive substances (TBARS), with an increase in TBARS observed in both treatments as storage time progressed (P < .0001). UV-A light-treated samples exhibited greater TBARS values at 120 d and 180 d compared to the control samples (P ≤ .03).

Conclusion: Our results demonstrate that UV-A light drying produces jerky with comparable moisture content, a_w, and WBSF compared to oven drying over a 180-d storage period. Color analysis revealed lower color intensity in the UV-A light-dehydrated samples, an effect maintained throughout the entire storage period. Although UV-A samples exhibited greater lipid oxidation at 120 d and 180 d, values remained below the threshold of sensory-detectable rancidity. These findings highlight the potential of UV-A light as a viable alternative to conventional thermal drying methods. However, due to its nonthermal nature, UV-A light dehydration alters some jerky characteristics, necessitating sensory analysis to evaluate consumer acceptance.

Funding Source: Utah Agricultural Experiment Station.

Keywords: beef jerky, drying, lipid oxidation, ultraviolet, shelf stability.

34 Effects of Sous-Vide Cookery on Tenderness, Degrees of Doneness, and Cook Loss Compared to Clamshell Cookery

D. Hamilton Thomas^*, Clint T. Lee, Muhammad Junaid Nawaz, J. Anna Scott, and Alexander M. Stelzleni, University of Georgia, Athens, GA 30602, USA *hamp@uga.edu

Introduction/Objectives: Traditional clamshell (CS) cooking methods have variation in cooking time, degrees of doneness (DOD), and max temperature. Sous vide (SV) is a form of cooking utilizing a controlled circulating water bath to cook sealed vacuum-packaged products. This method has grown in popularity in research methodology and for consumers and the restaurant industry for its consistent results and temperature control. While some research has been done, there is still more information to be gained on the impact of SV and holding times. Information gained from such research will aid in restaurant and home chef efficacy, optimizing the benefits of SV techniques. The objective of this study was to evaluate the effects of cooking method (CM) with extended SV times and location (LOC) within the last one-third section of the longissimus lumborum (LL) on texture attributes and cooking losses.

Materials and Methods: Twenty frozen posterior one-third sections of LL were selected from a prior finishing study (aged 14 d). Four frozen steaks (2.5-cm thick) were cut out of each section using a guiding edge on bandsaw. Steaks were labeled by LOC (1–4), anterior to posterior, and any presence of vein steak or Gluteus medius was noted. The steaks were vacuum packaged with respective labels and placed back in the freezer (−25 ± 2°C) before any thawing could occur. Steaks were blocked by LOC and assigned to 1 of 4 cooking treatments: CS (CM), SV without holding time (SV0), SV plus 30 min holding time (SV30), and SV plus 60 min holding time (SV60). All steaks were cooked to target a final cooking temperature of 57.2°C. Frozen weight, total loin eye area (including fat), LL area only, and 4-point thickness were measured before steaks were thawed in a cooler (2 ± 2°C; 24 ± 2 h). The steaks in CS were cooked and removed from the heat source at 55°C to compensate for residual heat transfer through the steak. The SV treatments had the water bath set at 57.2°C, SV0 steaks were removed upon reaching the 57.2°C, SV30 steaks were removed 30 min after reaching 57.2°C, and SV60 steaks were removed 60 min after reaching 57.2°C. All steaks were monitored after cooking to ensure the maximum temperature was recorded. After cooking, samples were placed in the cooler (2 ± 2°C) for 22 h plus or minus 2 h on trays wrapped with cling film. Six cores (1.27-cm diameter) were removed parallel to the muscle fibers. Sample cores were sheared perpendicular to the muscle fibers using a v-slot blade after equilibrating to room temperature. The peak force (kg) of the 6 cores from each steak was averaged for Warner-Bratzler shear force (WBSF). Data were analyzed as a randomized complete block design with 4 × 4 factorial arrangement using the Proc-MIXED procedure of SAS 9.4. Fixed effects included CM and LOC, and the random term was cooking day. Means were separated using the PDIFF option of LSMEANS with at α less than or equal to 0.05.

Results: All steaks had a marbling score of 545 plus or minus 120. There were no CM × LOC interactions for total loin eye area, LL area, thaw loss, cooking time, cooking loss, WBSF, or DOD (P > .05). As expected, as LOC progressed from anterior to posterior, LL area was reduced (P < .01) but did not influence cook time. Steak LOC affected (P < .03) thaw loss, where LOC1 had greater (P < .03) thaw loss than LOC2, LOC3, and LOC4, while LOC2, LOC3, and LOC4 were not different from each other (P > .05). The CS had 8.62% and 7.1 % greater cook loss from SV0 and SV30, respectively (P < .02), and was not different (P > .05) from SV60. SV60 had 7.05% greater (P < .02) cook loss than SV0 and was not different (P > .05) from SV30. Steak LOC did not affect (P > .05) cook loss. WBSF was not different among SV0, SV30, and SV60 (P > .05); however, CS had greater (P < .05) WBSF than any of the SV treatments. There was no LOC effect on WBSF (P > .05). CM impacted DOD (P < .01). CS had greater DOD than SV0, SV30, and SV60 (P < .01), whereas there was no difference found in DOD among all 3 SV treatments. DOD were not affected (P > .05) by LOC.

Conclusion: SV cookery of LL steaks will decrease cooking loss, result in a more consistent DOD, and provide a more tender product. Steaks cooked SV to 57.2°C can also be held in SV for up to 60 min without influencing objective tenderness but may impact cook yields.

Funding Source: US Department of Agriculture—Hatch.

Keywords: sous vide, tenderness, yield.

35 Untapped Potential: How Clean Label, Native Pea Starch Can Improve Yield and Texture of Emulsified Meat

James Chapa^* and Aubrey Hunsaker, Ingredion, Englewood, CO 80112, USA *james.chapa@ingredion.com

Introduction/Objectives: Starch is widely used in diverse meat products to improve water holding, yield, purge, and freeze-thaw stability. Corn and potato-based starches are commonly used, with the latter usually improving textural firmness and cook yield due respectively to its higher amylose content and lower gelatinization temperature, whereby the starch binds water as meat proteins denature and starts losing water. Pea starch is available as a coproduct of pea protein isolate manufacture but is currently underutilized in the United States compared to Europe. Pea starch may perform well in meat applications due to its low gelatinization temperature and elevated amylose content but has also been expected to result in higher purge compared to other starches. The objectives of this work included evaluation of the performance of pea starch in a typical emulsified meat application compared to sodium tripolyphosphate (STPP) and corn starch and determination of the impacts of different pea starch use levels.

Materials and Methods: Pea starch was evaluated in frankfurters made with mechanically separated chicken at 1%, 2.25%, and 3.5% starch use levels compared to a negative control, a phosphate control (made with 0.50% STPP), and a native corn starch control (made with 2.25% corn starch) (see Table 1). Frankfurter batters were prepared by thawing frozen mechanically separated chicken and chopping with other formula ingredients to a final temperature of 55°F to 60°F; vacuumized; stuffed into 26-mm diameter cellulose casings; thermally processed in an Enviro-Pak smokehouse with schedule comprising drying (30 min at 130°F with 40% relative humidity), smoking (60 min at 145°F with 40% relative humidity and pecan hardwood smoke), and steam cooking (at 170°F to internal temperature of 160°F); cold water showered; pealed; vacuum packaged; and stored refrigerated (34°F) for further analysis. Two processing replications were prepared for each treatment. Cook yield was determined by weighing 6 links of each treatment before and after smoking and cooling. Purge, color, pH, and texture were analyzed every week for 4 wk of refrigerated storage (34°F). Purge was evaluated as the weight of liquid remaining in each package as a percentage of the total weight. L*a*b* color was evaluated using a Konica Minolta CM-600d spectrophotometer. pH was evaluated with a calibrated Thermo-Scientific flat surface pH electrode. Texture was analyzed instrumentally with a texture analyzer performing texture profile analysis (TPA) to 60% strain on sections of each frankfurter cut to 30-mm height and brought to room temperature (a minimum of 18 sections were measured per treatment). Statistical analysis comprising analysis of variance and Tukey post-hoc analysis were performed in Minitab^® version 22.2.1. Samples of 2 different brands of frankfurters made with mechanically separated chicken were also purchased from the market and analyzed with the same methods for benchmarking purposes.

Results: Cook yields exhibited a narrow range from 86.4% plus or minus 0.14% to 87.9% plus or minus 0.54%. As shown in Table 2, within this range, the 3.5% pea starch and 2.25% corn starch treatments resulted in the highest cook yields. One percent and 2.25% pea starch treatments neither increased nor negatively impacted yield compared to the negative and phosphate controls. In-package purge results from were not statistically different (P = .697), ranging from 1.30% to 1.93% plus or minus 0.39%, within the range of the 2 evaluated market benchmark samples (1.18–2.62%). All treatments narrowly ranged in pH from pH 6.44 to 6.51 plus or minus 0.03, which is more similar to the mean pH of 1 of the 2 evaluated market benchmark samples than the other (6.43 ± 0.02 vs. pH 6.16 ± 0.01). The phosphate control exhibited an expected slightly raised pH, whereas the starch treatments had little impact on pH compared to the negative control. All treatments exhibited similar L*a*b* color to market benchmark samples (L*: 56.1–60.3, a*: 13.7–20.2, b*: 14.1–22.7). No starch treatment significantly increased the L* value as might be expected due to their bright white color. As shown in Table 3, the TPA results were in a similar range as the 2 market benchmark samples, which did exhibit significant textural differences from each other. Resilience, cohesiveness, and chewiness were strongly impacted if the first TPA compression resulted in total fracture of the sample, which did occur for all tested samples of the market benchmark frank #1 but not market benchmark frank #2. Two point twenty-five percent and 3.5% pea starch resulted in the highest hardness, springiness, cohesiveness, and chewiness of the starch treatments (only the hardness of 2.25% pea starch was statistically higher than controls and corn starch). One percent pea starch underperformed on hardness, chewiness, and resilience but still statistically increased these parameters compared to the phosphate and negative controls. Overall, although there were statistical differences, the magnitude of differences between treatments in this study was not robust, suggesting that more significant process changes, such as switching casing type and/or altering the smoke schedule, and/or formula changes, such as varying the mechanically separated chicken content, testing with additional animal protein sources (e.g., pork, beef, or blends), or evaluating special conditions such as low fat, low sodium, or high extension conditions will be required for a comprehensive understanding of the functional utility of pea starch in emulsified meat products.

Conclusion: While the optimal use level of pea starch in different meat products will depend on specific formulas and processes, in this study 2.25% and 3.5% pea starch resulted in comparable instrumental textures, whereas only 3.5% pea starch increased cook yield, and no starch treatment increased in-package purge. Although further research is needed, this study suggests that pea starch has potential to be used similarly to other native starches in emulsified meat applications, where it can assist with water holding and help enable common industry objectives such as yield improvement, phosphate replacement (for clean label products), texture modulation, and cost reduction. Next steps include larger scale processing, sensory evaluations, and testing pea starch in a broader range of products, such as sliceable deli meats.

Funding Source: Ingredion.

Keywords: starch, emulsified, frankfurter, phosphate, pea.

36 Defining the Parameters of High-Pressure Processing to Improve the Visual Appearance of Dark-Cutting Beef

Ashley A. Hahn^1,*, Leila G. Venzor¹, Shelley A. Curry¹, Grace C. Johnson¹, Mary-Grace Danao², Ranjith Ramanathan³, Jordan C. Wicks¹, and Gary A. Sullivan¹, ¹Department of Animal Science, University of Nebraska–Lincoln, Lincoln, NE 68588, USA, ²Department of Food Science and Technology, University of Nebraska–Lincoln, Lincoln, NE 68588, USA, ³Department of Food and Animal Sciences, Oklahoma State University, Stillwater, OK 74078, USA *ahahn17@huskers.unl.edu

Introduction/Objectives: Dark-cutting beef has been a persistent issue for the beef industry, highlighting the need for mitigation strategies. Previous research has observed the use of high-pressure processing (HPP) to increase the lightness and redness of dark-cutting beef; however, knowledge on the optimal combination of pressure and holding time is limited. Therefore, the objective of this study was to define the parameters to achieving an improved visual appearance in dark-cutting beef.

Materials and Methods: Twelve dark-cutting (mean pH = 6.6) striploins were obtained from a commercial beef processor. Five days after collection, striploins were cut into five 6.35-cm sections, randomly assigned an HPP treatment, and vacuum packaged for processing. Each striploin was randomly assigned a pressure of either 300 MPa or 450 MPa, then subsequent sections were assigned 1 of 5 holding times (in seconds): 0 (no HPP, control), 1 (HPP pressurization), 30, 60, and 90. After 48 h of dark storage post-HPP treatment, sections were cut into 3 steaks for objective and subjective color, pH, thiobarbituric acid reactive substances (TBARS), and Warner-Bratzler shear force (WBSF). Color measurements were obtained for days 0 through 7 of retail display, whereas pH and TBARS values were measured for days 0, 3, and 7 and WBSF for days 0 and 7. Data were analyzed with the GLIMMIX procedure of SAS 9.4 by pressure within day for the main effect of holding time using a randomized complete block design with loin considered a random effect.

Results: Prior to HPP application, there were no differences among samples assigned to different treatments for lightness (L*), redness (a*), and yellowness (b*). At 300 MPa, there was a holding time effect for L* (P ≤ .0362), except on days 1 (P = .1626) and 6 (P = .1598). The 90-s treatment had greater lightness than the HPP pressurization group for days 0, 2, 3, and 4 (P ≤ .0046) as well as the non-HPP control and the 30-s groups on day 5 (P = .0055). At the 450-MPa pressure, the steaks with 60-s and 90-s holding times were lighter than the non-HPP and HPP pressurization groups for all days (P < .0001). For redness, there was an effect due to HPP treatment for all days (P ≤ .0019) at both pressure levels. The 30-, 60-, and 90-s treatments were redder than the HPP pressurization group at the 300-MPa pressure and the non-HPP control at the 450-MPa pressure. Similarly, yellowness values were greater for the 60-s and 90-s groups compared to the HPP pressurization group at 300 MPa. Furthermore, the 30-, 60-, and 90-s groups had greater yellowness than the non-HPP control at the 450 MPa. For subjective color assessments, the 300-MPa pressure the 90-s treatment had lower color scores, indicating a lighter lean color than the non-HPP control, HPP pressurization, and 30-s groups for all days (P ≤ .001). At 450 MPa, the non-HPP control showed the greatest color score with the 30-, 60-, and 90-s treatments having among the lowest scores (P < .0001). There were minimal differences between holding times for surface discoloration at both pressures. For laboratory analyses, the 300-MPa group had differences between treatments for TBARS values on day 3, with the 90-s group having greater lipid oxidation than the non-HPP controls (P = .0109). For the 450-MPa pressure, the 30-, 60-, and 90-s times had greater lipid oxidation than the non-HPP control for all days and the HPP pressurization group on days 3 and 7 (P < .0001). There were no differences between treatments for pH at either pressure (P ≤ .1578). Also, differences in WBSF values were observed on day 7 at 450 MPa, where the 90-s group exhibited higher shear force values than the non-HPP control and HPP pressurization groups (P = .0032).

Conclusion: Results indicate that improved appearance can be seen at the 300-MPa pressure when held for 30 s or more by increasing lightness and redness values. Additionally, minimal effects on lipid oxidation and tenderness were observed at this pressure. At 450 MPa, lightness and redness were increased. However, treatment at this pressure with longer holding times may result in excessive lightening as well as increased lipid oxidation.

Funding Source: This project was funded in part by the National Beef Cattlemen’s Association.

Keywords: dark-cutting beef, high-pressure processing, holding time, color.

37 Utilizing High-Pressure Processing to Improve Dark-Cutting Beef Appearance in Psoas Major

Ashley A. Hahn^1,*, Leila G. Venzor¹, Shelley A. Curry¹, Grace C. Johnson¹, Mary-Grace Danao², Ranjith Ramanathan³, Gary A. Sullivan¹, and Jordan C. Wicks¹, ¹Department of Animal Science, University of Nebraska–Lincoln, Lincoln, NE 68588, USA, ²Department of Food Science and Technology, University of Nebraska–Lincoln, Lincoln, NE 68588, USA, ³Department of Food and Animal Sciences, Oklahoma State University, Stillwater, OK 74078, USA *ahahn17@huskers.unl.edu

Introduction/Objectives: High-pressure processing (HPP) has previously been explored as a mitigation strategy for improving the visual appearance of dark-cutting beef. However, previous studies have focused primarily on Longissimus lumborum, a color stable muscle, but limited knowledge is available on the effect of HPP on color labile muscles such as the Psoas major, commonly known as the tenderloin. Therefore, the objective of this study was to examine the effect of HPP on dark-cutting color labile muscle.

Materials and Methods: Six normal-pH (mean pH = 5.4) and 12 dark-cutting (mean pH = 5.8) tenderloins were collected from a commercial beef processor. Five days after collection, tenderloins were portioned into two 10.0-cm sections, randomly assigned an HPP treatment, and vacuum packed. Dark-cutting tenderloins were assigned a pressure (300 or 450 MPa), then subsequent sections were assigned a holding time of either 90 s or 0 s (no HPP, dark-cutting control). Normal-pH tenderloins served as a control and had no HPP treatment applied. Following 48 h of dark storage after HPP, tenderloin sections were portioned into 2.4-cm and 1.2-cm steaks for simulated retail display and further laboratory analysis, including objective and subjective color, pH, thiobarbituric acid reactive substances (TBARS), and Warner-Bratzler shear force (WBSF). Objective and subjective color were collected for days 0 through 7 of retail display, pH and TBARS values were found for days 0, 3, and 7, and WBSF were obtained for days 0 and 7. Data were analyzed using the GLIMMIX procedure of SAS 9.4 for the main effect of HPP treatment within day (where applicable) utilizing a randomized complete block design. Mean separation was determined at a significance of a P value less than or equal to .05.

Results: Prior to HPP treatment, there were no differences among dark-cutting samples treatments for lightness, redness, or yellowness. For lightness (L*), there was a treatment effect for all days of retail display (P < .0001). The 450-MPa treatment was the lightest for all days and the non-HPP dark-cutting control was the darkest for all days and similar to the normal-pH control streaks for days 4 to 7 (P < .05). Additionally, there was a treatment effect for redness (a*) values for all retail days (P ≤ .0153), except days 1 (P = .1123) and 2 (P = .068). The 450-MPa group had greater redness values than the non-HPP dark-cutting control for day 0 (P = .0153). However, for days 3 to 7, the 450-MPa treatment had lower a* values than the normal-pH and non-HPP dark-cutting controls and was similar to the 300-MPa treatment (P ≤ .05). Similarly, there was a treatment effect for yellowness (b*) for all days (P ≤ .013). The 450-MPa treatment showed greater yellowness (b*) than the non-HPP dark-cutting control for days 0 to 3, then showed the greatest yellowness for the remainder of the retail display (P < .05). For surface discoloration, there was a treatment effect for all days (P ≤ .0097), except day 0 (P = .2853). The 450-MPa treatment showed the greatest surface discoloration for days 1 to 3, had greater discoloration than the normal-pH and dark-cutting controls, but was no different from the 300-MPa treatment for days 4 to 7 (P < .05). Similarly, there was a treatment effect for color scores and paleness scores for all days (P ≤ .0005; P < .0001). The 450-MPa treatment also exhibited the lowest color score and the greatest paleness scores throughout the retail display (P < .05). Furthermore, the 450-MPa treatment showed the greatest TBARS values for days 3 and 7 (P < .0001). There was no difference between treatments for pH for any of the days (P < .05). Also, the 450-MPa group showed greater WBSF values than the non-HPP dark-cutting control for day 0 (P = .0148). For day 7, the 450-MPa treatment had the greatest WBSF values, the dark-cutting control group had the lowest values, and the normal-pH controls and 300-MPa treatments were intermediate (P < .0001).

Conclusion: When treated at 300 MPa for 90 s, dark-cutting tenderloin steaks had increased lightness values as well as minimal adverse effects on lipid oxidation and tenderness, resulting in steaks more similar to the normal-pH controls than other treatment groups. However, dark-cutting tenderloins treated at 450 MPa for 90 s results in excessive lightening in addition to increased lipid oxidation.

Funding Source: This project was funded in part by the National Beef Cattlemen’s Association.

Keywords: dark-cutting beef, high-pressure processing, color, color labile, tenderloin.

38 Evaluation of Cooked Color and Descriptive Sensory Attributes of Whole Muscle Steaks Under Nitric Oxide Modified Atmosphere and Traditional Packaging Systems

Elizabeth Neal^1,*, Thomas Dobbins¹, Benjamin Carpenter¹, Samantha Barker¹, Sebastian Hernandez¹, Chance Brooks¹, Dale Woerner¹, Jerrad Legako¹, Ranjith Ramanathan², ¹Department of Animal and Food Sciences, Texas Tech University, Lubbock, TX 79415, USA, ²Department of Animal and Food Sciences, Oklahoma State University, Stillwater, OK 74078, USA *elizneal@ttu.edu

Introduction/Objectives: At retail, perceived wholesomeness and freshness of meat products is largely dictated by meat color. Thus, discarded meat at the retail level can largely be attributed to discoloration. Already, a variety of packaging technologies exist that aim to improve discoloration and in turn extend the shelf life of fresh meat products. However, these traditional packaging systems have proven to be detrimental to certain quality factors, indicating the necessity of novel technologies. Therefore, the objective of this study was to compare cooked color development and sensory performance of Longissimus lumborum (LL) and Psoas major (PM) beef steaks in nitric oxide modified atmospheric packaging (MAP) to traditional packaging technologies.

Materials and Methods: Vacuum-packaged beef striploins (n = 13) and whole tenderloins (n = 25) were collected from US Department of Agriculture low-choice carcasses and aged at 0°C to 2°C, in the dark for 7 d. Following aging, subprimals were sliced into 2.54-cm thick steaks representing the LL and PM and assigned to packaging treatments: vacuum (n = 40), polyvinyl chloride overwrap (PVC, n = 40), 80% O₂ to 20% CO₂ (HI-OX, n = 40), 0.4% CO to 30% CO₂ to 69.6% N₂ (CO, n = 40), or 0.4% NO to 99.6% N₂ (NO, n = 40). Steaks designated for MAP were placed into 2.5-cm deep plastic trays and flushed with their designated gas. Packages were then stored for 7 d at 2°C in the dark. After acclimation, samples designated to PVC were removed from vacuum and overwrapped. All samples allotted to cooked color or trained sensory analysis were placed in a simulated retail display for 48 h prior to freezing where samples were maintained at −20°C until further analysis. For all cooked analysis, steaks were cooked to an internal temperature of 71°C on a commercial flat-top grill. Visual color was evaluated on the internal cooked surface by trained panelists (n = 6) using an 8-point scale, where 1 represents very bright red and 8 represents tan to brown. Additionally, external uniformity was evaluated using a 5-point scale, where 1 represents no variation and 5 represents extreme variation. Instrumental color was evaluated using a HunterLab spectrophotometer, where L*, a*, and b* values were recorded for both external and internal cooked surfaces. For descriptive sensory, panelists (n = 6) were trained to evaluate 18 attributes relative to palatability. Data were analyzed as a randomized block design, where packaging type, muscle, and their interactions served as the fixed effects. Peak temperature, session, and order were included in the respective models as covariates. Statistical significance was determined at a P value of less than or equal to .05.

Results: Internal a* values were impacted by the packaging type muscle interaction (P < .001). NO-MAP steaks from both the PM and LL exhibited a redder internal color compared to Rollstock, PVC, CO-MAP, or HI-OX packaged PM steaks and HI-OX samples from the LL; however they were similar in color to LL steaks from Rollstock, PVC, and G2 packages. The packaging type muscle interaction had no impact on internal L* values or external L*, a*, and b* values (P > .05). Additionally, no visual color or sensory traits were impacted by the packaging type muscle interaction (P > .05). However, instrumental and visual color were each impacted by packaging type (P < .05). More specifically, NO-MAP packages were redder on the external cooked surface compared to CO-MAP, HI-OX, Rollstock, and PVC (P < .05), while the latter packaging types had similar a* values (P > .05). Additionally, NO-MAP samples presented slight variation on the external cooked surface compared to all other packaging types (P < .05). CO-MAP, HI-OX, and PVC did not differ and were rated to have no variation (P > .05). Both NO-MAP and CO-MAP packages exhibited a brighter red internal cooked color appearance compared to HI-OX samples, which were tanner to brown (P < .05). External cooked color variation was also impacted by muscle (P < .001), where LL steaks exhibited a greater amount of variation on the external surface than PM steaks. Despite cooked color differences, notable distinctions among NO-MAP samples compared to Rollstock, CO-MAP, or PVC were limited. Nonetheless, scores for beef identity and umami were impacted by packaging type (P < .001), where HI-OX samples were overall less beefy and had less umami than NO-MAP, CO-MAP, Rollstock, or PVC packages (P < .05). Similarly, cardboardy and fishy off flavors were impacted by packaging type (P < .001). HI-OX samples were perceived to be more cardboardy as well as fishier compared to any other packaging type (P < .05). Additionally, HI-OX packages were overall more bitter than Rollstock, PVC, CO-MAP, or NO-MAP packages (P < .05). The cardboardy sensory trait was also impacted by muscle (P < .001), where PM steaks elicited a greater cardboardy off flavor compared to LL steaks.

Conclusion: Generally, NO-MAP samples performed similarly to traditional packaging systems regardless of muscle with the exception being HI-OX packaging and off flavors associated, which were enhanced in the PM. While NO-MAP has a marginal impact on sensory performance of steaks from the LL or PM, NO-MAP also promotes a unique cooked color possessing greater redness. Increased redness on both the external and internal cooked surface warrants further investigation to determine the acceptability of NO-MAP for fresh beef.

Funding Source: Research coordinated by the National Cattlemen’s Beef Association, a contractor to the Beef Checkoff.

Keywords: steaks, nitric oxide, packaging.

39 Color and Oxidative Stability During Retail Display of Ground Beef Incorporating Freeze-Dried Exudate

Benjamin J. Carpenter^1,*, Sabrina E. Blandon¹, Leslie D. Thompson¹, Jerrad F. Legako¹, and Tyson R. Brown², ¹Texas Tech University, Lubbock, TX 79409, USA, ²Cargill, Wichita, KS 67202, USA *Benjamin.Carpenter@ttu.edu

Introduction/Objectives: Currently in the beef industry, exudate is considered a waste byproduct from the freezing, storage, and wet aging of vacuum-packaged cuts. Exudate loss and accumulation can decrease yield and negatively influence consumer perception. While research has attempted to minimize exudate, its use as an ingredient or product enhancer has not been thoroughly evaluated. Research on hemoglobin inclusion in ground beef has demonstrated an ability to inhibit the release of oxidative linear aldehydes while increasing Maillard-derived volatiles. Exudate, which is high in myoglobin, hemoglobin, free iron, and soluble peptides may have a similar effect when freeze dried and added back to ground beef. However, increased free iron could increase oxidation, leading to discoloration and decreased shelf life. Therefore, the objective of this study was to evaluate the performance of freeze-dried exudate (FDE) inclusion in ground beef during retail display through the analysis of instrumental color, descriptive color, surface myoglobin, lipid oxidation, and microbial enumeration.

Materials and Methods: Eight 4.5-kg chubs of 80 to 20 and 8 chubs of 93 to 7 ground beef were purchased from a local purveyor. Chubs were further processed 72 h to 96 h after their initial commercial fabrication. Each chub was designated to different 3.6-kg batches at 0%, 0.5%, 1%, and 2% FDE inclusion (N = 2). Batches were mixed with a hand-crank mixer then formed into 151-g patties using a commercial patty maker. Within each batch, 12 patties were made and designated to 3 different timepoints at 0 h, 48 h, and 96 h of retail display, with 4 repetitions per timepoint per batch (n = 8). Directly after processing, the 0-h patties were sampled for microbial enumeration and homogenized for further analyses. The 48-h and 96-h patties were polyvinyl chloride (PVC) overwrap-packaged and randomly sorted into coffin-style cases with florescent lighting. Temperature was monitored every 12 h (4.1 ± 0.5°C). The patties were removed from the cases at their time points, sampled for microbial enumeration, and homogenized for thiobarbituric acid reactive substances (TBARS) analysis using modified methodology from Luque et al. (2011). Ten grams of each sample were stomached with 90 mL of buffered peptone water. Further dilutions were made, incubated, then enumerated for total aerobic counts, Enterobacteriaceae, and psychrotrophic spoilage microorganisms using the TEMPO system. Samples designated for 96 h were evaluated for color. Instrumental color was evaluated every 12 h using a HunterLab MiniScan EZ 4500. Three scans were taken and averaged for L*, a*, and b* values and were converted to hue and chroma values. Wavelength absorbances were taken to calculate percentage surface deoxymyoglobin, oxymyoglobin, and metmyoglobin using the Krzywicki method. Descriptive color was evaluated by 6 trained panelists every 24 h using percentage surface discoloration and the American Meat Science Association 8-point scale for ground beef display discoloration. Statistical analyses were done in R Studio using a generalized least-squares model fitted with restricted maximum-likelihood and correlation for repeated measures of batch/sample with case as a covariate. Different variance structures were selected based on the lowest Bayesian information criterion score, and nonsignificant interactions were removed from the model. Least-squares means were compared using Tukey’s test and Satterthwaite degrees of freedom. Significance was determined at α less than or equal to 0.05.

Results: For instrumental color, lean level-by-time had an interaction for all measurements (P < .001), and the percentage FDE had a main effect on all instrumental color measurements (P < .001), except hue angle (P = .613) as well as an FDE-by-lean level interaction for L* values (P = .009). The L* values indicate that both lean levels darkened over the display period (P < .05) as well as with increased percentage FDE (P < .05), but the 80% lean was initially lighter (P < .05). Similarly, both lean levels decreased in a* values (redness; P < .05) and increased in b* values (yellowness; P < .05) over time. For a*, b*, and chroma values 0%, 0.5%, and 1%, FDE were similar (P > .05), but 2% FDE had decreased values (P < .05), meaning that they were less saturated and red/yellow. The discoloration indicated by the instrumental color data is further reflected by the descriptive color evaluation, where color score had 3 two-way interactions with FDE, lean level, and time (P < .001) and did not have a 3-way interaction (P = .113). However, percentage discoloration only had an FDE-by-time and lean-by-time interaction (P < .001). The discoloration apparent from the instrumental and descriptive color data can be explained by the myoglobin percentages of the samples. Both metmyoglobin and oxymyoglobin had a lean level-by-time interaction (P < .001) and a percentage FDE main effect (P < .001). Like the a* values, only 2% FDE was different for oxymyoglobin with a decreased percentage (P < .05). Alternatively for percentage metmyoglobin, both 0% and 2% FDE were different, with 0% having the least metmyoglobin and 2% having the most (P < .05). For deoxymyoglobin, an FDE-by-lean level-by-time interaction was noted (P = .010). For the microbial enumeration, there was an FDE-by-time interaction for total aerobic counts (P < .001), Enterobacteriaceae (P = .002), and psychrotrophs (P < .001). For Enterobacteriaceae, the FDE percentages within the same timepoint were not different (P > .05), but the Log CFU/10 g increased with time (P < .05). However, this is not the case for total aerobic plate count which had 1.9 and 1.8 less Log CFU/10 g for 0% FDE at the initial and middle timepoints (P < .05), as well as pyschrotrophs with 1.8 and 1.2 less Log CFU/10 g for 0% FDE at the initial and middle timepoints (P < .05). The TBARS data had an FDE-by-time interaction (P = .001), where FDE percentages within the initial and middle timepoint were not different (P > .05). However, 0% FDE had greater mg/kg equivalents of malondialdehyde than 2% FDE at the final timepoint (P < .05). Additionally, 2% FDE at the final timepoint was not different from the 2% FDE at the middle timepoint (P > .05).

Conclusion: Although myoglobin oxidation may increase with FDE inclusion, leading to less redness and increased discoloration during retail display, lipid oxidation appears to decrease with FDE inclusion as indicated by the TBARS values. The myoglobin percentages follow the expected trend, where oxymyoglobin is converted to metmyoglobin over the retail display leading to less redness and more discoloration. Additionally, increased percentage FDE may increase myoglobin oxidation, likely induced by the prooxidative effect of free iron, which would also promote increased lipid oxidation. However, the increased heme content may further react with primary lipid oxidation products such as malondialdehyde. The decrease in TBARS indicates heme-aldehyde binding, supporting the theory of FDE’s ability to alter flavor development. Therefore, further research is needed to characterize the volatile and sensory profile of ground beef with FDE inclusion; however, concerns with increased microbial counts and discoloration should also be addressed, and alternative packaging could be investigated.

Keywords: hemoglobin, myoglobin, oxidation, shelf life, spoilage.

40 The Study on the Regulatory Effect of Hesperidin on the Physicochemical Properties of Pork Myofibrillar Proteins Under Oxidative Stress

Zhimin Cai¹, Hanlin Wu¹, Manmin Xu², Xingzhong Zhang¹, Tao Wu¹, Dong Zhang¹, Ping Liu¹, Jie Tang¹, and Wenjie Shao^1,*, ¹Xihua University, Chengdu, Sichuan 610039, China, ²Huazhong Agricultural University, Wuhan, Hubei 430070, China *wenjie.shao@mail.xhu.edu.cn

Introduction/Objectives: As a major meat source, pork contains 18% to 20% protein, with sarcoplasmic proteins (SP) accounting for 30% to 35% of total proteins. These water-soluble proteins play a decisive role in meat quality through myoglobin-mediated color development mechanisms. However, oxidative degradation during processing and storage triggers functional deterioration of SP, resulting in meat discoloration and textural deterioration. This study proposes supplementing hesperidin from citrus extract as an antioxidant strategy to stabilize SP. As the principal bioactive flavonoid in citrus extracts, hesperidin demonstrates multifaceted functionalities, including anti-inflammatory, antioxidant, and antimicrobial effects. Hesperidin is also well known for its lipid metabolism modulation capabilities and exhibits remarkable free radical scavenging capacity. This study used pork SP (PSP) as the research object and measured the color difference of PSP and oxidation indexes such as particle size, ζ potential, and dipolytyrosine level to explore the effects of hesperidin supplementation on the physicochemical properties of PSP under oxidative stress.

Materials and Methods: Six treatment groups were tested: control (no oxidative stress), 0%, 1.5%, 3%, 4.5%, and 6% hesperidin (oxidative stress applied). One-hundred and fifty grams of defatted pork from fresh tenderloin was minced and mixed with 0.02 M phosphate buffer (pH = 7.0) at a 1 to 4 (w/v) ratio. The mixture was homogenized twice intermittently (6000 rpm, 60 s each cycle) and centrifuged at 4°C (4000 × g, 15 min) to collect the supernatant. Protein concentration was determined using the biuret method. The SP solution was adjusted to 5 mg/mL, followed by the addition of the Fenton reagent (0.01 mM FeCl₃/0.1 mM ascorbic acid/5 mM H₂O₂). The reaction was oscillated at 4°C for 24 h and terminated with 1% butylated hydroxytoluene. Color parameters were measured using a colorimeter (D65 illuminant) with a protein concentration of 2.5 mg/mL. Ultraviolet (UV) spectrophotometry samples were diluted to 0.125 mg/mL using 0.02 mol/L SP buffer (SPB) and scanned from 200 nm to 340 nm in a quartz cuvette. Quantitative analysis was performed at 280 nm. Measurement Samples were diluted to 0.1% of the original concentration using 0.02 mol/L SPB and equilibrated at 25°C for 120 s in a ζ potential analyzer. Samples were then adjusted to 0.1% and analyzed using a laser particle size analyzer with refractive indices set to 1.520 (protein) and 1.333 (water). Samples were adjusted to 0.1 mg/mL using 0.02 mol/L SPB and analyzed with emission wavelength 420 nm, excitation wavelength 325 nm, slit widths 10 nm, and voltage 400 V. Over 6 scans were performed to record relative fluorescence intensity. Samples (0.1 mg/mL) were excited at 295 nm with slit widths of 10.0 nm, scan rate of 1,200 nm/min, and voltage of 400 V. Fluorescence spectra were recorded between 310 nm and 400 nm. Data processing was performed using Excel for data organization and mean values and relative SD values calculation. Statistical analysis was conducted using SPSS 26, and graphical plotting was accomplished with Origin 2021 software. Duncan’s multiple range test was applied for significance analysis, with P value of less than .05, indicating statistically significant differences.

Results: Hydroxyl radical oxidation significantly altered the color parameters of SP. Compared with the control (no oxidative stress applied) and 0% hesperidin (with oxidative stress), all the values were significantly different (P < .05). The a*, b*, and C* values decreased by 62.1%, 18.1%, 25.3%, while the L* and H* value increased by 12.8% and 18.3%, respectively. The addition of 6% hesperidin markedly reversed these oxidative effects, restoring the C* value to 15.29 and the H* value to 74.01. Within the wavelength range of 200 nm to 340 nm, all groups exhibited a trend of initial sharp decline followed by a gradual rise in absorbance. The structural changes of SP after hesperidin addition gradually become similar to the control group, as the concentration of hesperidin increased. Adding 6% hesperidin restored the absorbance to levels comparable to the control group. Hydroxyl radical oxidation significantly reduced the ζ potential of SP from 8.04 mV to 5.77 mV. However, the addition of 6% hesperidin significantly (P < .05) reversed this trend compared to 0% hesperidin, and the ζ potential value of 6% hesperidin was not significantly different (P > .05) from that of the control. Hydroxyl radical oxidation significantly increased the average particle size of SP. The addition of 6% hesperidin significantly reduced (P < .05) the particle size compared with 0% hesperidin. Hydroxyl radical oxidation significantly increased the dityrosine fluorescence intensity from 205 AU (control) to 245 AU (0% hesperidin). However, adding the increasing concentration of hesperidin markedly inhibited this process, and adding 6% hesperidin significantly (P < .05) reduced the fluorescence intensity to 211 AU compared to 0% hesperidin. The data indicate that the 16.6% free radical scavenging capacity was achieved with 6% hesperidin. Compared with the control group and 0% hesperidin, hydroxyl radical oxidation caused a 23.4% decrease in the intrinsic fluorescence intensity of SP at 340 nm, indicating alterations in the tryptophan microenvironment due to oxidation-induced protein aggregation. However, the addition of 6% hesperidin reduced the 23.4% decrease to only 0.32%, indicating that the addition of hesperidin alleviated the alterations.

Conclusion: This study evaluated the antioxidative effects of hesperidin (0, 1.5, 3, 4.5, and 6%) on PSP using a hydroxyl radical oxidation model. Key findings include the following: 1) color stability, hesperidin restored chroma (C*) to 15.29 and hue angle (H*) to 74.01; 2) colloidal stability, it recovered ζ potential and enhanced protein-water interactions; 3) aggregation suppression, particle size growth was inhibited with dityrosine formation reduced; and 4) conformational protection, intrinsic fluorescence decline was limited to 0.32% and preserved aromatic residue microenvironments. To conclude, hesperidin delayed the oxidation of SP under simulated oxidative stress. These findings support hesperidin’s potential as a natural antioxidant for use in the meat preservation process. Future studies should employ molecular docking and dynamic simulation to clarify structure–activity relationships between hesperidin and SP to further discover the hesperidin’s antioxidant mechanisms.

Funding Source: This project was funded by the Talent Project of Xihua University (grant number Z222087).

Keywords: hesperidin, sarcoplasmic protein, oxidative stress.

41 Citrus Fiber Alters Dynamic Rheology, Texture, and Water-Holding Capacity of Chicken Wooden Breast Breakfast Sausage Batter

Muhammad Junaid Nawaz^1,*, Harshavardhan Thippareddi², Brian Bowker³, William Kerr⁴, Dewey Hamilton Thomas¹, J. Anna Scott¹, Clint Lee¹, and Alexander M. Stelzleni¹, ¹Department of Animal and Dairy Science, University of Georgia, Athens, GA 30602, USA, ²Department of Poultry Science, University of Georgia, Athens, GA 30602, USA, ³US Department of Agriculture, Agriculture Research Service, US National Poultry Research Center, Athens, GA 30605, USA, ⁴Department of Food Science & Technology, University of Georgia, Athens, GA 30602, USA *junaidnwz@hotmail.com

Introduction/Objectives: Wooden breast (WB) has become a crucial challenge to the profitability of the poultry industry due to its detrimental effects on meat quality. Altered protein composition in WB-affected meat displays adverse textural properties and a reduced water-holding capacity (WHC). Further processed products are being explored to improve the utility of WB meat. However, WB meat batter results in poor processability compared to normal chicken due to protein dysfunction, resulting in mushy and watery batter formation. Adding clean label functional ingredients such as citrus fiber in meat batters was reported to affect the textural properties and WHC. The study objectives were to evaluate citrus fiber’s influence on rheological, textural, and water-holding properties of WB meat batter to improve processability.

Materials and Methods: WB and normal breast fillets (227 kg) were collected 4 h postmortem, over 3 replications, from a commercial poultry processing plant and transported on ice to the University of Georgia Meat Science & Technology Center. Collected breast fillets were individually identified and segregated into normal and severe WB by visual characterization and manual palpation. The normal and WB were vacuum packaged in batches and stored at −25°C plus or minus 2°C until further processing. For each replication, the breasts were thawed for 32 h plus or minus 4 h prior to further processing into breakfast sausages. Normal and WB meat were separately coarse ground (1.27 cm), and then 6 batches (11.34 kg/batch) were formed: 2 batches each for 0% WB (WB0), 50% WB (WB50), and 100% WB (WB100). For 1 batch of each WB percentage category, 0.1134 kg (1%) of the meat block was replaced with citrus fiber, resulting in 3 batches of each WB category containing fiber (F) and 3 batches without fiber (NF). Blend 10 (227 g) sausage seasoning (A.C. Legg, Inc., Calera, AL) and 3% water was mixed into each batch for 3 min using a reverse action paddle mixer and fine (0.48 cm) ground to form the final breakfast sausage batters. The batters were extruded using a vacuum stuffer through a single slot (Colosimo 3/8”) die to form 61.2-cm long by 10.2-cm wide by 9.5-mm thick strips of breakfast sausage patties. Strips were frozen (−30 ± 2°C) for 80 min and then cut into 10.2-cm by 10.2-cm by 9.5-mm square patties. Five patties per treatment within each replication were randomly selected, vacuum packaged, and frozen for WHC, dynamic rheology, and texture profile analyses. Data were analyzed as a randomized complete block design in a 2 by 3 factorial arrangement using Proc-MIXED procedure of SAS 9.4. Fiber inclusion (FIB) and WB status were the fixed effects, replication was the random term, and chicken breakfast sausage patty was the experimental unit.

Results: There were no WB by FIB interactions (P > .05) for the complex modulus (G*), storage modulus (G'), and loss modulus (G”). Irrespective of FIB, WB100 had the smallest (P < .01) G* value, followed by WB50 and WB0, explaining the decreased total resistance to deformation with increased WB level. Fiber-added breakfast sausage batters demonstrated enhanced (P < .01) total resistance to deformation (greater G*), irrespective of the WB level. The G’ decreased (P < .01) with increased WB percentage in breakfast sausage batters, illustrating weaker and softer batter associated with increased WB content, while fiber addition increased G’ of batters. Reduced G” values were shown by WB100 batters compared to WB50 and WB0, depicting the decreased spreadability associated with increased WB content in batters. Fiber addition increased G” of the batters irrespective of WB level. There were WB by FIB interactions (P < .01) for the damping factor (tan δ). The NF-WB0 had a smaller (P < .01) value for tan δ than NF-WB100, indicating its stronger internal structure and more elastic (solid-like) behavior. The F-WB0 had a lower (P < .05) tan δ than F-WB100 but was not different (P > .05) from NF-WB100. Fiber incorporation made breakfast sausage batters less elastic (P < .01). Raw breakfast sausage batters had WB by FIB interactions (P < .01) for adhesiveness but not (P > .05) for hardness, resilience, springiness, and gumminess. The adhesiveness exhibited by F-WB50 was not different (P < .01) from NF-WB0. No fiber WB0 exhibited greater adhesiveness than NF-WB100, but there was no difference (P > .05) compared to NF-WB50. Irrespective of the fiber addition, WB0 batter was harder, more resilient, and gummier (P < .01) than WB50 and WB100, while woodiness did not affect (P > .05) springiness. FIB resulted in more adhesive (P < .01) batters, increased (P < .01) springiness, and decreased (P < .01) resilience without affecting (P > .05) hardness and gumminess. FIB improved (P < .01) cook yield by 1.92%, irrespective of the WB percentage, whereas WB50 had 1.77% and WB100 had 3.45% greater (P < 0.01) cook loss than WB0, irrespective of the FIB.

Conclusion: Overall, fiber addition to breakfast sausage formulations made with WB meat resulted in a meat batter with increased resistance to deformation (greater G*), increased firmness (greater G'), and decreased elastic behavior (greater tan δ). As a result of these changes to the batter, breakfast sausages that included citrus fiber in the formulation were more adhesive and springier, less resilient, and had an improved cooking yield.

Funding Source: US Department of Agriculture, National Institute of Food and Agriculture.

Keywords: broiler, fiber, batter, rheology, myopathy.

42 Effect of Nitrite Source and Reducing Compounds on Cured Color Development in an All-Beef Model System

Leila G. Venzor^*, Grace C. Johnson, Ashley A. Hahn, Benjamin L. Weinandt, Jordan C. Wicks, and Gary A. Sullivan, University of Nebraska–Lincoln, Lincoln, NE 68588, USA *lvenzor3@unl.edu

Introduction/Objectives: Sodium nitrite, sodium erythorbate, and ascorbic acid have been used as the primary curing and reducing agents in cured meat products due to their efficacy in producing consistent cured color, flavor, and imparting preservative properties. Growing consumer trends demanding naturally derived ingredients have led to use of celery juice and acerola in alternative curing. More recently, other alternative plant sources have been adopted. Prior research has reported varying effectiveness of these natural alternatives depending on their sources, composition, and interaction with natural or synthetic reducing agents. Therefore, this study aimed to investigate the combined effects of nitrite source and reducing compound on cured color development, residual nitrite levels, and pigment formation, providing insights into their use in natural and conventional curing strategies in an all-beef emulsion system.

Materials and Methods: Fresh beef top round was trimmed free of external fat and ground (5 mm) at the Loeffel Meat Laboratory. Treatments were assigned in a 3 × 2 factorial arrangement to evaluate the effect of nitrite source (156 ppm) (sodium nitrite, celery powder [SafePlate CP300, Wenda Ingredients, Naperville, IL], or beet powder [SafePlate BP300, Wenda Ingredients, Naperville, IL]) and addition of reducing compounds (495 ppm ascorbic acid or molar equivalent) (no reducing compound or reducing compound from either sodium erythorbate or acerola [SafePlate ACP34, Wenda Ingredients, Naperville, IL]) on residual nitrite and cured color development in a beef model system. Ground beef (680 g), salt (13.6 g), and ice (136 g) were added to a RoboCoupe food processor with respective nitrite by reducing compound treatments, chopped for 30 s, scraped, and chopped for an additional 30 s. The resulting emulsified batters were placed in 5 mL to 100 mL glass beakers, pressed with a rounded spoon to remove air pockets, covered in plastic wrap, and placed in a cooler (3°C) for 30 min. Subsamples of batter were smeared onto a flat-bottom weigh boat for initial raw color evaluation (L*, a*, b*). Samples were cooked in a water bath (40°C) for 30 min and transferred to an 80°C water bath for an additional 30 min to reach a final temperature of 71°C. Samples were cooled in an ice water bath for 30 min and kept under refrigeration. The following day, beaker sausages were sliced into 4 medallions and cooked color (L*, a*, b*) was measured in triplicate. Absorbances of cured and total meat pigments were measured at 540 nm and 640 nm, respectively (DU 800 Spectrophotometer, Beckman Coulter, Fullerton, CA). Residual nitrite concentrations were measured (540 nm), and concentrations of residual nitrite were determined based on a standard curve. Three full replicates were produced. Data were analyzed as a randomized complete design using PROC GLIMMIX of SAS (version 9.4) for interactions and main effects of nitrite source and addition or absence of a reducing compound.

Results: There was no interaction of nitrite source by reducing compound (P = .43) for any parameter measured. Nitrite source (P = .17) did not impact the development of total meat pigment, cured pigment, or residual nitrite, though there was a tendency (P = .0569) for total meat pigment to be higher with sodium nitrite (145.8 ppm) than with beet powder (123.1 ppm) and with celery powder (136.9 ppm) intermediate. Treatments with reducing compounds had lower total meat pigment (P = .0173) but higher cured (P = .0296) and percentage of cured pigment (P < .001) compared to those without reducing compounds, regardless of nitrite source. Additionally, residual nitrite was lower when a reducing agent was used (P = .004). No significant differences (P = .38) were observed in initial raw color values (L*, a*, b*) for any treatments. Nitrite source did not significantly impact any objective color measurements; however, use of a reducing agent significantly increased redness (P < .0001) of final cooked color in the all-beef model system.

Conclusion: The results of this study indicate that formulas including reducing agents, regardless of nitrite source, had improved cured meat characteristics. This suggests that the nitrite sources used had an equal impact on cured color development, and naturally sourced curing agents were interchangeable with synthesized sodium nitrite in an all-beef model system. Moreover, the importance of using a reducing agent is clear, regardless of source. These findings show that naturally sourced nitrite sources and reducing agents have reached more equivalence to synthetic sources.

Keywords: alternative curing, cured color, beet root, celery juice, acerola.

43 Analysis of Objective and Subjective Sensory Effects of Injected Sodium Bicarbonate of Cow Longissimus Lumborum

Daniel D. Raab^*, Ty E. Lawrence, Loni W. Lucherk, and Trent E. Schwartz, Department of Agricultural Science, West Texas A&M University, Canyon, TX 79016, USA *ddraab1@buffs.wtamu.edu

Introduction/Objectives: While previous research has evaluated the impact of sodium bicarbonate on beef and produced positive results by increasing tenderness, minimal research has been conducted on the injection of sodium bicarbonate into whole muscle beef products. With tenderness being one of the most important sensory traits for consumers, there is demand in the market for methods to produce more tender beef products. Cow striploin steaks are generally tougher than fed-beef striploins. Injecting ingredients such as sodium bicarbonate provides potential to add value via increased tenderness to lower value beef items, such as cow striploins. Therefore, the objective of this study was to determine the influence of inclusion of a sodium bicarbonate injection on sensory characteristics and objective tenderness in underutilized beef products such as cow striploins.

Materials and Methods: Eighteen denuded cow Longissimus lumborum (IMPS #180, PSO 4) were transported to the West Texas A&M University Caviness Meat Science & Innovation Center and aged for 10 d under vacuum. The anterior wedge portion and posterior vein steaks were removed, then striploins were cut into anterior and posterior portions. Strip halves were randomly designated to 1 of 4 treatments: 2 sodium bicarbonate treatments (0.5% [HALFp], 1.0% [ONEp]), a water treatment (H₂O), and a noninjected control (CON) utilizing an incomplete block design with a 2 by 2 factorial arrangement. A multineedle injector was used to enhance strip halves to a targeted 15% inclusion with an average of 8% inclusion. After injection, striploin sections were immediately resealed in vacuum packaging and allowed 4 d to rest and equilibrate. At the completion of the 14-d total age and rest time, striploin halves were cut into six 2.54-cm thick steaks (3 for subjective descriptive sensory analysis and 3 for objective tenderness determinations). Upon fabrication, steaks were vacuum packaged and frozen until further analysis. Samples were allowed 24 h to 26 h to thaw at 2°C to 4°C and weighed just prior to cooking. Steaks were cooked to a target internal temperature of 71°C and evaluated by a descriptive trained panel and analyzed for Warner-Bratzler shear force (WBSF). Panelists were trained according to the American Meat Science Association Research Guidelines for Cookery, Sensory Evaluation, and Instrumental Tenderness Measurements of Meat. Additionally, panelists were trained for sensory characteristics of soapy/alkaline flavor, soapy odor, and beef odor. Nine trained panels were conducted where 1 sample representing each of the 4 treatments was served to a minimum of 6 trained panelists. Samples were served under red light, emitting diode lights to mask color variation among samples during 30 min panel sessions. Panelists evaluated each sample for beef flavor identity, bitter, overall tenderness, overall juiciness, beef odor, soap odor, and soapy/alkaline flavor. Data were analyzed using mixed models. Injection treatment was the fixed effect, percentage pump of each half was used as a covariate, and strip, anterior or posterior half, peak temperature, panel order, and panel were used as random effects.

Results: No treatment differences were observed for cook loss (P = .515), beef odor (P = .140), or overall juiciness (P = .620). When evaluated for soapy/alkaline aroma, ONEp and HALFp, had the highest (P = .002) off odors, whereas H₂O enhanced striploins had the least soapy/alkaline odor. Overall tenderness was impacted (P < .001) by treatment. ONEp and HALFp were more tender than H₂O, which was more tender than CON. Additionally, the H₂O treatment was highest (P < .001) for beef flavor identity and beef flavor intensity, and ONEp was the lowest for beef flavor identity and intensity. When evaluating soapy/alkaline flavor, ONEp steaks had the most (P < .001) soapy/alkaline flavor, HALFp and CON were intermediate, and H₂O was the least soapy/alkaline in flavor. Additionally, ONEp samples had more bitter off flavors (P = .044) than H₂O. Lastly, no difference was observed for WBSF (P = .217) among treatments.

Conclusion: Results suggest that ONEp striploin halves and HALFp striploin halves were positively and negatively impacted by the injection of sodium bicarbonate. Strips injected with H₂O and CON strips were similar for sensory outcomes, cook loss, and WBSF. While there were prevalence of soapy/alkaline aromatics and a reduction of typical beef flavor and beef flavor intensity within cow striploins that were injected with sodium bicarbonate, sodium bicarbonate may be a viable alternative method for tenderness improvement of typically tougher, lower value beef products.

Funding Source: West Texas A&M University Beef Carcass Research Center.

Keywords: beef, palatability, tenderness, enhanced.

44 Physicochemical Properties of Beef Jerky: Impact of Conventional Cooking and Ultraviolet-A Light Dehydration

Sajad Karami^1,*, Mohammed A. AlRuzzi¹, Chandler D. Stafford¹, Sulaiman K. Matarneh¹, and Luis J. Bastarrachea^1,2, ¹Department of Nutrition, Dietetics and Food Sciences, Utah State University, Logan, UT 84322, USA, ²Department of Biological Engineering, Utah State University, Logan, UT 84322, USA *sajad.karami@usu.edu

Introduction/Objectives: Food dehydration has been used for centuries as an effective preservation method. Today, various dehydration techniques are available, each with its advantages and limitations. Many conventional methods rely on high temperatures or significant energy input, which can lead to economic and environmental concerns. Additionally, exposure to high temperatures can degrade essential nutrients, such as vitamins and aromatic compounds, affecting the overall quality of the final product. Beef jerky, a widely consumed dried meat product, is made by cooking and drying beef to enhance flavor and extend shelf life. Traditional methods, such as hot-air drying, are effective but require high energy consumption and may negatively impact texture, color, and nutritional value. As the food industry seeks sustainable alternatives, ultraviolet-A (UV-A) light dehydration has emerged as a promising nonthermal technique. This study compares conventional cooking and drying with UV-A light dehydration to evaluate their effects on the physical properties of beef jerky.

Materials and Methods: Beef top round subprimals of uniform quality and weight were sourced from a local supplier, trimmed, and sliced along the muscle fibers into consistent strips. These strips were mixed with a dry cure containing sodium nitrite, erythorbate, and salt, and then incubated at 4°C for 20 h. The marinated beef was divided into 2 groups for either conventional smokehouse drying or UV-A light dehydration. Three independent replicates were prepared per treatment to ensure statistical validity. Water activity (a_w) and microbial load were assessed prior to drying to establish baseline data. Conventional beef jerky was dried in a smokehouse oven at 93.3°C with 10% relative humidity for 55 min, with adequate ventilation. The target a_w was maintained between 0.83 and 0.85. After drying, samples were cooled, vacuum sealed, and stored at 4°C until further analysis. UV-A light dehydration was carried out in a custom-built chamber equipped with controlled airflow and temperature. Marinated beef strips were arranged on a stainless-steel platform, and moisture loss was monitored over 10 h. The dehydration process was modeled using Weibull distribution. This technique was selected for its energy efficiency, lower environmental impact, and potential to preserve nutritional and textural qualities. A chromameter was used to measure L* (lightness), a* (redness), and b* (yellowness) values. Calculations of color change (ΔE), chroma (C*), hue angle (h°), and browning index (BI) were also performed. Jerky samples were exposed to controlled humidity environments for 35 d using the isopiestic method. Sorption behavior was analyzed with a semiempirical double power-law model. Attenuated total reflectance Fourier-transform infrared spectroscopy was used to detect chemical structural changes, sampling multiple locations per sample to compare the 2 drying methods. Microstructural features were examined using scanning electron microscopy (SEM). Freeze-dried samples were gold-palladium coated and imaged under high vacuum conditions. a_w was measured at defined intervals using a calibrated a_w meter. Microbial counts were assessed by plating diluted samples on plate count agar and incubating for 48 h.

Results: The initial moisture content of marinated beef jerky was 0.71 kg H₂O/kg wet sample. After 6 h of UV-A light dehydration, it decreased to 0.29 kg H₂O/kg wet sample, reaching equilibrium at 0.16 kg H₂O/kg wet sample after 10 h. The dehydration process followed the Weibull model, with a high correlation (R² = .993), indicating a predictable drying pattern. The a_w decreased from 0.97 to 0.80 within 6 h, showing a strong linear correlation with time. The sorption isotherms of both UV-A light-dehydrated and conventionally cooked beef jerky were similar, suggesting comparable water reabsorption tendencies. This indicates that UV-A light dehydration does not significantly alter the jerky’s ability to retain or release moisture compared to conventional cooking. The drying method significantly influenced the color of the beef jerky. Fresh marinated samples had the highest brightness (L*), while UV-A light-dehydrated jerky was the darkest. The redness (a*) was highest in fresh samples, followed by conventionally cooked, and lowest in UV-A light-dehydrated jerky. Similarly, yellow hue (b*) was highest in fresh samples and lowest in UV-A light-dehydrated jerky, giving it a slightly bluer appearance. The overall ΔE was greater for UV-A light-dehydrated samples compared to conventionally cooked jerky. The BI indicated less browning in UV-A light-dehydrated jerky compared to cooking. The h° confirmed variations in color tones, with fresh beef being more orange-red, UV-A light-dehydrated jerky appearing redder, and conventionally cooked samples having a brighter orange hue. The ΔE suggest that UV-A dehydration results in a darker and duller appearance, possibly due to the absence of heat-induced pigment transformations. SEM imaging revealed structural differences between fresh-, conventionally cooked-, and UV-A light-dehydrated beef jerky. Fresh and marinated samples had compact, circular muscle fibers. Cooking led to extensive cracking due to rapid moisture loss, while UV-A dehydration preserved a denser and more uniform structure with fewer cracks. This suggests that UV-A light dehydration maintains muscle fiber integrity better than conventional cooking. UV-A light dehydration reduced microbial load by 1.35 Log (CFU/g dry solids) after 5 h, while cooking achieved a greater reduction of 2.93 Log (CFU/g dry solids). Both methods enhanced shelf stability, though cooking was more effective due to higher temperatures. However, UV-A irradiation still contributed to microbial inactivation, improving food safety.

Conclusion: This study confirms that UV-A light dehydration is an effective method for producing beef jerky with desirable physical characteristics. The process, which takes approximately 4.5 h, preserves microstructural integrity better than conventional cooking, as shown by SEM analysis. Although conventional cooking achieved a higher microbial reduction (2.93 Log CFU/g vs. 1.35 Log CFU/g), the 1.58 Log difference highlights the enhanced lethality of thermal processing. However, UV-A dehydration still reduced microbial load effectively when a_w dropped below 0.85. Color analysis revealed that UV-A dehydration results in a darker, less red appearance and a lower BI, likely due to pigment stabilization differences. Nevertheless, its moisture sorption behavior was comparable to traditionally dried jerky. UV-A dehydration offers a nonthermal, energy-efficient alternative with potential advantages in preserving meat texture and quality. These unique product attributes may appeal to niche consumer markets, supporting broader adoption of sustainable dehydration technologies in the meat processing industry.

Figure 1.

M. C. W. B. versus time during UV-A light dehydration of beef jerky (A); Dehydration kinetics data of UV-A light dehydrated beef jerky fitted with https://www.sciencedirect.com/science/article/pii/S0960308524001573#eqn0005 Eq. 1 (B); Linear relationship between aw and time during UV-A light dehydration (C); Moisture sorption isotherms of conventionally cooked and UV-A light dehydrated beef jerky fitted with https://www.sciencedirect.com/science/article/pii/S0960308524001573#eqn0035 Eq. 7 (D).

Figure 2.

Ultraviolet-A light dehydration of beef jerky. UV-A, ultraviolet-A.

Table 1.

Surface colorimetric analysis of fresh marinated, ultraviolet-A light-dehydrated, and conventionally cooked beef jerky samples.

Treatment	Color	L*	a*	b*	ΔE	BI	h°	C*
Fresh marinated beef sample		35.3 ± 1.5a	17.6 ± 2.0a	9.8 ± 0.8a	0.0 ± 0.0a	36.0 ± 4.2a	29.1 ± 1.3a	20.2 ± 2.1a
UV-A light-dehydrated beef jerky		25.7 ± 0.8b	7.8 ± 1.3b	2.5 ± 0.7b	15.6 ± 1.4b	21.8 ± 3.3b	17.3 ± 2.3b	8.2 ± 1.4b
Conventionally cooked beef jerky		28.6 ± 0.8c	10.0 ± 1.2c	6.5 ± 1.2c	10.9 ± 1.5c	26.0 ± 2.8c	32.9 ± 2.2c	11.9 ± 1.6c

• ΔE, color change; a*, redness; b*, yellowness; BI, browning index; C*, chroma; h°, hue angle; L*, lightness; UV-A, ultraviolet-A.

• Treatment with the same superscript letter within the same column are not significantly different (P < .05).

Funding Source: This work is supported by the US Department of Agriculture National Institute of Food and Agriculture, Agriculture and Food Research Initiative project number 2021–09342. The authors thank the Ambassador Ardeshir Zahedi International Endowment Scholarship and Dr. Niranjan R. Gandhi and Mrs. Josephine N. Gandhi Graduate Assistantship by Utah State University.

Keywords: meat processing, beef jerky, food dehydration, nonthermal technologies, UV-A light dehydration.

45 Impact of Phosphates as an Enhancement on the Yield and Quality of Sectioned and Formed Ham, Bacon, and Hotdogs

Bryant Sawin¹, Ambri Harrigal^1,*, Olivia Ron², Trent Schwartz¹, Loni Lucherk¹, and Ty Lawrence¹, ¹Department of Agricultural Sciences, West Texas A&M University, Canyon, TX 79016, USA, ²ICL Group, St. Louis, MO 63141, USA *aharrigal@wtamu.edu

Introduction/Objectives: Phosphates are great chelators that help improve the yield and quality of meat by altering the overall pH. Additionally, phosphates are commonly used to improve product water-holding capacity and aid against free radicals that produce rancid flavors, thus increasing shelf life. The objective of this study was to quantify the effects of phosphate treatments upon production yield and quality outcomes when used in restructured hams, bacon, and hotdogs.

Materials and Methods: Hams were produced using 1 of 4 phosphate (0.48% inclusion) treatments ([1] no phosphate control; [2] sodium tripolyphosphate (STPP); [3] Brifisol 512, a blend of 2 phosphates with a pH range of 8.7–9.3; or [4] Brifisol 550, a blend of 3 phosphates with a pH range of 11.4–12.0). Trimmed and macerated ham pieces were vacuum tumbled with a brine (water, honey, potassium diacetate, salt, sugar, liquid dextrose, phosphate, sodium erythorbate, sodium nitrite) for 30 min at 8 rpm. Ham was stuffed into casings, smoked/cooked (1.5 h at 76.7°C then fully cooked to 71. 1°C at 82.2°C), chilled (−1.1°C), sliced 3.18-mm thick, and vacuum packaged. Bacon was produced from bellies injected with 1 of 4 phosphate (0.354% final phosphate inclusion) treatments ([1] no phosphate control; [2] STPP; [3] Brifisol 450, a blend of 3 phosphates with a pH range of 7.2–7.8; or [4] Brifisol 460, a blend of 3 phosphates with a pH range of 6.2–6.8). Bellies were injected (13%) with a brine (water, sugar, salt, phosphate, sodium nitrite, sodium erythorbate) and smoked/cooked (smoked for 1.5 h at 54.4°C and cooked to an internal of 62.2°C at 63.3°C) before being chilled (−1.1°C), sliced, and vacuum packaged. Hotdogs were produced using 1 of 3 phosphate (0.376% phosphate inclusion) treatments ([1] no phosphate control, [2] STPP, or [3] Brifisol 450). Pork, beef, water, salt, seasoning, liquid sorbitol, phosphate, and sodium nitrite were emulsified in a bowl chopper, stuffed into plastic casings, and cooked (smoked for 0.91 h at 65.6°C and cooked to an internal of 71.1°C at 77.8°C), chilled (−1.1°C), peeled, and vacuum packaged. Samples from each batch of ham, bacon, and hotdogs were analyzed for aerobic plate count (APC), thiobarbituric acid reactive substances (TBARS), and evaluated for L*, a*, and b* during a 10-d simulated retail display every 30 d for 180 d after production. All products were evaluated by a trained sensory panel for sensory characteristics. Mixed models were used, phosphate treatment and time in refrigerated storage were fixed effects. Single degrees of freedom contrasts tested Brifisol vs. STPP and phosphate treatments vs. control.

Results: No difference was detected in ham TBARS (P = .68), hardness/firmness (P = .09), or saltiness (P = .09) between treatments. Ham brine pH differed (P < .01), with Brifisol 550 having the highest pH (7.98) compared to STPP (6.19), Brifisol 512 (6.00), and control (5.34). Brifisol 550-treated hams had higher APC than those treated with STPP (P = .02). Control hams had lower (P < .01) aroma scores, more rancid odor, lower ham flavor, more rancid flavor, less juicy, and the lowest sensory acceptability. Hams aged 1 to 3 mo had higher (P < .01) ham flavor than those aged 5 mo or 6 mo. Sweetness varied among treatments (P < .01). Brifisol 512 was sweeter than the control. Rancid flavor was higher in hams aged 5 mo or 6 mo (P < .01). Bacon treatments did not differ for APC (P = .089), TBARS (P = .325), a* values (P = .102), off odor (P = .773), oxidized flavor (P = .407), sour flavor (P = .380), or percentage acceptability (P = .265). Bacon aged 60 d had the highest APC (P < .01). Bacon treated with STPP had lower L* values than other treatments (P < .01). Off odor was highest in bacon aged 4 mo to 6 mo (P < .01). Control bacon was saltier than other treatments (P = .03). Both oxidized and sour flavors increased with time, whereas percentage acceptability decreased as time increased (P < .01). No difference was detected for cook loss (P = .656), cook yield (P = .607), L* or a* during display (P ≥ .194), or treatment a* (P = .271). Control hotdogs had the highest APC (P < .01), and APC generally increased from 30 d to 150 d of aging. Control hotdogs had higher (P < .01) TBARS values than other treatments. Brifisol 450 had lower (P < .01) L* values than other treatments. Hotdog aroma (P = .04) was lower in 6-mo aged samples compared to aging months 1 through 4. Age and treatment affected off flavor, with 180 d resulting in the most off flavor (P = .01). Control hotdogs had more (P < .01) off flavor than Brifisol 450 and STPP. Brifisol 450 hotdogs were saltier (P = .02) than control. Percentage of acceptability was higher (P = .03) in months 1 to 4 compared to months 5 and 6 and in STPP and Brifisol 450 compared to control.

Conclusion: Phosphate treatments had little effect on APC or TBARS of ham samples. Inclusion of phosphates in ham improved sensory qualities of ham including hotdog aroma, juiciness, flavor and overall acceptability. Bacon APC, TBARS, and sensory did not improve with phosphate inclusion. Phosphate treatments reduced off flavors and had improved APC compared to control in hotdog samples. Percentage hotdog sensory acceptability decreased after 4 mo of storage, and phosphate treatments rated higher for acceptability than control.

Funding Source: Research funded by ICL Group of St. Louis, MO 63141, USA.

Keywords: pork, shelf life, sensory, oxidation, yield.

46 Carcass Weight Influences Chilling Rate, Metabolic Response, and Meat Quality

Grace C. Johnson^1,*, Mariane Beline², Leila G. Venzor¹, Kara A. Reynolds¹, Gary A. Sullivan¹, David E. Gerrard², and Jordan C. Wicks¹, ¹University of Nebraska–Lincoln, Lincoln, NE 68588, USA, ²Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA *gjohnson52@huskers.unl.edu

Introduction/Objectives: Over the past decade, beef carcass size has increased. Curiously, and at the same time, atypical dark-cutting (ATDC) beef has emerged as a notable quality defect in the beef industry. Unlike traditional dark, firm, and dry beef, which lacks sufficient glycogen for pH decline, ATDC beef has ample glycogen yet still exhibits a slightly elevated ultimate pH and results in darker lean. While the metabolic state of tissue of ATDC beef is known, the exact cause remains unclear. Previous literature suggests that lighter weight carcasses may be more prone ATDC, possibly as a result of faster chilling rates. However, this has yet to be proven definitively. Therefore, this study aimed to compare heavy- (HW) and light-weight (LW) carcass cooling rates to assess their response to standard harvesting and chilling practices, providing insight into the factors contributing to ATDC beef.

Materials and Methods: Forty-four and a half carcasses were randomly selected from contemporaneous commercial crossbred steers of similar physiologic maturity that were harvested under inspection at the University of Nebraska–Lincoln Loeffel Meat Laboratory. Carcass sides were allocated to a classification of either HW (n = 22; hot-carcass weight [HCW] = 231.41 ± 2.1 kg) or LW (n = 22; HCW = 181.08 ± 2.1 kg). Carcasses were subjected to similar standard harvesting procedures and temperatures and were continuously monitored using probes inserted approximately 10 cm into the longissimus lumborum (LL) between the 12th and 13th rib. Carcasses sides entered a conventional chilling cooler (2 ± 1°C) at approximately 60 min postmortem. Additionally, tissue from the LL was excised immediately following exsanguination (0 min) as well as at 3 h, 6 h, 12 h, and 24 h postmortem. Samples were diced, snap frozen in liquid nitrogen, and stored at −80°C until analyses. Muscle pH and metabolite levels of glycogen, glucose, and glucose 6-phosphate were analyzed to assess the metabolic changes of the muscle postmortem. Following a 30-h chilling period (2 ± 1°C), carcasses were ribbed between the 12th and 13th ribs for carcass evaluation and carcass maturity, and marbling scores were used to determine carcass quality grade. Objective color was also evaluated following a 1-h bloom time. Using a Minolta CR-400 colorimeter (Ramsey, NJ), triplicate color measurements were taken across the LL, and averaged color values were expressed as L* (lightness), a* (redness), and b* (yellowness). Finally, two 2.54-cm thick steaks were collected from the LL and stored at −20°C until shear force analysis. Data were analyzed as a completely randomized design using SAS software (SAS 9.4, SAS Institute Inc, Cary, NC). Carcass data, color, and shear force were analyzed using the MIXED procedure, considering the fixed effect of carcass weight (HW vs. LW) and the harvest day as random effect. Temperature, pH, and metabolites were analyzed as repeated measures considering the treatment, time, and their interactions as fixed effects and the harvest day as random effect. Covariance structures were tested for each characteristic, and the best fit was used. Differences were considered statistically significant when P ≤ .05 unless otherwise noted.

Results: Carcass data indicated that HW and LW carcasses differ in carcass composition. Specifically, HW carcasses had increased HCW (P < .001), ribeye area (P < .001), 12th rib fat thickness (P < .001), and percentage kidney, pelvic, and heart fat (P < .001). Subsequently, yield grade was higher (P < .001) in HW compared to LW carcasses as was marbling score (P < .001). Moreover, cooling rates of LW and HW carcasses differed with LW carcasses (P < .01) chilling at a faster rate than HW carcasses, specifically from 6 h to 24 h postmortem. Even so, all carcasses reached similar temperatures at 30 h postmortem when carcass and objective color were evaluated. The rate of pH decline was not different at 0 h, 3 h, 6 h, or 24 h postmortem. However, LW carcasses had an elevated (P < .05) pH at 12 h compared to that of HW carcasses. Although there was no interaction between weight and time postmortem, both glycogen (6 h, P < .05) and glucose 6-phosphate (6 h and 24 h, P < .01 and P < .05. respectively) were elevated in LW carcasses. Still, glucose was not different between treatments. Finally, our data show LW carcasses produced darker (L*, P < .05) and less red (a*, P < .001) lean than that of HW carcasses and resulted in less tender steaks at 1 d postmortem (P < .01) as indicated by Warner-Bratzler shear force values. There was also a trend for LW carcasses to produce a less tender steaks following a 14-d aging period (P = .08).

Conclusion: These data suggest that carcass weight alters chilling rate and changes meat quality traits through changing carbohydrate metabolism in muscle postmortem and support our hypothesis that LW carcasses, due to their faster chilling rate and metabolic differences, may be more susceptible to ATDC beef characteristics (darker, tougher). Still, the exact mechanisms remain unclear, and more work is needed to better understand the metabolic state of muscle in LW carcasses and its response to advanced chilling systems before recommendations can be made to commercial abattoirs.

Keywords: atypical dark cutting, carcass weight, carcass chilling, color, postmortem metabolism.

47 Predicting the Shelf Life of Ground Beef Based on the Initial Microbial Community Profile

Isabella G. Gafanha^* and Aeriel D. Belk, Auburn University, Auburn, AL 36849, USA *igg0009@auburn.edu

Introduction/Objectives: Food waste is a growing global issue that impacts consumers, producers, and environmental sustainability. The production of high-quality food products in the United States may alleviate this; however, many of those products that are produced tend to be discarded before they can be consumed. A primary reason for this elevated food waste at the consumer and retail level is the use of overly conservative sell-by and use-by dates on packages. Consumers believe that these dates are definitive markers of safety of the product and will discard according to those dates. Therefore, it is important that these dates accurately express the product’s shelf life, so it is not discarded prematurely. Meat spoilage is driven by numerous factors but primarily by microbial activity. The objective of this research project was to monitor the changes in microbial community structures over a 14-d shelf life to better predict and understand microbial succession patterns during spoilage.

Materials and Methods: Throughout the 14-d sampling, data were collected through colorimeter testing, lipid oxidation testing, microbial aerobic plate counts, and meat component analysis. Ground beef samples (80:20 lean-to-fat ratio) weighed out to 225-g tray overwrapped and randomly assigned pull dates and sample numbers. They went into simulated retail storage in an LED-lit, 3-tier display open-curtain retail case (Model TOM-60DX-BN, Turbo Air Inc., Long Beach, CA). To best simulate retail storage, the curtain was closed at night and open during the day. Instrumental color analysis was measured with the HunterLab MiniScan EZ colorimeter, Model 45/0 LAV (Hunter Associates Laboratory Inc., Reston, WV), following the American Meat Science Association Meat Color Measurement Guidelines, and the values were determined from the average of 3 readers per ground beef sample. The compositional analysis was conducted using a near-infrared with AOAC (2007.4) approved spectrophotometer (FoodScanTM, FOSS Analytical A/S, Hilleroed, Denmark), and data processing was determined using ISIscanTM software to analyze the nutrient content in the meat. Microbial aerobic plate counts (APC) were completed each day to determine the rate of spoilage. A series of serial dilutions were done to demonstrate coliforms present. The plate counts demonstrated when the samples reached spoilage, indicated by 107 CFU/g. The development of oxidative rancidity and lipid oxidation in the samples was evaluated throughout the sampling period using 2-thiobarbituric acid reactive substances (TBARS). The overall microbial communities were assessed using 16S amplicon gene sequencing methods. DNA extraction was performed using the Illumina miSeq platform. A 2-step centrifugation pre-extraction treatment was completed on the samples prior to DNA isolation. Samples were diluted in peptone buffer and hand-massaged for 30 s. Supernatant from the homogenization was then placed in a 15-mL conical tube and centrifuged at 200 rcf for 3 min. Following the first centrifugation, 10 mL of the supernatant was removed and centrifuged again at 10,000 rcf for 3 min. DNA was extracted using Zymo Research Quick-DNA^™ Miniprep Kits. DNA quantification was done with an Invitrogen Qubit^™ Flex Fluorometer. A statistical assessment of microbial taxonomies was used to see how they change over time.

Results: The spoilage period for this study was identified using the aerobic bacterial populations. Microbes were removed from the product’s surface and then serially diluted and plated on aerobic count plates. The plates were then incubated at 35°C to obtain counts of aerobic organisms. The quality analysis results show that the product was microbiologically spoiled at day 6 of the experimental period, with spoilage being defined as a microbial APC of 107 Log CFU/g. Further evidence of spoilage included instrumental color showing how the shelf life and microbial activity cause the color to change over time. The color results demonstrate statistical significance by day among L*, a*, and b* (P < .05). The results show a decrease in lightness and redness values, meaning the meat was becoming darker and less red as spoilage progressed. Additionally, the redness values decreased throughout spoilage as oxidation occurred. Lipid oxidation was measured through the quantification of malonaldehyde within the ground beef throughout the shelf life. The results of lipid oxidation demonstrate a relationship with the other factors affecting spoilage, as day 6 of the experimental period began to show rancidity (P < .05). As analysis continued, the microbial communities involved became less diverse, as certain organisms outcompeted the others in the environment. Prior to spoilage, the higher concentration of communities, such as Rhodobacteraceae and Enterobacterales, were present due to the initial microbiome of ground beef. As the shelf life progressed, the most dominant increased in Pseodomonadaceae, which is a known leading spoilage organism. There were also higher populations of Carnobacteriaceae, Listeriaceae, Streptococcaceae, Lactobacillaceae, and Yersiniaceae throughout the shelf life. Although many organisms were present on the day of grinding, the study demonstrated a decrease in microbial diversity throughout the experiment, as the organisms outcompeted each other in this time, fighting for limited resources.

Conclusion: The overall goal of this study was to observe the microbial spoilage patterns associated with ground beef to better predict when the product is truly microbially spoiled. We were able to conclude, with the accumulation of quality data and microbiome analysis, the product is microbially spoiled at day 6 of the experimental period. The results of this experiment allow for a better understanding of ground beef spoilage and can help with limiting excess food waste at the retail and consumer levels. Findings from this study are similar to previous results seen in literature for changes in microbial communities throughout spoilage; however, further analysis still needs to be done to answer the question relating to predicting the ground beef spoilage based on the initial microbial community profile. This pattern will help with predicting the rate of product spoilage, ultimately helping to decrease global food waste.

Funding Source: Alabama Beef Checkoff.

Keywords: microbiology, microbiome, beef, shelf life, spoilage.

48 Evaluation of GNS LQ30 as a Bacteriostatic Treatment to Extend Shelf Life in Ground Beef

Rafael Martinez^*, Markus Miller, and Mindy Brashears, Texas Tech University International Center for Food Industry Excellence, Lubbock, TX 79409, USA *rafaelma@ttu.edu

Introduction/Objectives: This study evaluated the bacteriostatic efficacy of GNS LQ30 in extending the microbial shelf life of ground beef. The primary objective was to assess reductions in total aerobic plate counts (AC) and lactic acid bacteria (LAB) populations in ground beef treated with GNS LQ30 compared to an untreated control over a 28-d refrigerated storage period.

Materials and Methods: Two treatments were evaluated. Fresh beef trimmings were either untreated (control) or treated with a 5% solution of GNS LQ30 applied before coarse grind and packed into 5-lb chubs. Chubs were stored at 4°C or lower for 0 d, 21 d, and 28 d. On the different stored days, chubs were fine ground, packaged into 1-lb trays, and wrapped with polyvinyl chloride film for retail display. At the retail display, enumeration of AC and LAB were conducted at 0 h, 24 h, 48 h, 72 h, and 96 h for each day the chubs were stored. Microbial indicator analysis was performed by collecting 10-g samples (n = 9) at each timepoint the trays were displayed. Consecutively, 90 mL of buffered peptone water was added and stomached at 230 rpm before enumeration using TEMPO^® Biomerieux over the 96-h display period. A t-test (P < .05) was performed to determine significant differences between treatments at each time point with R software version 4.4.3.

Results: On day 0, AC counts in control samples were significantly higher (1.68 ± 0.08 Log CFU/g) than in GNS LQ30-treated trim (0.60 ± 0.10 Log CFU/g; P < .05). This trend persisted throughout the 96-h display period, with treated samples maintaining significantly lower microbial loads (P < .05). By 96 h, control samples reached 2.10 plus or minus 0.15 Log CFU/g, while treated samples remained at 0.98 plus or minus 0.09 Log CFU/g. For chubs stored 21 d and 28 d, GNS LQ30-treated samples exhibited consistently lower AC counts at all time points compared to controls (P < .05), demonstrating its bacteriostatic effect. LAB counts were initially low in both treatments but increased after prolonged storage. At 21 d, LAB counts at 96 h were lower in GNS LQ30-treated samples (6.46 ± 0.07 Log CFU/g) than in controls (6.76 ± 0.09 Log CFU/g; P < .05). A similar trend was observed on chubs stored for 28 d.

Conclusion: The application of GNS LQ30 significantly reduced AC and LAB initially upon treatment, and microbial growth across all time points was lower, thus resulting in an extension of microbial shelf life in ground beef. These findings suggest the natural product may be a viable intervention for enhancing the microbial quality of retail ground beef.

Figure 1.

Aerobic plate counts by treatment at each timepoint.

Figure 2.

Lactic acid bacteria counts by treatment at each timepoint.

Funding Source: Texas Tech University International Center for Food Industry Excellence, Texas Tech University, Prosur Inc.

Keywords: beef trimming, indicators, quality.

49 Wet Aging Influences Color Stability of Lamb Longissimus Lumborum Muscle

Oluwatobi M. Ogunsola^1,*, Ana Paula Salim¹, Gregg Rentfrow¹, Donald G. Ely¹, Brittany E. Davis², and Surendranath P. Suman¹, ¹Department of Animal and Food Sciences, University of Kentucky, Lexington, KY 40506, USA, ²Forage Animal Production Research Unit, US Department of Agriculture, Agricultural Research Service, Lexington, KY 40546, USA *oluwatobiogunsola@uky.edu

Introduction/Objectives: Lamb color influences consumer purchase decisions, whereas tenderness is associated with eating satisfaction. Muscles in a lamb carcass exhibit biochemical variations that impact quality. Wet aging of lamb enhances tenderness, though it can adversely affect color. However, the influence of wet aging on fresh lamb color is not completely understood. Therefore, we investigated the effect of wet aging (for 0, 10, 20, and 30 d) on the color stability of lamb Longissimus lumborum (LL) muscles during refrigerated storage.

Materials and Methods: The LL muscles were excised (24 h postmortem) from both sides of 12 (n = 12) lamb carcasses obtained from the US Department of Agriculture-inspected meat laboratory of the University of Kentucky. The muscles were divided into 2 equal-length sections. The muscle sections were vacuum packaged and randomly assigned to either 0 d (A0), 10 d (A10), 20 d (A20), or 30 d (A30) d of wet aging at 2°C. At the end of each wet-aging period, the muscle sections were removed from the vacuum package and were fabricated into 2.5-cm thick chops. The chops were packaged in aerobic conditions and randomly assigned to 0 d, 3 d, 6 d, and 9 d of storage (2°C) in the darkness. Myoglobin concentration, surface redness (a*), color stability (R630/580), and lipid oxidation (thiobarbituric acid reactive substances [TBARS]) were assessed on each day of storage. A split plot with a completely randomized block design was utilized. The LL muscle section served as a whole plot, and the subplot consisted of chops. The analysis of variance was determined using the MIXED procedure of SAS, and the differences among means were detected using the least significant difference at a 5% level.

Results: The chops from nonaged (A0) LL muscles exhibited greater (P < .05) myoglobin concentration than their aged counterparts on day 0 of storage, whereas no differences (P > .05) among nonaged and aged chops were observed on days 3, 6, and 9 of storage. A decrease (P < .05) in myoglobin concentration during storage was observed in A0 and A10 chops, whereas A20 and A30 counterparts exhibited stable (P > .05) values during storage. The LL chops from A10 exhibited a greater (P < .05) a* value than A0 and A30 on days 3, 6, and 9 of storage. Storage influenced (P < .05) a* value only in A10. Initially the a* value increased from day 0 to 3 and then remained stable (P > .05) until day 9 of storage. The LL chops from A10 exhibited greater (P < .05) R630/580 than A20 and A30 on day 0 of storage, whereas, on days 3 and 6 of storage, A10 exhibited greater (P < .05) R630/580 than A0 and A30 chops. At the end of 9 d of storage, A10 chops exhibited greater color stability than their counterparts from A0, A20, and A30. Nonetheless, there was a decrease (P < .05) in R630/580 in all treatments during 9 d of storage. Overall, A30 chops exhibited greater (P < .05) TBARS than the others on days 0, 3, 6, and 9. Additionally, all chops exhibited an increase in TBARS from day 0 to 9 of storage.

Conclusion: These findings suggested that wet aging influenced the color stability of lamb LL muscle. Lamb chops aged for 10 d exhibited enhanced surface redness and color stability. Wet aging for 10 d could be used as a practical processing strategy in the lamb industry to improve the color stability.

Funding Source: US Department of Agriculture, Agricultural Research Service (ARS), National Program 101, Food Animal Production (ARS Project 5042-32630-004-00D).

Keywords: color stability, lamb color, wet aging.

50 Differential Effect of Freezing and Thawing on the Color Stability of Bison Strip Steaks and Ground Bison

Ian Byington^1,*, Garrett Weldy¹, Christina Bakker¹, Judson Grubbs¹, Keith Underwood¹, Lydia O’Sullivan², Surendranath Suman³, and Amanda Blair¹, ¹Department of Animal Science, South Dakota State University, Brookings, SD 57007, USA, ²Department of Animal and Equine Science, Murray State University, Murray, KY 42071, USA, ³Department of Animal and Food Sciences, University of Kentucky, Lexington, KY 40506, USA *ian.byington@jacks.sdstate.edu

Introduction/Objectives: Meat color is a major factor that drives consumers’ purchasing decisions. When color deviates from consumers’ expectations, willingness to pay decreases, resulting in a reduction in profit and an increase in food waste. Storage conditions prior to consumption, such as freezing and thawing, can significantly impact the color stability of meat. In contrast to other animal protein sources, bison is often marketed frozen. In 2023, approximately 635,000 kg of frozen bison were sold in the United States. Freezing allows meat processors and distributors to sustain a consistent supply of bison products; however, storage interventions that alter the initial appearance and color stability could impact willingness to pay and contribute to food waste. Therefore, the objective of this study is to determine the effects of freezing and thawing on the color stability of bison striploin steaks and ground bison.

Materials and Methods: A single lot of bison (n = 35 carcasses) was selected from a commercial packing facility for the study. Carcasses were evaluated for instrumental color (L*, a*, and b*) of the ribeye. A subsample of carcasses (n = 20 carcasses closest to the lot’s average a*) was selected for further analysis. Striploins were collected from 1 side of each subsampled carcass and fabricated into steaks (2.5-cm thick). Bison trim was also collected from the subsampled carcasses. Steaks and trim were transported to the South Dakota State University Meat Laboratory for treatment allocation and analysis. Upon arrival, trim was divided into 6 batches (4.5 kg/batch) and twice ground through a 5-mm plate. Ground bison (0.45 kg/package) and steaks were packaged in vacuum-sealed bags. Ground bison packages (n = 6 packages/batch) from each batch and steaks (n = 6 steaks per striploin) from each striploin were assigned to 1 of 2 treatments: treatment 1 (fresh), in which samples were stored in boxes at 4°C for 11 d before a simulated retail display, or treatment 2 (thawed), in which samples were frozen immediately, stored in boxes at −20°C for 41 d, then thawed at 4°C for 24 h before a simulated retail display. During the display period, fresh samples were evaluated for 31 d, and thawed samples were evaluated for 10 d after thawing. Objective color was evaluated using a handheld colorimeter every 3 d of the display period. Subjective color was evaluated by trained panelists every 3 d of the display period. Products were evaluated for color (1 = moderately light purple red, 6 = extremely dark purple red) and discoloration score (1 = no discoloration [0%], 6 = extensive discoloration [81–100%]). ΔE was calculated as a measurement of discoloration. Objective and subjective color data were analyzed as repeated measures with treatment, day, and their interaction as fixed effects using the MIXED procedure of SAS. ΔE was analyzed using the GLIMMIX procedure of SAS with the fixed effect of treatment. Striploin served as the experimental unit for steak data, and batch was the experimental unit for ground bison data.

Results: A treatment × day interaction (P < .0001) was observed for all objective and subjective color data on bison steaks. Initially, thawed steaks were redder (P < .05) than fresh steaks and had less objective and subjective discoloration. The a* values of fresh steaks did not differ (P > .05) from display day 0 to 30, while thawed steaks decreased (P < .05) in redness from display day 0 to 9. Subjective discoloration scores increased (P < .05) from the beginning to the end of the display period for both treatments; however, thawed steaks had a significantly higher (P < .05) subjective discoloration score on days 6 and 9 of display compared to fresh steaks. By day 6, 80% of thawed steaks had a subjective discoloration score of 6, leading to the early termination of the retail display at day 9 for all thawed samples. Steak subjective color scores increased (P < .05) from the beginning to the end of the display period for both treatments. Fresh steaks had a smaller (P < .05) ΔE than thawed steaks, indicating less color change from the beginning to the end of the color display. A day effect (P < .0001) was observed for objective color measurements of ground bison, while a treatment × day interaction (P < .0001) was observed for subjective color data. The a* of ground samples decreased (P < .05) from day 0 to the end of the display period. Storage treatment did not influence (P > .05) discoloration scores from day 0 to day 3 of the display period. However, on day 6 and day 9, the thawed grind had greater (P < .05) subjective discoloration scores compared to fresh ground bison. The subjective color scores of ground bison increased (P < .05) from the beginning to the end of the display period for both treatments. Thawed ground bison had a smaller (P < .05) ΔE than fresh for the whole display period (fresh: day 0–30, thawed: day 0–9). However, when both treatments for grind samples were evaluated for the same length of time (day 0 to 9), there were no differences (P > .05) between treatments for ΔE. The difference observed for the entire display period could be attributed to the extended amount of time the fresh treatment was on display when compared to the thawed treatment.

Conclusion: These data indicate that the color stability of bison strip steaks is more susceptible to the effects of freezing and thawing than ground bison. Overall, freezing and thawing produced steaks with an increased rate of discoloration, while the effects of freezing and thawing had a limited impact on the color stability of ground product when evaluated for the same length of time. Thawed steaks had less discoloration than fresh steaks on day 0; however, fresh steaks maintained their color during the entirety of the panel. The bison market is expected to grow 6.5% annually over the next 7 y, and there could be opportunities to grow market share if desirable color can be maintained after thawing. Future research is warranted to determine optimal freezing and thawing conditions for bison products to ensure color stability and consumer satisfaction.

Funding Source: This research was supported by state and federal funds appropriated to South Dakota State University, including support from the South Dakota State University Agriculture Experiment Station, US Department of Agriculture National Institute of Food and Agriculture through the Hatch Act (accession #7008365), and by the Center of Excellence for Bison Studies.

Keywords: bison, color, freezing, thawing, quality.

51 Characterizing Muscle-Specific Pork Quality of the Semitendinosus, Gluteus Medius, Psoas Major, Longissimus Thoracis, and Triceps Brachii

Yifei Wang^*, Rebecca Brown, Milena Conte, Lyda G. Garcia, and Benjamin M. Bohrer, Department of Animal Sciences, The Ohio State University, Columbus, OH 43210, USA *wang.10408@osu.edu

Introduction/Objectives: Most research on fresh pork quality has predominantly focused on the pork loin (Longissimus thoracis et lumborum) muscle. However, variation in pork quality exists across muscles throughout the carcass due to differences in biochemical composition and postmortem metabolism. Studies have suggested the quality traits of pork loin were not representative of the entire carcass, yet research beyond the loin muscle remains limited. Understanding muscle-specific pork quality and eating experience could optimize fresh muscle cut handling strategies (aging and cooking), enhance consistency of pork quality, and expand fresh pork offerings. Therefore, the objectives were to characterize the rate of pH and temperature decline, pork quality attributes, and proteolytic changes during postmortem aging of 5 muscles, including the semitendinosus (ST), Gluteus medius (GM), Psoas major (PM), Longissimus thoracis (LT), and Triceps brachii (TB), as well as to evaluate the influence of endpoint cooking temperature on eating experience for each muscle cut.

Materials and Methods: Fifteen barrows (hot-carcass weight = 93.2 ± 3.0 kg; offspring of maternal-line genetics) were slaughtered using single-file electrical stunning. The pH and temperature of ST, GM, PM, LT, and TB were measured at 1 h, 3 h, 6 h, 9 h, 12 h, and 24 h postmortem during the conventional chilling period and analyzed using repeated measures. Instrumental Commission Internationale de l’Eclairage color (L*, a*, b*), drip loss, and intramuscular fat content of each muscle were evaluated using a Minolta CM-700d colorimeter, the EZ cup method, and Soxhlet extraction, respectively. These evaluations were conducted following carcass fabrication at 24 h postmortem and analyzed as a randomized complete block design, with muscle as the fixed effect and slaughter day as the random effect. Warner-Bratzler shear force (WBSF) was determined using a TA-XT Plus texture analyzer following postmortem aging for 1 d, 3 d, or 10 d and endpoint cooking temperatures of either 63°C or 71°C using sous-vide cooking. Data were analyzed using a split–split-plot design, with muscle as whole-plot factor, aging day as the subplot factor, and cooking temperature as the sub-sub plot factor. Postmortem proteolysis was evaluated by conducting Western blots for calpain-1 autolysis, desmin degradation, and troponin-T degradation. Calpain-1 autolysis was evaluated at 1 d postmortem and analyzed as a randomized complete block design, with muscle as the fixed effect and slaughter day as the random effect. Desmin and troponin-T degradation were measured at 1 d or 10 d postmortem and analyzed as a split-plot design, with muscle as whole-plot factor and aging day as the subplot factor. Trained sensory evaluation was performed on the 5 muscle cuts following 10 d of postmortem aging and endpoint cooking temperatures of either 63°C or 71°C using sous-vide cooking. Tenderness, juiciness, chewiness, and pork flavor were evaluated by trained panelists on 15-cm continuous-line scales anchored at 0 cm, 7.5 cm, and 15 cm. Sensory data were analyzed as an incomplete block design, with fixed effects of muscle cut, cooking temperature, and their interaction and random effects of panel session, panelist, pork carcass, and their interactions. All statistical analyses were performed using PROC GLIMMIX of SAS v9.4.

Results: The main effect of muscle was significant (P < .01) for rate of pH and temperature decline, lightness (instrumental L*), redness (instrumental a*), drip loss, and intramuscular fat content. The LT had faster (P < .05) rates of pH decline from 1 h to 3 h postmortem compared with the TB, while the ST and GM were at intermediate levels, and the PM was much slower than all other muscles. The LT and PM had faster (P < .05) rates of temperature decline from 1 h to 3 h postmortem compared with the TB and GM, while the ST was at intermediate levels. The LT had the greatest (P < .05) drip loss compared with all other muscles. A muscle and cooking temperature interaction (P < .01) was observed for WBSF, sensory tenderness, and sensory juiciness. Muscle-specific differences existed when observing the magnitude of change between the 2 endpoint cooking temperatures, which can be used to explain how forgiving each individual muscle cut may be to endpoint cooking temperatures above recommended levels of 63°C. Reducing endpoint cooking temperature resulted in the greatest change in WBSF for the GM and the greatest change for sensory juiciness and sensory pork flavor for the LT. Regardless of cooking temperature, the GM had the greatest WBSF, while the PM had the lowest WBSF. Moreover, the PM and the ST had the most favorable sensory tenderness, sensory juiciness, and sensory pork flavor scores. When comparing the sensory scores with the midpoint (7.5) of the 15-cm sensory scale, all muscle cuts had mean ratings on the more tender and more juicy side of the sensory scale (scores > 7.5) at 63°C, while all muscle cuts had mean ratings on the tougher and drier side of the sensory scale (scores ≤ 7.5) at 71°C. Additionally, an interaction between aging days and endpoint cooking temperature influenced (P = .02) WBSF, with the reduction in WBSF from 71°C to 63°C being more pronounced at 1 d and 3 d of aging compared with 10 d. Furthermore, postmortem proteolysis varied among muscles, with LT and GM demonstrating greater (P < .05) calpain-1 autolysis at 1 d postmortem compared to other muscles. Additionally, at both 1 d and 10 d postmortem, the GM exhibited the greatest (P < .05) desmin degradation, while the LT showed the greatest (P < .05) troponin-T degradation.

Conclusion: The results of the current study identified muscle-specific variations in the rate of pH decline, instrumental color, tenderness, water-holding capacity, extent of proteolysis, and eating experience of 5 pork muscles. The LT exhibited the fastest rate of pH decline, the greatest drip loss, and was the least forgiving at greater cooking temperatures, exhibiting the most significant reductions in juiciness scores when cooked to 71°C rather than 63°C. The variation in pork quality traits and postmortem proteolysis were likely influenced by muscle fiber type but should not be explained solely by variations in muscle fiber type distribution. Instead, these differences were likely influenced by other muscle-to-muscle variations in live muscle function (i.e., support vs. locomotion) and postmortem metabolism. Therefore, consideration should be given to the individual muscle cuts of interest when evaluating pork quality.

Funding Source: This research was funded by the Ohio State University College of Food, Agricultural, and Environmental Sciences internal grants program.

Keywords: muscle profile, muscle biochemistry.

52 Second Dose to Marketing Time Interval Influences Fat Quality of Market Gilts Managed With Immunologic Suppression of Ovarian Function

Benjamin M. Bohrer^1,*, Manuel Juárez², Blaine Hansen³, Jose Landero⁴, Malachy Young⁴, and Leanne Van DeWeyer⁵, ¹Department of Animal Sciences, The Ohio State University, Columbus, OH 43210, USA, ²Agriculture and Agri-Food Canada, Lacombe, AB T4L 1W1, Canada, ³BCH Consulting LLC, Atlantic, IA 50022, USA, ⁴Gowans Feed Consulting, Wainwright, AB T9W 1L2, Canada, ⁵Zoetis Canada, Kirkland, QC H9H 4M7, Canada *bohrer.13@osu.edu

Introduction/Objectives: Temporary immunologic suppression of ovarian function and estrus is achieved in market gilts with Improvest (Zoetis Inc.). The product requires 2 sequential subcutaneous injections (i.e., doses) administered at least 4 wk apart, with full suppression of ovarian function demonstrated 4 wk to 10 wk after the second dose. Recent research has shown the performance changes and financial importance of closely monitoring the duration between the second dose and slaughter (i.e., time interval postsecond dose), and current recommendations for optimal performance benefits are to market gilts at a weighted average of 40 d postsecond dose, with all gilts being marketed prior to 49 d postsecond dose. The objective was to determine the effect of time interval postsecond dose on fat quality of market gilts managed with immunologic suppression of ovarian function.

Materials and Methods: The live animal portion of the study consisted of 1,008 market gilts (PIC 800 sire × PIC Camborough F1 sows; Genus PIC) housed in 48 pens within the same barn with 21 pigs/pen. Pigs were randomly allocated to 8 treatments at the start of the grow-finish period (average starting weight of 30 kg). A total of 160 market gilts (3 or 4 per pen) were used for this study and were the first pigs marketed from pens. Treatments were 1 treatment of nonimmunized gilts (CON) and 7 treatments of immunized gilts (Improvest, Zoetis Inc.), varying second dose to marketing time interval. The 7 treatments for the immunized gilts were intervals between the second dose and marketing of 7 d (Improvest Strategy 1), 14 d (Improvest Strategy 2), 21 d (Improvest Strategy 3), 28 d (Improvest Strategy 4), 35 d (Improvest Strategy 5), 42 d (Improvest Strategy 6), or 49 d (Improvest Strategy 7). Timing of doses was altered so that the interval between dose 1 and dose 2 was 35 d for all treatments, and all treatments were marketed on a fixed time basis. Pigs (N = 160) were slaughtered in a provincially inspected facility using group CO₂ stunning and conventional chilling. Loins were evaluated for pH, subjective color, instrumental color, subjective marbling, and subjective firmness. Bellies were evaluated for dimensions (thickness, width, and length), skin tension, and belly bend angle. Subcutaneous fat samples were collected from the posterior dorsal edge of the belly (i.e., under the flank muscle) and evaluated for fatty acid profile. Data were analyzed with the MIXED procedure of SAS (v9.4; SAS Inst. Inc.), with pen serving as the experimental unit. Treatment served as the fixed effect, while block (weight at the start of the grow-finish period) served as a random effect in the statistical model. Single degree of freedom contrast statements were used to test the difference between the CON treatment and the 7 treatments of immunized gilts as well as the linear and quadratic effects among the 7 treatments of immunized gilts. Differences between treatments were considered significant at a P value less than or equal to .05.

Results: Hot-carcass weight (HCW), dressing percentage, and last rib backfat thickness were neither different (P ≥ .20) among treatments, nor were there linear or quadratic effects (P ≥ .25) among the 7 treatments of immunized gilts. This was surprising, as previous research has supported a 3% improvement in HCW (95% CI, 2.5–3.5%) and 2.8-mm greater backfat thickness for immunized gilts compared with nonimmunized gilts. There were limited differences (P > .05) observed for loin quality parameters. There were limited treatment differences for belly dimensions (i.e., thickness measured at the shoulder end, thickness of the soft tissue layers measured at the latissimus dorsi location, thickness measured at the bend site, belly width, and belly length). The only significant treatment differences (P < .05) were for layer 1 thickness (first layer of lean) and layer 5 thickness (intermediate subcutaneous fat layer) at the bend site. Both of these values did not follow consistent linear trends, and the CON treatment was intermediate in value compared with the 7 treatments of immunized gilts. Additionally, there were limited instances of significant linear or quadratic trends among the 7 treatments of immunized gilts for belly dimensions. The lone linear effect (P < .01) was for layer 3 thickness (obliquus internus abdominis muscle) at the bend site, which decreased as time interval postsecond dose increased (i.e., from Improvest Strategy 1 to Improvest Strategy 7). There was a significant treatment effect (P = .02) and a significant linear effect (P = .01) for skin tension. Skin tension scores decreased as time interval postsecond dose increased. There was a significant treatment effect (P = .03) for belly bend angle. Gilts managed with Improvest Strategy 5, 6, and 7 had lower (P < .05) values for belly bend angle compared with the CON treatment. There were significant treatment effects (P < .05) for total saturated fatty acids (SFA) and iodine value (IV) and significant linear effects (P < .05) among the 7 treatments of immunized gilts for total SFA, total monounsaturated fatty acids (MUFA), total polyunsaturated fatty acids (PUFA), and IV. As time interval postsecond dose increased, the percentage of SFA increased, and the percentage of MUFA and PUFA decreased. This resulted in linear decrease in IV as time interval postsecond dose increased. Specifically, IV for gilts managed with Improvest Strategy 5 and 6 were 1.8 U and 2.0 U lower than nonimmunized gilts, respectively.

Conclusion: Loin quality was not different between nonimmunized gilts and gilts managed with immunologic suppression of ovarian function and estrus. Belly firmness and fatty acid profile can be improved when managing gilts with ovarian function and estrus, but improvements were not observed until 35 d following the second dose of Improvest, where IV, skin tension test, and belly bend angle all began to deviate from nonimmunized gilts.

Funding Source: Funding was provided by Zoetis Inc.

Keywords: anti-GnRF, estrus suppression, fat.

53 Influence of Spoilage Bacterial Load on Beef Striploin Color Stability During Retail Display

Allison C. Grande^*, Colton L. Smith, Ifigenia Geornaras, and Mahesh N. Nair, Department of Animal Sciences, Colorado State University, Fort Collins, CO 80521, USA *agrande@colostate.edu

Introduction/Objectives: The color and appearance of beef significantly influence consumer purchasing decisions, which, in turn, influences its retail shelf life. Recent studies suggest that 2.55% of beef produced in the United States is discarded due to discoloration, resulting in an annual economic loss of $3.7 billion for the beef industry. Previous studies have also indicated that spoilage bacteria can influence the color of beef and its shelf life. Specifically, differences in bacterial growth kinetics could play a role in the muscle-specific color stability of beef muscles. However, the impacts of different starting levels of spoilage bacteria present at the time of packaging and their growth on beef color during retail display are not clearly understood. Therefore, the objective of this study was to investigate the impact of different initial levels of spoilage bacteria on the shelf life (color and odor) of beef striploin steaks during retail display.

Materials and Methods: Eight side-paired US Department of Agriculture choice beef striploins (n = 8) were randomly selected and aged under vacuum (2°C, 14 d) in 2 separate trials (n = 4/trial). After aging, striploins were surface-decontaminated by immersion into boiling water (2 min), followed by aseptic removal of the heat-exposed surface and fabrication into 1-cm thick steaks. The steaks were placed on foam trays, and the upper surface was inoculated with a mixture of 6 beef spoilage bacteria (3 Pseudomonas spp. and 3 lactic acid bacteria [LAB]). The inoculation levels targeted were 2 Log CFU/cm², 4 Log CFU/cm², and 6 Log CFU/cm² (designated as low-INOC, medium-INOC, and high-INOC, respectively). Inoculated steaks were overwrapped with polyvinyl chloride film and placed into a multideck retail display case (0–3°C) for up to 9 d (the first day was designated as day 0). On each display day, lightness (L*), redness (a*), and yellowness (b*) were measured instrumentally, and trained visual panelists determined lean color and percentage discoloration on each steak’s surface. Additionally, a 4-cm by 4-cm area of the light-exposed surface of the steaks was excised and analyzed for aerobic plate counts (APC), LAB counts, and Pseudomonas spp. counts. After sampling steaks for microbial analysis, the remaining light-exposed surface was excised and placed into capped glass tubes and used for qualitative odor analysis. Using Qualtrics, panelists were asked to indicate if they considered the sample spoiled and whether they would consume or cook the product with that odor. The data for instrumental color, panelist color, and microbial counts were analyzed in a factorial model with inoculation level, display day, and their interaction as fixed effects, with trial as a block, and carcass as a random variable. Means were separated using analysis of variance with Kenward-Roger degrees of freedom adjustment, and data were separated with the emmeans package in R. Significance was set at a P value of less than .05. Results for the odor analysis were analyzed using a binomial logit model with the same model parameters as the factorial design, and data were reported as odds ratios.

Results: The mean initial (day 0) APC recovered from the low-INOC, medium-INOC, and high-INOC steaks were 1.6 Log CFU/cm², 3.5 Log CFU/cm², and 5.6 Log CFU/cm², respectively. The APC of all 3 treatments remained unchanged (P > .05) until day 5 (low-INOC, high-INOC) and day 6 (medium-INOC) of retail display. However, the APC increased (P < .05) by 2.6 Log CFU/cm² to 2.7 Log CFU/cm² (compared to day 0) by day 9 across all 3 INOC treatments. On the last day of retail display, the APC of steaks were 4.2 Log CFU/cm² (low-INOC), 6.2 Log CFU/cm² (medium-INOC), and 8.2 Log CFU/cm² (high-INOC). The Pseudomonas spp. counts followed a similar trend to that obtained for the APC, whereas the LAB counts increased at a slower rate compared to the 2 other bacterial count types. All 3 treatments had similar (P > .05) redness and yellowness on day 0 of the retail display. The redness was similar (P > .05) between the treatments until day 6, after which the high-INOC samples had lower (P < .05) redness compared to the other 2 treatments. By day 9, the low-INOC, medium-INOC, and high-INOC steaks had redness values of 24.47, 22.59, and 15.39, respectively, indicating that steak surface redness was influenced by the bacterial load. Similar to a*, yellowness for the high-INOC was lower (P < .05) compared to the other 2 treatments from day 7 through day 9 of the retail display. In agreement with the instrumental redness results, the panelist’s lean color scores and discoloration scores were higher (P < .05) for high-INOC on day 7 through day 9 compared to the other treatments. By day 9 of the retail display, the high-INOC steaks were 67% discolored as compared to 5.4% for the low-INOC and 9.5% for the medium-INOC samples. The odor panelists were more likely (P < .05) to consider a sample as spoiled with increased inoculation level and increasing retail display days. Specifically, the high-INOC steaks were 1.3 times more likely to be considered spoiled compared to the low-INOC samples, and day 9 samples were 24.8 times more likely to be considered spoiled compared to day 0 samples. Similarly, panelists were more likely (P < .05) to consume low-INOC steaks and with fewer days of retail display.

Conclusion: The results of the study indicated that regardless of the initial concentration of spoilage bacteria, bacterial levels increased by a similar magnitude on the beef striploin steaks by the end of the retail display. However, the color was influenced by bacterial levels once growth commenced, with the high-INOC treatment discoloring faster compared to the other treatments. These results suggest that the color of beef striploin steaks during retail display was influenced by the bacterial load (i.e., concentration) rather than the number of days of bacterial growth on the steaks.

Keywords: beef, bacteria, color, odor, spoilage.

54 Microbial and Biochemical Changes in Wet-Aged Beef Semimembranosus, Gluteus Medius, and Biceps Femoris Muscles

Maggie Holloway^1,*, Amelia Main², Sebastian Hernandez², Colton Smith¹, Gina Geornaras¹, Dale Woerner², Jerrad Legako², Travis O’Quinn³, Chris Kert⁴, Rhonda Miller⁴, Jessica Lancaster⁵, Maheah Nair¹, ¹Colorado State University, Fort Collins, CO 80523, USA, ²Texas Tech University, Lubbock, TX 79409, USA, ³Kansas State University, Manhattan, KS 66506, USA, ⁴Texas A&M University, College Station, TX 77843, USA, ⁵National Cattlemen’s Beef Association, Centennial, CO 80112, USA *maggie.holloway@colostate.edu

Introduction/Objectives: Postmortem wet aging is the most common aging method used in the meat industry to enhance tenderness, palatability, and overall consumer acceptance of beef. Previous industry surveys have indicated that the average aging time for beef is 25.9 d, while some beef cuts can get aged for up to 102 d. During postmortem aging, several microbiological and biochemical changes occur within the muscles. Most of the previous aging studies focused on the longissimus lumborum muscle. It has become more common to market single muscle cuts such as the semimembranosus (SM), gluteus medius (GM), and biceps femoris (BF). However, few studies have been conducted on microbial and biochemical changes in these muscles during aging. Therefore, the objective of this study was to determine the impact of aging on the microbial load, microbiome (16S ribosomal RNA gene sequencing and analysis), and desmin degradation of beef SM, GM, and BF.

Materials and Methods: Beef top rounds (SM) and sirloin top butts (N = 80) were collected at a commercial beef processing facility. These subprimals were wet aged for 14 d, 28 d, 35 d, 42 d, 49 d, 56 d, 63 d, or 70 d, and on each of these days, the BF and GM were separated from the top sirloin butt. Ten (n = 10) samples were analyzed from each muscle for each aging period. On each aging day, 2 separate 5-cm by 10-cm areas of the muscle were sampled using separate sponge samplers. Buffered peptone water was added to 1 set of sponge samples, followed by mechanical pummeling and analysis for total aerobic mesophilic microflora counts (AC) and lactic acid bacteria counts (LABC) using the TEMPO^® system. To the second set of sponges, phosphate-buffered saline (PBS) was added, and after mechanical pummeling, the liquid was collected and stored at −70°C for microbiome analysis. Additionally, on each aging day, the muscles were fabricated into 2.54-cm thick steaks, frozen in liquid nitrogen, powdered, and stored at −70°C for desmin degradation analysis. After extracting bacterial DNA from the PBS meat homogenate, microbiome library preparation was performed according to the Earth Microbiome Project (https://earthmicrobiome.org/), and an Illumina miSeq was used for sequencing. Downstream analysis was performed using the Qiime2 pipeline. Desmin degradation was analyzed using a Western blotting system. The protein concentration was measured using a detergent compatible protein assay and normalized with a Coomassie blue stain. The proteins were then separated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and transferred to a polyvinylidene fluoride membrane. Desmin was visualized using primary (polyclonal rabbit antidesmin) and secondary (goat antirabbit-HRP) antibodies. All data were analyzed using R, and significance was set at α equal to 0.05. After downstream analysis, microbiome analysis was performed using the phyloseq, vegan, and pairwiseAdonis packages, and samples were rarefied at 4800 sequences. The relative abundance, α diversity (with Shannon and Simpson diversity indices), and β diversity (Bray-Curtis and weighted UniFrac) were evaluated. The bacterial counts and desmin degradation were analyzed using the emmeans package and a linear mixed effects model. The 55 kDa intact band intensity was evaluated using iBright analysis software for desmin degradation.

Results: All 3 muscles had a low microbial load (<2 Log CFU/cm²) initially (day 14), which increased over time, as expected. In the SM, the AC did not increase (P > .05) after 28 d of aging, and LABC showed no substantial increases (P > .05) after 42 d. By day 70 of aging, the SM muscle had an AC of 5.6 Log CFU/cm² and LABC of 6.0 Log CFU/cm². In GM, the AC and LABC increased (P < .05) by 4.5 Log CFU/cm² and 3.8 Log CFU/cm², respectively, from day 14 to day 42 of aging. After 42 d, no significant differences (P > .05) in AC and LABC were obtained in the GM muscle. The AC at 70 d of aging for the GM was 6.4 Log CFU/cm², while the LABC was 6.0 Log CFU/cm². The AC of BF did not increase (P > .05) after 42 d, whereas the LABC did not increase (P > .05) after 35 d of aging. The bacterial load of the BF muscle at 70 d of aging was 6.1 Log CFU/cm² and 6.0 log CFU/cm² for AC and LABC, respectively. For all 3 muscles, the Leuconostoc bacterial genus had the greatest relative abundance, followed by Carnobacterium, when averaged over all 8 aging periods. Both α and β diversity of all the muscles decreased (P < .05) over time. The α diversity of the SM aged for 14 d was different (P < .05) from all other aging periods other than 35 d. The GM muscle had similar (P > .05) α diversity across all aging periods. However, the 14-d aging period was different (P < .05) from all other aging periods for β diversity indices. The α diversity of BF after 14 d of aging was similar (P > .05) to 28 d but differed (P < .05) from all other aging periods. On the other hand, β diversity after 14 d of aging was different (P < .05) from all other aging periods. Overall, there was an initial increase (P < .05) in desmin degradation with aging for all the muscles, but as aging time increased, there was no further increase in desmin degradation. Specifically, desmin did not degrade further after 35 d for the SM and BF and 49 d for GM.

Conclusion: Generally, for all 3 muscles, the microbial load and desmin degradation increased with aging, whereas microbial diversity decreased with aging. Aside from the initial 14-d aging period, the most abundant bacterial genera were lactic acid bacteria, which could potentially contribute to any souring or off flavors as beef ages. A higher degree of desmin degradation was observed with an increase in aging times for all the muscles, which could lead to increased tenderness. While there were some differences in microbial load, microbial diversity, and desmin degradation during early aging days, those disappeared as the aging time increased. Overall, these results suggest that a longer aging period for these muscles does not necessarily yield a higher-quality product.

Funding Source: Research coordinated by the National Cattlemen’s Beef Association, a contractor to the Beef Checkoff.

Keywords: beef, wet aging, microbiome, desmin, microbiology.

55 Nondestructive Prediction of Chicken Drip Metabolites Related to Spoilage

Hyun-Jun Kim^1,*, Jiwon Ryu², Gap-Don Kim¹, Jaehoon Baek¹, Ghiseok Kim², and Cheorun Jo², ¹Seoul National University, Pyeongchang-gun, Gangwon-do 25354, Republic of Korea, ²Seoul National University, Gwanak-gu, Seoul 08826, Republic of Korea *alponso92@snu.ac.kr

Introduction/Objectives: Chicken meat spoilage is a significant concern in the food industry, affecting product quality, safety, and shelf life. Conventional spoilage detection methods rely on microbiological and chemical analyses, which are often time consuming and destructive. Drip, the reddish liquid exuded from the surface of meat during storage, contains metabolites that undergo changes due to structural alterations caused by spoilage microorganisms and endogenous enzymes. Therefore, analyzing changes in drip metabolites can offer valuable insights into the condition of the meat. This study aimed to nondestructively monitor these metabolites using visible/near-infrared (Vis/NIR) spectroscopy combined with data augmentation techniques.

Materials and Methods: Chicken breast samples were vacuum packaged and stored at 4°C for 13 d. Drip samples were collected at different storage periods (days 5, 7, 11, and 13) and analyzed using both nuclear magnetic resonance (NMR) spectroscopy and Vis/NIR transmittance spectroscopy (600–1000 nm). Microbial composition changes were assessed using 16S ribosomal RNA (rRNA) sequencing to identify dominant bacterial species. Metabolites in the drip were quantified using 1-dimensional ¹H NMR spectroscopy. Spectral preprocessing was performed using standard normal variate, multiplicative scatter correction, range normalization, and maximum normalization. Data augmentation was applied using the offset method, which adds random Gaussian noise; the multivariate normal sampling (MVN) method, which resamples within a normal distribution; and the multivariate signal augmentation (EMSA) method, which generates new spectra by perturbing scatter correction coefficients. The prediction model used was the partial least-squares regression (PLSR) model. Model validation was conducted using leave-one-out cross-validation. The performance of the prediction model was evaluated using the coefficient of determination (R²), root mean squared error (RMSE), and residual predictive deviation (RPD).

Results: Chicken drip showed a significant increase in acetate, cadaverine, glutamate, hypoxanthine, methionine, putrescine, and tyramine over the storage period, whereas inosine monophosphate, tyrosine, and uridine monophosphate (UMP) significantly decreased (P < .05). According to 16S rRNA sequencing, Carnobacterium, Lactococcus, and Serratia became the predominant microorganisms in chicken meat after 13 d of vacuum-packaged storage. Transmittance spectra of chicken drip were measured and calibrated within the 600 nm to 1000 nm range. The raw spectra showed a gradual increase in transmittance from 600 nm to 850 nm, peaked at 850 nm, then decreased to a minimum between 900 nm and 950 nm before increasing again. Representative spoilage metabolites (acetate, cadaverine, putrescine, tyramine, tyrosine, and UMP), along with the preprocessed spectra, were used to train PLSR models. Each preprocessing method resulted in different prediction performances. Maximum normalization yielded the best results for acetate (R² = 0.56, RMSE = 0.15, RPD = 1.51), putrescine (R² = 0.65, RMSE = 0.10, RPD = 1.69), tyrosine (R² = 0.83, RMSE = 0.08, RPD = 2.42), and UMP (R² = 0.76, RMSE = 0.01, RPD = 2.05). Range normalization was most effective for cadaverine (R² = 0.77, RMSE = 0.14, RPD = 2.07), while no preprocessing provided the best prediction for tyramine (R² = 0.61, RMSE = 0.11, RPD = 1.61). When variable importance in projection (VIP)-based wavelength selection was applied, the R² values improved for all metabolites except UMP. Data augmentation methods (offset, MVN, and EMSA) also improved PLSR model performance for all 6 metabolites. Among them, EMSA led to the greatest improvements for acetate, cadaverine, putrescine, and tyramine, while MVN was most effective for tyrosine and UMP. Combining data augmentation with VIP-PLSR further improved model performance, particularly for acetate and tyrosine. Overall, the most effective approach varied by metabolite: VIP-PLSR was most suitable for cadaverine (R² = 0.79), putrescine (R² = 0.77), and tyramine (R² = 0.73); MVN augmentation was optimal for UMP (R² = 0.82); and the combination of VIP and augmentation showed the best performance for acetate (R² = 0.64) and tyrosine (R² = 0.88).

Conclusion: This study demonstrated that Vis/NIR spectroscopy combined with chemometric techniques is an effective nondestructive approach for monitoring chicken meat spoilage. Incorporating wavelength selection and spectral augmentation significantly enhanced the predictive performance of the PLSR models. The identification of key metabolites and spectral regions offers valuable insights into spoilage mechanisms, enabling real-time assessment of meat freshness. Future research should investigate alternative machine learning methods, including nonlinear models, to further improve prediction accuracy. Additionally, integrating advanced spectral preprocessing techniques may enhance model robustness across diverse storage and packaging conditions. These findings support the development of rapid, noninvasive quality control strategies in the poultry industry, contributing to reduced economic losses and improved consumer safety.

Funding Source: This work was carried out with the support of the National Research Foundation of Korea grant funded by the Korea government (MSIT; No. RS-2024-00453016).

Keywords: chicken, drip, Vis/NIR spectroscopy, data augmentation, nondestructive.

56 Impact of Toxic Fescue Consumption During Gestation on Muscle Growth Gene Expression and Beef Color Quality of the Offspring

Madison Blank^1,*, Paul Dahunsi¹, Morgan Denzer², Yan Huang³, Britni P. Littlejohn³, and Derico Setyabrata^1,3, ¹Department of Animal Science, University of Arkansas, Fayetteville, AR 72704, USA, ²Department of Food Science, University of Arkansas, Fayetteville, AR 72701, USA, ³Department of Animal Science, Division of Agriculture, University of Arkansas, Fayetteville, AR 72704, USA *blank@uark.edu

Introduction/Objectives: Endophyte-infected tall, toxic, fescue is the most common forage for beef cattle in the southeastern United States. However, exposure to this forage causes detrimental effects on the health of gestating cattle. The exposure to toxic fescue during gestation has been shown to impact fetal development during pregnancy and their offspring’s subsequent growth. However, limited information is currently available on the impact of this exposure on the meat quality of the offspring. Our objective is to determine how the dam’s consumption of toxic fescue during gestation impacts muscle growth gene expression and the beef color quality of the offspring.

Materials and Methods: A total of 22 animals (11 female offspring calves born to first-calf heifers that consumed toxic fescue seed [E+] and 11 heifer calves born to heifers that consumed endophyte-free fescue seed [E−] during mid-late gestation) were followed until harvest in a commercial facility. Prior to transportation to the feedlot, 6 animals from each group were randomly selected for a muscle biopsy from the longissimus lumborum between the 12th and 13th ribs to analyze muscle growth gene expression. All animals were then fed together in a single pen until they reached market weight and harvested together as a single group in a commercial processing facility. A section (∼6 cm) of striploin (longissimus lumborum; IMPS #180) from the opposite side of the biopsy site was collected on all carcasses at 3 d postmortem and transported to the Meat Science and Muscle Biology Laboratory at the University of Arkansas for further processing and analysis. Following arrival, the striploin sections were further cut into 3 equal pieces and randomly assigned into 3 different wet-aging durations: 1) no additional aging, 2) aged to 7 d, and 3) aged to 14 d. Samples assigned to aging were individually vacuum packaged, placed inside a box, and aged at 2°C. When the designated aging time was reached, the samples were subjected to pH and instrumental bloom color using Hunter MiniScan following 1 h of blooming. The study was a complete block design with a split-plot arrangement. Animals were the random effect, and both the feeding and aging periods were the fixed effects. Data were analyzed using the PROC GLIMMIX procedure of SAS. Least-square means were separated (F-test, P < .05).

Results: The expression of 3 genes (Pax7, MyoG and MSTN) were analyzed to identify the impact of toxic fescue consumption by dams during gestation on offspring growth potential. No significant impact was observed on the expression of any of the 3 genes. However, there was a tendency (P = .086) in the expression of Pax7, exhibiting higher expression in the E+ group compared to the E− group. No significant feeding or aging period effects were observed for pH, showing similar pH across all treatments. For bloom color, no feeding treatment impact was observed on any color traits (P > .05). A significant aging period effect, however, was observed on instrumental color traits. Greater lightness, redness, yellowness, hue angle, and chroma were measured on samples aged to 7 d and 14 d, compared to 0-d samples (P < .05).

Conclusion: The current results demonstrate that consumption of E+ by pregnant first-calf heifers during mid-late gestation has a minimal impact on the meat color quality of female offspring. Similar meat color quality was observed regardless of the treatment, although the duration of aging impacted bloom color quality. Further investigation into the impact of toxic fescue consumption during gestation on the meat tenderness quality and proteolytic characteristic of the offspring is currently in progress.

Funding Source: This project is partially funded by Arkansas Beef Council and University of Arkansas Honors College.

Keywords: aging, toxic fescue, bloom color, gene expression, prenatal programming.

57 Evaluating the Impact of Differing Surface Areas and Weights of Beef Striploin and Sirloin Steaks in Tri-Gas Modified Atmosphere Master Bags on Retail Display

Grace E. Harris^*, Morgan Pfeiffer, Ranjith Ramanathan, and Gretchen G. Mafi, Department of Animal and Food Sciences, Oklahoma State University, Stillwater, OK 74078, USA *gretchen.mafi@okstate.edu

Introduction/Objectives: Many factors impact fresh beef color including the chemical state of myoglobin, metmyoglobin reducing activity, oxygen consumption, and lipid oxidation. The case-ready industry employs master bags with an oxygen scavenger to extend the shelf life of polyvinyl chloride (PVC)-overwrapped trays in the meat case. However, no standards are available regarding surface area and/or weight that a single oxygen scavenger can optimally maintain. Filling the master bag with more meat than the oxygen scavenger can manage may have detrimental impacts on fresh meat color and ultimately shelf life. Limited research is available evaluating the effects of weight or surface area of meat in a master bag with oxygen scavengers. Thus, the objective of this study was to evaluate the impact of differing surface areas and weights of steaks in carbon monoxide (CO) modified atmospheric packaging (MAP) on shelf stability and to establish standards for optimal surface area and weight of meat for oxygen scavenger capacity.

Materials and Methods: Thirty-two (n = 32) US Department of Agriculture (USDA) low-choice beef striploins (IMPS #180) and 48 (n = 48) USDA low-choice top sirloin butts (IMPS #184) were obtained from a commercial processor and wet aged to 21 d postmortem. Loins were alternately cut based on different thicknesses required to obtain steaks for 3 weight treatments and 3 surface area treatments. The weight treatments (total weight of all steaks in the bag) were 2.7 kg (light weight [LW]), 3.6 kg (intermediate weight [IW]), and 4.1 kg (heavy weight [HW]) in their respective bags. The surface area treatments (total surface area of all steaks in the bag) were 216.70 cm² (small surface area [SS]), 266.45 cm² (medium surface area [MS]), and 422.15 cm² (large surface area [LS]). Top butts were alternately cut based on different thicknesses required to obtain steaks for 3 weight treatments and 2 surface area treatments. The weight treatments were 1.4 kg (LW), 2.7 kg (IW), and 3.6 kg (HW) of beef in their respective bags. The surface area treatments were 291.18 cm² (SS) and 396.86 cm² (LS). After slicing, steaks were placed into foam trays (n = 50 strip steaks; n = 46 sirloin steaks) with an absorbent pad and overwrapped with laser perforated PVC film. Trays were placed in master bags based on their designated treatment and flushed with 30% carbon dioxide, 0.4% CO, and 69.6% nitrogen gas with the addition of an oxygen scavenger. Bags were then held in dark storage for 15 d. Oxygen depletion and headspace analysis were conducted, and objective and subjective color measurements were collected during retail display (day 1–7 strips; day 1–6 sirloins). Muscle color and surface discoloration were evaluated by a trained panel (n = 6). Additionally, lipid oxidation, oxygen consumption, and metmyoglobin reducing activity analyses were conducted at the beginning and end of retail display. Data were analyzed using the GLIMMIX procedure of SAS 9.4. Least-squares were separated using the PDIFF option with differences considered significant at a P value less than .05.

Results: On days 1 to 5, treatments of strip steak surface area were similar (P > .05) in muscle color. On days 6 and 7, SS strip steaks were brighter (P < .05) than MS, while LS were similar (P > .05) to both SS and MS. There was no difference (P > .05) in muscle color between weight treatments of strip steaks on any day of retail display. On day 1 for sirloin steaks, SS master bags were brighter (P < .05) than LS; however, on days 2 through 6, surface area treatments were similar (P > .05) in muscle color. On retail day 1, IW master bags were brighter (P < .05) than LW, while HW master bags were similar (P > .05) to LW and IW. On days 2 through 6, there was no difference (P > .05) between sirloin steak weight treatments for muscle color. There was no difference (P > .05) in surface discoloration between treatments on any day for strip steak surface area or sirloin steak surface area or weight treatments. Strip steak weight treatments were similar (P > .05) in surface discoloration on days 1 to 4; however, on days 5 and 6, strip steaks from LW bags were more discolored (P < .05) than IW and HW. Then again on day 7, there was no difference (P > .05) in discoloration between strip steak weight treatments. On day 1 and days 3 to 7 of retail display, a* values were similar (P > .05) between surface area and weight treatments of strip steaks. However, on day 2 of retail display, strip steaks from SS and MS master bags were redder (P < .05) than LS, and LW steaks were redder (P < .05) than IW and HW. On days 1 through 3, SS sirloin steaks were redder (P < .05) than LS but no different on days 4 through 6. IW bags of sirloin steaks were redder (P < .05) than LW and HW on day 1, then treatments of weight were similar (P > .05) for the remainder of retail display. No treatment effect (P > .05) was observed for either cut for lipid oxidation, oxygen consumption, or metmyoglobin reducing activity. Generally, lipid oxidation increased numerically, while oxygen consumption and metmyoglobin reducing activity decreased numerically from the beginning to end of retail display.

Conclusion: Utilizing CO-MAP master bags has been proven to improve meat color. Establishing standards for the surface area and/or weight of meat with oxygen scavengers in master bags is important for improving color stability and the shelf life of beef products. More specifically, if an oxygen scavenger cannot consume oxygen within a master bag due to greater meat surface area or weight, this can be detrimental to meat color. The scavenger utilized in this study had enough capacity to overcome the additional weight or surface area exposed within the master bag.

Funding Source: National Cattlemen’s Beef Association—Beef Checkoff.

Keywords: beef, retail color, packaging.

58 Similarities in the Muscle Fiber Characteristics Among Major Caprine Skeletal Muscles

Jaehoon Baek^1,*, Junyoung Park¹, Sumin Song¹, Huilin Cheng¹, Hyun-Jun Kim², and Gap-Don Kim^1,2,3, ¹Graduate School of International Agricultural Technology, Seoul National University, Pyeongchang-gun, Gangwon-do 25354, Republic of Korea, ²Institutes of Green Bio Science & Technology, Seoul National University, Pyeongchang-gun, Gagwon-do 25354, Republic of Korea, ³Research Institute of Agriculture & Life Science, Seoul National University, Seoul 08826, Republic of Korea *bjh0607@snu.ac,kr

Introduction/Objectives: Muscle fiber characteristics are crucial factors in understanding not only the conversion of skeletal muscle into meat but also the physicochemical properties of meat. Furthermore, understanding the similarities (or differences) in the muscle fiber characteristics of various skeletal muscles helps to understand the quality differences among meat cuts. Therefore, the aim of this preliminary study was to evaluate the similarities in the muscle fiber characteristics of major caprine skeletal muscles to identify the diversity in the meat quality characteristics of goat meat cuts.

Materials and Methods: Longissimus thoracis et lumborum (LTL), semimembranosus (SM), semitendinosus (ST), psoas major (PM), diaphragm (DP) muscles were obtained from 2 goat half carcasses (12 kg, male, 4 mo of age) after chilling at 4°C for 24 h. For the analysis of muscle fiber characteristics, muscle samples were prepared by cutting into pieces (1.0 × 1.0 × 1.0 cm) and immediately freezing in 2-methylbutane chilled with liquid nitrogen. Transversal and longitudinal sections (10-μm thickness) were obtained from each sample using cryostat microtome (CM1520; Leica Biosystems, Wetzlar, Germany). Sections were blocked in 10% normal goat serum (Cell Signalling Technology, Danvers, MA), and stained with 3 different myosin heavy chain (MHC) isoform-specific primary (BA-F8, anti-MHC slow/I; SC-71, anti-MHC IIA; 6H1, anti-MHC IIX; DSHB, Iowa City, IA) and secondary (anti-immunoglobulin G and anti-immunoglobulin M conjugated with fluorescent dyes such as AlexaFluor 405, 488, and 594; Thermo Fisher Scientific, Waltham, MA) antibodies. The sections were visualized using a fluorescence microscope (EVOS M5000; Thermo Fisher Scientific, Waltham, MA), and 3 different regions were captured for analysis of the cross-sectional area (CSA; μm²), relative fiber area (RFA; %), fiber density (number/mm²), fiber length (μm), and muscle bundle size (μm²), using Image Pro Plus (Media Cybernetics, Rockville, MD). To compare muscle fiber characteristics among different types of muscles, 1-way analysis of variance and Duncan’s multiple range post-hoc test were performed using SAS (v. 9.4, SAS Institute, Cary, NC). Differences were considered at a P value less than .05. To analyze the similarities in muscle fiber characteristics among the muscles, a hierarchical cluster analysis (HCA) was performed.

Results: In the comparison of the muscle fiber bundle size, ST showed a significantly lower value than DP, LTL, and PM (P < .05), whereas no significant difference was observed from SM (P > .05). The DP exhibited to have no type IIX fiber. The length of the type I fibers were significantly higher in the LTL than in other muscles (P < .05). The LTL had significantly longer type IIA than the other muscles, whereas the SM had the shortest (P < .05). In the length of IIX, a significant difference was found between the PM and ST. The PM showed a shorter length than ST (P < .05). The DP and ST appeared to have larger type I CSAs than the LTL and SM (P < .05). In addition, the type IIA CSA was significantly larger than the LTL (P < .05); however, no significant differences were observed for type IIX (P > .05). In the RFA, the DP and PM showed significantly higher proportions of type I than other muscles (P < .05). Among the muscles, the type I ratio of the LTL was significantly lower than that of the SM and ST (P < .05). The proportion of type IIA in the DP was significantly higher than that in the other muscles (P < .05). The relative area of type IIX in the LTL was significantly higher than that in the other muscles and in the PM was the lowest (P < .05). The PM exhibited the highest type I fiber density, followed by DP, SM, LTL, and ST (P < .05). The type IIA fiber densities of the DP and LTL were significantly higher than those of ST, SM, and PM (P < .05). Additionally, the LTL exhibited significantly higher fiber density of type IIX than other muscles (P < .05). A significant difference in total fiber density was found between LTL and ST (P < .05). Analysis of the similarity (HCA) between muscles revealed that the SM and PM had the highest similarity with each other. These 2 muscles exhibited very similar characteristics in terms of muscle fiber length and density, regardless of the muscle fiber type. In addition, they showed a relatively higher similarity with the ST than to the LTL and DP, whereas the DP, which did not contain IIX fibers, appeared to have the lowest similarity with all other muscles.

Conclusion: Among the muscle fiber characteristics of the 5 goat skeletal muscles, the DP muscle showed distinct characteristics compared with the other muscles, specifically the absence of IIX fibers, resulting in the lowest similarity in muscle fiber characteristics with the other 4 muscles. The PM and SM muscles exhibited the highest similarity, with similar sizes and densities of muscle fibers, whereas the LTL muscle showed a low composition of type I fibers. These results will help understand the physicochemical differences or similarities among different types (cuts) of goat meat.

Keywords: goat, skeletal muscles, muscle fiber characteristics.

59 Impact of Sodium Bicarbonate Inclusion Upon Texture, Sensory Ratings, Cooked Color, and pH of Ground Beef Patties

Megan E. Eckhardt^*, Ty E. Lawrence, Loni W. Lucherk, and Trent E. Schwartz, West Texas A&M University, Canyon, TX 79016, USA *aarangel1@buffs.wtamu.edu

Introduction/Objectives: Product enhancers, such as sodium bicarbonate, have allowed meat processors the ability to elevate product palatability levels for consumers. Our objective was to evaluate the impact of sodium bicarbonate inclusion rate in ground beef patties upon subjective and objective measures of beef palatability.

Materials and Methods: Ten ground beef chubs with an 80 out of 20 lean-to-fat percentage were used, and each replicate was of similar lot numbers and/or freeze-by dates. Ground beef was stored unfrozen at 35°C prior to patty fabrication. Pure baking soda was incorporated into ground beef at 1 of 4 levels (0%, 0.25%, 0.50%, 1.0%), and immediately after patty fabrication, pH values were recorded. Raw patty instrumental color (L*, a*, b*) in polyvinyl chloride overwrap was obtained during a simulated retail display beginning at day 0 and continuing every 12 h throughout a 5-d period. Patties were then cooked to an average peak-end-point temperature of 78.1°C on a clamshell grill set to a surface temperature of 177°C, and overall cook loss was calculated. Descriptive sensory attributes (beef odor, soapy/alkaline odor, overall juiciness, overall tenderness, beef flavor identity, beef flavor intensity, springiness/gumminess, soapy/alkaline flavor, and bitter flavor) were evaluated by trained sensory panelists. Attributes were based on a 100-point continuous-line scale (0 = none; 50 = moderate; 100 = extremely). Patties designated for objective tenderness were allowed to cool at 3.5°C for approximately 3 h prior to testing. Allo-Kramer shear force (AKSF) was measured on a portion (4.2 × 3.5 cm) of patty removed from the center, across the width of the patty.

Results: Combining ground beef with sodium bicarbonate resulted in a linear increase in pH values as inclusion rate increased, with the 1.0% treatment having the highest pH value (P < .001). AKSF values decreased linearly as sodium bicarbonate levels increased. Patties that included 0.25%, 0.50%, and 1.0% sodium bicarbonate had AKSF values that were 8.5%, 17.1%, and 26.8% lower (P < .001) than patties that did not contain sodium bicarbonate. Cooking losses were similar (P ≥ .664) between 0.0%, 0.25%, and 0.50% sodium bicarbonate treatments, with notably less (P < .001) cooking losses for patties that included 1.0% sodium bicarbonate. Sensory analysis outcomes revealed that as the percentage of sodium bicarbonate increased, beef odor decreased (P < .001) slightly for 0.50% inclusion and notably for 1.0% inclusion. Beef odor was not different between 0.0% and 0.25% sodium bicarbonate inclusion treatments (P = .713). Soapy/alkaline odor was minimal for 0.0% and 0.25% treatments and increased substantially for 0.50% and 1.0% treatments (P < .001). Overall juiciness did not differ (P ≥ .256) between 0%, 0.25%, and 0.5% inclusion treatments, all of which were rated less juicy (P < .002) than patties containing 1.0% sodium bicarbonate. Overall subjective tenderness differed (P < .001) among treatments; however, no meaningful pattern was identified. Beef flavor identity and beef flavor intensity diminished as sodium bicarbonate inclusion increased (P < .001). In contrast, springiness/gumminess, soapy/alkaline flavor, and bitter flavor sensory ratings increased as sodium bicarbonate inclusion increased (P < .001). Regarding objective color, L* values were the highest for 0.0% sodium bicarbonate patties and progressively decreased as sodium bicarbonate level increased (P < .001). Over the 5-d display period, a* values were highest (P < .001) for 1.0% sodium bicarbonate patties and lowest for those containing 0.0% or 0.25%. Inclusion of sodium bicarbonate in the ground beef patties improved fresh red beef color life.

Conclusion: We observed positive impacts on functional and objective properties and negative impacts on sensory properties when ground beef was incorporated with sodium bicarbonate. Future research should focus on determining an effective inclusion rate that will improve beef patty color life and physiochemical traits without negative sensory characteristics.

Funding Source: Ronald E. McNair Post-Baccalaureate Achievement Program and Caviness Meat Science & Innovation Center.

Keywords: AKSF, tenderness, juiciness, sodium bicarbonate.

60 Effect of Lubabegron Fumarate on Carcass Characteristics, Steak Dimensionality, Sensory Analysis, and Shear Force of Beef Steers

Lindsey K. Decker^*, Blake A. Foraker, Bradley J. Johnson, Jerrad F. Legako, J. Chance Brooks, Markus F. Miller, and Dale R. Woerner, Texas Tech University, Lubbock, TX 79409, USA *lidecker@ttu.edu

Introduction/Objectives: Lubabegron fumarate (LUB) is the most recently approved β-agonist for use in feedlot cattle, introducing a novel label approval for reduction of ammonia gas emissions per unit of live or carcass weight. Since its approval, it has become widely used across the feedlot industry. However, current research on the effects of LUB on meat quality focuses on specific cattle types, such as heifers and Holstein steers, and thus far has excluded Bos indicus-influenced cattle. Therefore, the purpose of this study was to evaluate the effects of LUB on an industry-representative cattle population.

Materials and Methods: Pens of cattle either fed LUB or not (CON) were identified from 18 lots across 3 major US cattle feeding regions (high plains of Texas, southwest Kansas, and the upper Midwest). A subsample of paired striploins (n = 200 pairs) from each lot was collected. Carcass camera data were collected from each lot. Each lot had an even split of upper 2/3 choice and low-choice quality grades. Once transported to the Texas Tech Meat Laboratory, each pair of striploins was divided into 6 chunks, and each chunk was assigned to an aging treatments: 3 d, 7 d, 14 d, 21 d, 28 d, and 35 d postmortem. A steak yield test was performed. Upon reaching the designated aging period, each chunk was fabricated into 2.54-cm steaks and assigned to 1 of the following assays: trained sensory analysis, shear force, and laboratory assay. Prior to freezing, each steak was imaged for steak dimensionality analysis on a gridded background. Steak numbers were recorded from the anterior to posterior end of the loin. Images were processed using ImageJ, and the following attributes were measured: steak area (cm²), steak length (cm), and steak width at 25%, 50%, 75%, and 87.5% the length of each steak (cm). Steaks for sensory and shear analysis were cooked in a combi-oven to a target peak internal temperature of 71°C. Sensory evaluations were conducted on samples aged 14 d and 28 d by 6 trained panelists per panel using a 15-point line scale. Warner-Bratzler shear force (WBSF) and slice shear force (SSF) were performed on all aging periods. Data were analyzed in R statistical software. Sensory attributes, shear force values, and steak dimension measurements were analyzed using linear mixed models, with treatment, aging period, and quality grade as fixed effects. Kill date served as a random effect. Peak temperature was included as a covariate. Within the model, it was accounted that aging periods were nested within the same carcass, and thus repeated measures. A multivariate analysis of variance was performed on sensory data. In univariate and multivariate analysis, main effects were interpreted when interactions were not significant and α was set at 0.05.

Results: While carcass data were not evaluated using statistical methods, least-squares means were calculated for each treatment. Lots fed LUB had a higher percentage of cattle grading US Department of Agriculture select (6.5%) compared to CON cattle. Moreover, LUB lots had numerically heavier average hot-carcass weights and a larger longissimus muscle area. Steak yield tests indicated that LUB treatment resulted in heavier untrimmed striploin weight, (P = .001), higher total steak weight (P < .001), and increased average individual steak weight (P = .003). However, LUB and CON samples were not different for average steak number (P = .07), and overall steak yield in proportion to total striploin weight (P = .88). Overall steak area, length, and all width measurements were not affected by LUB treatment (P > .11). Trained sensory evaluation resulted in no significant 2- or 3-way interactions (P > .41). LUB feeding decreased muscle fiber tenderness, brown/roasted and fat-like flavor, SSF values, paired with increased connective tissue amount, sour, and liver-like flavors. Moreover, steaks aged 28 d were found to be more tender and have less connective tissue than samples aged 14 d (P < .05). Furthermore, upper 2/3 choice samples were rated higher for juiciness and umami flavor than low-choice samples. Moreover, there were no 2- or 3-way interactions in the multivariate analysis of variance (P > .61). There were differences in LUB treatment, aging period and quality grade (P < .001), likely driven by the univariate sensory differences. Similarly, all 2- or 3-way interactions among treatment, aging period, and quality grade for WBSF were not significant (P > .42) as well as the main effect of LUB treatment (P = .98). Moreover, there was no significant 2- or 3-way interaction for SSF. Upper 2/3 choice samples resulted in lower SSF and WBSF values than low-choice samples (P < 0.01). Both SSF and WBSF values decreased as the aging period increased (P < .001). In both methods, 3-d samples had the greatest shear force values, while 28 d and 35 d had the lowest shear force values.

Conclusion: As a whole, the current work indicates both positive and negative impacts related to the feeding of LUB. An overall decrease in tenderness and shear force values is not unexpected with the use of LUB. Increases in steak yield, paired with the numerical increases in hot-carcass weight and camera longissimus muscle area by LUB, indicate a likely increase in overall muscle deposition, though they likely drive the tenderness decrease. While LUB is labeled for the reduction of ammonia gas emissions, the current evidence of increasing lean muscle indicates a further benefit to the beef industry, though negative quality impacts cannot be ignored.

Funding Source: Research coordinated by the National Cattlemen’s Beef Association, a contractor to the Beef Checkoff.

Keywords: lubabegron, beef quality, sensory, tenderness.

61 Predicting Beef Carcass Yield Using 3-Dimensional Imaging

Cooper J. Carter^*, Andres Mendizabal, Harshit Parmar, Chris Monico, Blake A. Foraker, Markus F. Miller, and Dale R. Woerner, Texas Tech University, Lubbock, TX 79416, USA *coopcart@ttu.edu

Introduction/Objectives: Despite significant advancements in imaging and computational analysis, carcass grading remains limited by traditional methodologies. The current US Department of Agriculture (USDA) beef yield grade equation employs only 3 independent variables for yield estimation; however, these predictors fail to capture the conformation variability present in modern beef carcasses. In contrast, 3-dimensional (3D) imaging offers a robust, noninvasive technique capable of quantifying detailed spatial information that could enhance predictive yield models. 3D imaging leverages advanced image processing to provide objective, consistent, and quantitative assessments of carcass dimensionality. Unlike conventional methods that rely primarily on numerical tables or matrices, machine learning models such as MeshGNN can represent each carcass scan as a graph structure composed of interconnected nodes (vertices) and edges (connections between vertices). This study assesses the application of cross-sectional and linear measurements derived from 3D images and 3D imaging techniques in predicting the saleable yield (SY) of beef carcasses.

Materials and Methods: A combination of steers, heifers, and bulls were harvested at the Texas Tech University Meat Laboratory (N = 40) following standard industry practices. After harvest, carcasses were chilled for 6 d. During chilling (at least 24 h postmortem), carcasses were 3D imaged as intact sides using the Polycam^® software powered by an Apple^® iPad Pro 6th generation (Polycam^®). Carcasses were then separated between the 12th and 13th ribs, and 3 trained grader personnel from Texas Tech University collected ribeye area (in²) and preliminary yield grade using a grid and probe. The grade data were averaged across the 3 graders. Carcasses were fabricated into boneless subprimals and wholesale cuts by trained facility personnel from Texas Tech University. Each wholesale cut was further divided into 4 components: subprimals, lean trimmings (trim), fat trimmings (fat), and bone. The final fat specifications of subprimal cuts varied according to the specific subprimal, ranging from 0 cm to 0.64 cm. All components were weighed and verified using a weigh-back system. OBJ files created by Polycam^® were imported into 3D processing software, where filters were applied to clean and repair sections of the mesh clouds. For each cross-section, the area, perimeter, and α complex shape were calculated. Additionally, linear measurements were obtained by manually identifying landmarks on the carcass and calculating the distances between them. Neural networks and XGBoost regression models were developed in Python 3.11 to predict carcass yield based on linear measurements derived from the 3D images. Additionally, a graph-based neural network (GNN) model was developed using 3D mesh data. The dataset consisted of OBJ mesh files and the corresponding SY labels. Vertices were normalized by setting a common origin coordinate. Global descriptors such as mesh volume, surface area, bounding box dimensions, and variance from centroid distances were computed. Meshes were encapsulated into Torch Geometric data objects, including node and global features. All models were trained using a dataset split into a combined training/testing set (70%) and a validation set (30%), with stratification based on calculated yield quantiles to maintain proportional representation of different yield levels across the splits.

Results: Despite the small dataset (N = 40), the variation in carcass traits is considerable, as each yield grade category is represented. Using USDA yield grade predictors in combination with a neural network, an R² of −0.61 was obtained, indicating poor model performance. Additionally, the learning curves for the training and validation datasets did not demonstrate convergence. This lack of convergence is primarily attributed to the insufficient number of observations available for model training. Using linear measurements derived from the 3D images, similar results (R² = −0.109) and a lack of convergence were observed, further indicating inadequate training. Again, this limitation is likely due to the restricted sample size rather than the absence of a predictive relationship between these geometric variables and SY. To address this, identical models were built using XGBoost instead of neural networks for both USDA yield grade predictors and linear measurements derived from 3D images. When using USDA yield grade predictors, the model demonstrated a negative R², indicating poor predictive performance. However, when using an XGBoost model incorporating cross-sectional and linear measurements, a positive R² was achieved, explaining approximately 7% of the variation in SY. Despite its modest predictive performance, this approach still outperformed the model trained exclusively with current yield grade predictors, suggesting that incorporating additional geometric measurements may enhance predictive capability. Additionally, the low explanatory power (7%) does not fully represent the predictive potential of these variables, as model performance in this study is constrained by the limited sample size. Due to the small number of available observations, the present study adopted a novel approach. 3D images of beef carcasses can be represented as “mesh clouds,” containing detailed vertex information described by coordinates (X, Y, Z). To analyze complex 3D data, a specialized machine learning model, MeshGNN, was developed based on GNN. This model effectively captured both detailed local geometric characteristics and broader structural information for prediction purposes. The final predictive feature set combined 64 node-derived features with 6 global geometric descriptors, creating a comprehensive 70-dimensional representation. Visualization of the training process through loss curves, combined with an achieved R² of 0.60, demonstrated a consistent reduction in prediction error across epochs, indicating effective model convergence and successful learning despite the limited number of training samples. Additionally, the mean squared error and mean absolute error suggest that, on average, predictions deviate by approximately 1.5%.

Conclusion: The convergence observed in the learning curves further supports the notion that the features generated by the GNN, combined with global carcass features, hold significant predictive potential for estimating SY in beef carcasses. It is important to acknowledge that the obtained R² value of 0.60 may not represent the maximum predictive capability achievable through 3D imaging, as the observed performance could be constrained by the limited sample size. Nevertheless, considering that this performance is comparable to a model previously trained on more than 700 observations using USDA yield predictors and cattle type, these results strongly support the potential of 3D imaging as a valuable predictive tool for SY estimation in beef carcasses.

Funding Source: The project was funded by the National Cattlemen’s Beef Association.

Keywords: beef, yield, 3D imaging, machine learning.

62 Prediction of Sensory Tenderness and Sensory Juiciness for Pork Loins Using Instrumental Pork Quality Measurements

Rebecca A. Brown^*, Yifei Wang, Milena Conte, and Benjamin M. Bohrer, Department of Animal Sciences, The Ohio State University, Columbus, OH 43210, USA *brown.8357@osu.edu

Introduction/Objectives: One of the major challenges in the pork industry is inconsistency in eating experience as well as defining leading contributors to a positive eating experience. Eating experience is primarily influenced by sensory traits such as tenderness, juiciness, and flavor, all of which play critical roles and significantly shape consumer’s perception of pork. While flavor can be difficult to predict by instrumental means, research groups routinely use instrumental pork quality measurements such as shear force, instrumental color, and pH to gain insight into perceptions of sensory tenderness and sensory juiciness. The objective of this study was to determine prediction abilities of instrumental pork quality measurements for sensory tenderness and sensory juiciness.

Materials and Methods: Pork loins (longissimus thoracis; 2.54-cm thick chops; n = 139) were aged for a period of 7 d postmortem. Ultimate pH (referred to as pH) was measured using a calibrated pH meter (Meat Probes Inc.), and instrumental color was measured with a Minolta CM-700d colorimeter (D65 light source, 10° observer, 11-mm aperture; Konica Minolta Sensing Americas Inc.). Intramuscular fat (IMF) content was determined using a drying oven and Soxhlet ether extraction methods. Shear force chops were cooked with the sous-vide cooking technique in a laboratory water bath (set to 80°C) until an internal endpoint cooking temperature of 71°C was reached. Cores were removed from each cooked chop parallel to the longitudinal orientation of the muscle fibers and sheared with a Warner-Bratzler shearing device equipped to a TA.XT Plus 100 Connect texture analyzer (Texture Technologies). Sensory samples were cooked to an internal temperature of 71°C using the sous-vide cooking technique, which consisted of a 40-min cooking time in an 80°C water bath. Descriptive sensory attributes, including tenderness and juiciness, were evaluated using a 15-cm line scale with anchors at 0, 7.5, and 15. Pearson correlation coefficients were calculated among all parameters using the CORR procedure of SAS (SAS Institute Inc.). Two stepwise regression models (sensory tenderness or sensory juiciness serving as the dependent variables and pH, Minolta L*, Minolta a*, Minolta b*, IMF, and Warner-Bratzler shear force [WBSF] serving as the independent variables) were generated with the REG procedure of SAS. Significance level thresholds for a variable to be added to the model were set to P ≤ .15. Simple linear regression models generated with the REG procedure of SAS were used to generate predicted levels of tenderness using WBSF and juiciness using pH. Sensory tenderness and juiciness levels were further categorized into discrete variables ranging from 3 to 10 and 2 to 9, respectively, to establish thresholds for tenderness and juiciness. Thresholds for tenderness and juiciness categories were analyzed accordingly using the GLIMMIX procedure of SAS for the response variables WBSF and predicted tenderness for tenderness thresholds and for the response variables pH and predicted juiciness for juiciness thresholds.

Results: The samples used for this analysis provided an industry-representative population with an appropriate level of variation (pH: mean = 5.64, SD = 0.20, range = 5.27–6.39; Minolta L*: mean = 54.8, SD = 4.8, range = 45.1–67.4; IMF: mean = 3.23%, SD = 2.04%, range = 0.45–10.61%; WBSF: mean = 2.79 kg, SD = 0.58 kg, range = 1.29–4.42 kg; sensory tenderness: mean = 7.00, SD = 1.71, range = 3.65–12.08; sensory juiciness: mean = 5.21, SD = 1.78, range = 2.28–9.85). The first regression model (sensory tenderness = −9.13819 – 1.33314 [WBSF] + 3.28135 [pH] + 0.11807 [IMF] – 0.13928 [Minolta a*] + 0.15047 Minolta b*]) explained 42.9% of the variation in sensory tenderness, with WBSF contributing the greatest amount of variation at 27.7%, followed by IMF at 7.7%, pH at 6.2%, Minolta a* at 1.2%, and Minolta b* value at 1.1%. Minolta L* failed to enter the model at a selection of a P value of .15. The second regression model (sensory juiciness = –17.57814 – 4.41578 [pH] + 0.29806 [IMF] – 0.05592 [Minolta L*]) explained 34.5% of the variation in sensory juiciness with pH contributing the greatest amount of variation at 25.0%, followed by IMF at 8.2%, and Minolta L* at 1.2%. Tenderness thresholds were described as tough at a score of 3 (mean WBSF = 4.12 kg, mean predicted tenderness = 4.92), slightly tough at a score of 4 to 6 (mean WBSF = 3.07–3.23 kg, mean predicted tenderness = 6.31–6.57), moderately tender at a score of 7 to 9 (mean WBSF = 2.45–2.76 kg, mean predicted tenderness = 7.05–7.53), and tender at a score of 10 (mean WBSF = 2.17 kg, mean predicted tenderness = 7.97). Juiciness thresholds were described as dry at a score of 2 and 3 (mean pH = 5.53, mean predicted juiciness = 4.80–4.84), dry to moderately juiciness at a score of 4 to 6 (mean pH = 5.59–5.61; mean predicted juiciness = 5.00–5.11), moderately juicy at a score of 7 (mean pH = 5.70; mean predicted juiciness = 5.52), and juicy at a score of 8 and 9 (mean pH = 5.93–5.99; mean predicted juiciness = 6.57–6.80).

Conclusion: These results indicated that WBSF and pH served as moderate predictors for sensory tenderness and sensory juiciness, respectively. IMF and instrumental color (measured with a Minolta colorimeter in this study) were weak predictors for both sensory tenderness and sensory juiciness. At an endpoint cooking temperature of 71°C, pork loin chops were generally perceived as slightly tough and dry by the trained sensory panelists in this study. A WBSF threshold of 2.53 kg or less and a pH of 5.70 or greater may provide some assurance that pork loins would be at least moderately tender and moderately juicy; however, greater research efforts are likely required before widescale adoption of these pork quality measurements because they were only moderate predictors of sensory attributes.

Funding Source: This study received in kind support by Kalmbach Nutritional Services.

Keywords: pork quality, eating experience.

63 Evaluating Changes in Organoleptic Traits and Objective Color of Ground Beef During a Retail Display Period

Samuel F. Stickley^*, Lauren M. Frink, Stephanie L. Witberler, Mason J. Prester, Chesney A. Effling, Greta E. Huber, Erin S. Beyer, Michael D. Chao, Morgan D. Zumbaugh, Jessie L. Vipham, and Travis G. O’Quinn, Kansas State University, Manhattan, KS 66506, USA *sstick@ksu.edu

Introduction/Objectives: Ground beef is an affordable and versatile staple for consumers, therefore driving substantial market demand. However, the beef industry loses nearly $1.48 billion annually due to the discoloration of ground beef. Despite the discoloration that deters consumers from purchasing, a large portion of the meat removed from shelves prior to reaching its full shelf-life potential remains safe for consumption. However, the palatability of ground beef that is past the conclusion of its visual shelf life has never been evaluated. Therefore, the objective of this study was to evaluate trained sensory panel organoleptic traits and objective color measurements throughout and past the shelf life of ground beef.

Materials and Methods: In this study, 454 g ground beef (80% lean) packages were sourced from a commercial case-ready ground beef facility. Product was stored at 2°C to 4°C in gas-flushed motherbags in the absence of light, with each motherbag containing 4 individual packages. Paired packages (N = 128) from each motherbag were randomly assigned a display day (0, 2, 4, 6, 8, 10, 12, and 14 d) and placed in coffin-style retail cases at 2°C to 4°C. On each display day, L*, a*, and b*, as well as spectral data were collected using a HunterLab MiniScan Spectrophotometer. These readings were used to calculate the percentage of oxymyoglobin, and metmyoglobin according to the American Meat Science Association color guidelines (AMSA, 2012). Trained sensory panelists evaluated visual appearance, touch, odor, and palatability characteristics: juiciness, tenderness, texture, beef flavor intensity, and off flavor. Panelists were trained according to the AMSA meat color measurement guidelines (AMSA, 2012) and used a 100-point line scale for all characteristics. Redness and discoloration were evaluated with anchors at 0 (extremely dark red and 0% discoloration) and 100 (bright, cherry red and 100% discoloration). Touch, odor, and palatability panelists were trained using samples with various characteristics anchored to their respective scales (0 = characteristic beef texture, no off odor present, extremely dry, tough, soft, bland beef flavor, and no off flavor; 100 = noncharacteristic beef texture, extreme off odor, extremely juicy, tender, firm, intense beef flavor, and extreme off flavor). Samples for palatability evaluation were cooked on clamshell style grills set to 177°C to an internal temperature of 82°C. Trained panelists evaluated touch, odor, and palatability characteristics under red lights to avoid any bias toward sample color. Panelists recorded their responses using electronic tablets, using a digital survey. Data were analyzed as a completely randomized design utilizing SAS PROC GLIMMIX, with day set as a fixed effect and α at 0.05.

Results: Objective color measurements showed L* values decreased (P < .05) across the display period. Day 0 had the highest (P < .05) L* value and day 14 the lowest (P < .05). Similarly, a* values peaked on day 0, declined until day 10, then increased by day 14 (P < .05). The b* values were the highest (P < .05) on day 0, then decreased through day 10, with days 8 and 10 being similar (P > .05). Metmyoglobin percentage increased through day 10, which had the highest (P < .05) percentage of metmyoglobin. Following day 10, the percentage of metmyoglobin decreased, ending with day 14, remaining higher (P < .05) than days 0 through 6. Trained panel evaluations indicated redness values were highest on day 0 (P < .05), declining through day 8 (P < .05). Samples from days 8, 10, and 12 remained similar (P > .05) in redness values, then increased on day 14 (P < .05). Discoloration increased over time, with day 0 and 2 samples showing the lowest values (P < .05). The greatest discoloration percentage occurred on days 8 and 10 (P < .05), followed by a decrease (P < .05) from days 10 to 14. Trained odor evaluation showed an initial decrease (P < .05) from day 0 to day 2. Off odors increased consistently throughout display, culminating in day 14 having a higher (P < .05) off odor score, similar (P > .05) only to day 0. Touch scores evaluated by trained sensory panelists showed a decrease (P < .05) from day 0 to day 4, then remained similar (P > .05) through day 10. After day 10, touch scores increased (P < .05) each day of display, with day 14 having the highest (P < .05) noncharacteristic beef touch. Surprisingly, trained panelists found no differences (P > .05) in beef flavor intensity and off flavor during display. Contrastingly, juiciness scores decreased (P < .05) until day 12, when a rise in juiciness was observed. Additionally, tenderness scores were the highest (P < .05) on the initial days of display, days 0 and 2, and then decreased, with days 8, 10, and 12 having the lowest (P < .05) tenderness values. Lastly, texture scores followed an inverse trend to juiciness and tenderness, increasing (P < .05) throughout display, with days 6, 8, 10, and 12 being the firmest (P < .05).

Conclusion: The quality of ground beef deteriorated steadily throughout the 14-d display period, with significant reductions in redness, juiciness, tenderness, and texture, alongside increased discoloration and off odors. Objective color measurements supported these trends, as L*, a*, and b* values decreased consistently, while the percentage of metmyoglobin increased. Interestingly, samples with the lowest redness, a* values, and highest percentage of discoloration and percentage of metmyoglobin, showed no differences in beef flavor intensity or off flavors compared to all other days of display. This indicates palatability may not be a good indicator of shelf life. This study provides valuable insight into the timeline of quality degradation throughout a display period, contributing to a better understanding of ground beef shelf life.

Funding Source: Kansas State University.

Keywords: color, ground beef, organoleptic, shelf life.

64 Color Stability and Flavor Profile of 6 Beef Muscles

M. Sebastian Hernandez^* and Jerrad F. Legako

Texas Tech University, Lubbock, TX 79409, USA *Sebastian.Hernandez@ttu.edu

Introduction/Objectives: Beef quality attributes such as color stability and flavor profile are modulated by intrinsic biochemical features. Muscle fiber type is very influential, as specific muscle fiber types possess divergent metabolism and physiochemical attributes. Oxidative, or red, muscles have been reported to be more color labile compared to glycolytic, white muscles. From a flavor perspective, divergent metabolisms may provide different pools of flavor precursors. Therefore, the objectives of this study were to evaluate the color stability and palatability of 6 beef muscles known to vary in muscle fiber type and fat content.

Materials and Methods: Fifteen beef carcasses with a marbling score of moderate (600–699) and no quality defects were selected from a commercial processing facility in west Texas. Beef striploins (IMPS #180), tenderloins (IMPS #189), goosenecks (IMPS #170), chuck rolls (IMPS #116), and top blade roasts (IMPS #114D) were collected from 1 side of each carcass 48 h postmortem. Subprimals were transported at (0–4°C) to the Gordon W. Davis Meat Laboratory in Lubbock, Texas. Upon return to the meat laboratory, subprimals were immediately fabricated into M. Longissimus lumborum (LL), M. Psoas major (PM), M. Semitendinosus (ST), M. Biceps femoris (BF), M. Infraspinatus (IF), and M. Serratus ventralis (SV) steaks. Four steaks from each subprimal were assigned to either simulated retail display or descriptive sensory analysis. Steaks were vacuum sealed and wet aged for 14 d. Following aging, steaks were either frozen (−20°C) for sensory evaluation or packaged in polyvinyl chloride overwrap packaging and subjected to a 168-h simulated retail display. Moreover, oxygen consumption and metmyoglobin reducing activity were conducted. Every 12 h, instrumental color was measured (L*, a*, b*, hue, chroma, surface myoglobin), and trained panelists measured visual color and percent discoloration. For descriptive sensory analysis, panelists were trained for 30 h to evaluate 11 flavor aromatics, 5 basic tastes, and 3 texture attributes on a 16-point scale. Within each sensory session, 6 samples were evaluated. Steaks were cooked on a flat-top grill set to 162.7°C to an internal temperature of 71°C. Instrumental and visual color data were analyzed as randomized block design with repeated measures, where carcass served as the block and muscle, hour, and their interaction served as fixed effects. Oxygen consumption, metmyoglobin reducing activity, and sensory data were analyzed as a randomized block design, where carcass served as the block and muscle served as the fixed effect. For sensory data, sensory session and feed order served as random effects. Significance was determined at a P value of less than .05.

Results: A muscle by hour interaction was observed for L*, a*, b*, percentage of metmyoglobin, percentage of oxymyoglobin, visual color, and percentage discoloration (P < .05). Regardless of the display time, the ST had the greatest L* value compared to all other muscles (P < .05). After 24 h, the LL maintained the greatest a* value and visual color score compared to all other muscles (P < .05). From 60 h to 108 h, the IF developed the most surface metmyoglobin compared to all other muscles (P < .05). Conversely, from 72 h to 156 h, except for 96 h, the LL had the least development of surface metmyoglobin (P < .05). Of the 19 sensory attributes, 18 were different among muscles (P ≤ .03). The PM was the most tender muscle compared to all other muscles, followed by the IF (P < .05). Both the LL and SV were more tender than the BF and ST (P < .05). Conversely, the ST and BF had the greatest abundance of connective tissue followed by the SV, the LL, then the IF, with the PM having the least amount of connective tissue (P < .05). The IF and SV had the greatest juiciness compared to all other muscles (P < .05). The LL was juicier compared to the PM and ST (P < .05). The LL and SV had the greatest beef flavor identity intensity compared to all other muscles (P < .05). The BF, IF, and PM had greater beef flavor intensity compared to the ST (P < .05). The LL and PM had greater brown/roasted intensity compared to the BF and ST (P < .05). The SV had the greatest fat-like intensity compared to all other muscles followed by the IF (P < .05). The ST had the lowest fat-like intensity (P < .05). Bloody/serum intensity was greater in the BF compared to the PM and ST (P < .05). Metallic intensity was the greatest in the BF compared to IF, LL, PM, and SV (P < .05). The IF had the greatest liver-like aromatics, followed by the PM (P < .05). Moreover, the BF had greater liver-like intensity compared to the LL and ST (P < .05). The PM had the greatest cardboard-like intensity compared to the BF, IF, LL, and SV (P < .05). The ST and BF were the sourest compared to all other muscles (P < .05).

Conclusion: These data show that muscles within a beef carcass possess varying color stabilities and flavor profiles. The PM, IF, SV, and BF were the most color labile, whereas the LL and ST showed increased color stability. As expected, the PM was the most tender muscle; however, it showed itself to be less oxidatively stable. The SV had the greatest fat-like aromatics, and the IF had the most intense liver-like aromatics. Muscles from the round were the toughest muscles. These quality phenotypes are likely the function of varying muscle fiber types and associated biochemical attributes among selected muscles. Therefore, when aiming to improve beef color or palatability, quality interventions should be muscle specific.

Funding Source: This research was coordinated by the Beef CheckOff, a contractor of the National Cattlemen’s Beef Association.

Keywords: beef, flavor, color, retail, sensory.

65 The Effect of Peanut-Skin Supplemented Diet on Broiler Meat Quality

Afsana Rahaman Munmun^1,2*, Jean Caceres Caceres¹, Christina Sigmon¹, Yabaiz Tahir¹, Thien Vu^1,3, Ondulla Toomer^1,2,3, Lin Walker¹, and Yan Campbell¹, ¹Department of Poultry Science, North Carolina State University, Raleigh, NC 27607, USA, ²Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, NC 27606, USA, ³Agricultural Research Service, US Department of Agriculture, Raleigh, NC 27607, USA *amunmun@ncsu.edu

Introduction/Objectives: In recent decades, substantial progress in animal genetics, nutrition, and production practices has enabled the animal agriculture industry to meet the rising demands of a growing global population and increased consumer preference for high-quality animal protein. This achievement has relied on the inclusion of premium feed ingredients such as wheat, soybeans, and corn. However, the rising demand from both the biofuel industry and human nutrition sectors, alongside crop shortages in various regions, has led to a significant increase in feed costs. Peanut (PN) skins are a plentiful and less expensive PN processing byproduct, yet they offer substantial nutritional value that can enhance animal diets. This study investigated the effects of incorporating 5% ground PN skin in the diet of broiler chickens on various meat quality parameters. The aim was to assess whether PN skin supplementation would impact broiler quality and be a potential alternative dietary supplement for broiler production.

Materials and Methods: A controlled experiment was conducted with 90 broilers (45/treatment, 3 replicate/treatment, 15/replicate). Broilers were fed a 3-phase corn/soy mash diet regimen. Diets were isocaloric and isonitrogenous with the starter providing 3000 kcal/kg and 22% crude protein, the grower providing 3100 kcal/kg and 21% protein, and the finisher providing 3200 kcal/kg and 19% protein. A PN skin-supplemented diet was prepared for half of the broilers by adding 5% ground PN skins to the basal diet at each phase. Five broilers were sampled from each pen (15 birds/treatment) for processing after 6 wk of age. All animal research procedures conducted in these feeding trials were approved by the Institutional Animal Care and Use Committee at North Carolina State University. Measurements were taken for body weight, hot- and chilled-carcass weight after first processing. Carcasses were chilled after 15 min postslaughter, deboned after 2 h of chilling, kept at refrigeration temperature after deboning for 24 h pH, color, and weights. Breasts were frozen for storage after 24 h. The pH measurements of the right breast muscle were taken at 15 min, 2 h, 24 h, and 2.5 mo postmortem using a meat pH meter (Hanna Instruments). Color was assessed on right breasts at 24 h after slaughter and again at 2.5 mo using a colorimeter. The right breast muscle samples were assessed after 2 h postslaughter for the incidence of white striping and woody breast myopathies using a 0 to 3 scoring scale (0 = none, 1 = mild, 2 = moderate, 3 = severe), and for spaghetti meat myopathy using a 0 to 2 scoring scale (0 = normal, 1 = moderate, 2 = severe). Composition analysis (near-infrared spectroscopy), texture analysis (blunt Meullenet-Owens razor shear and Warner-Bratzler shear force), cook loss, and thaw loss were assessed after 2.5 mo of the frozen right breast meat. Texture analysis had been performed on both raw and cooked broiler breasts. All data were analyzed by SAS 9.4 with 1-way analysis of variance and general linear model using Duncan’s new multiple range tests for mean separation with a P value less than .05.

Results: Results indicated that chicken from the PN skin diet exhibited lower body weights compared to the control (2.21 kg vs. 2.49 kg; P < .05). Similarly, hot and chilled carcass and breast weights for the PN skin treatment had lower weights compared to the control (P < .05).There was no difference in pH at 15 min and 24 h for control and PN treatments (P > .05), but pH at 2 h and 2.5 mo was lower in PN treatment compared to the control (P < .05). There was no difference in color and texture between the 2 treatments (P > .05). The fat, moisture, protein, collagen, and ash content of the meat did not vary between the 2 treatments as well. Significantly lower cook loss and thaw loss were observed in the PN skin-based diet compared to the control (cook loss: 21.73% vs. 25.58%, thaw loss: 12.72% vs. 18.74%; P < .05). There was no significant difference in the myopathy incidence between the 2 treatments (P > .05).

Conclusion: In conclusion, 5% PN skin lowered the live body weight, but it did not impact color (at 24 h and 2.5 mo), pH (no difference at 15 min and 24 h, but lowered at 2 h and 2.5 mo in PN treatment), texture (after 2.5 mo), composition (after 2.5 mo), or myopathy incidence of the meat (at 2 h), suggesting that PN skin can be used as a dietary supplement without negatively impacting overall broiler meat quality. Moreover, a significantly lower cook loss and thaw loss in 5% PN skin treatments indicate better water-holding capacity, likely influenced by subtle differences in muscle structure, fat composition, collagen characteristics, or protein stability, despite similar overall meat composition. While additional feeding trials are needed, these results suggest that PN skins may serve as a suitable poultry feed additive.

Funding Source: This research was supported by the US Department of Agriculture’s Agricultural Research Service (USDA-ARS) and the Campbell Protein Technology Laboratory at North Carolina State University. The author acknowledges the USDA-ARS and all the collaborators for live bird samples for this research.

Keywords: broilers, peanut-skin supplemented diet, meat quality.

66 Quality and Consumer Sensory Scores of Tumbled and Aged Beef Brisket Flat and Point Cuts

Emmet Long¹, Derico Setyabrata², and Jacob R. Tuell^1,*, ¹School of Agricultural Sciences, Northwest Missouri State University, Maryville, MO 64468, USA, ²Department of Animal Science, University of Arkansas, Fayetteville, AR 72704, USA *jtuell@nwmissouri.edu

Introduction/Objectives: Beef brisket is inherently tough due to high concentration of intramuscular connective tissues. Tumbling has been demonstrated to disrupt myofibrillar structure and proteolysis during aging of fresh beef; however, its use in conjunction with slow, moist heat cookery has not been fully considered. This study evaluated the application of tumbling and aging of beef brisket flat (M. pectoralis profundus) and point (M. pectoralis superficialis) sections on tenderness and eating quality.

Materials and Methods: Beef briskets (n = 8; US Department of Agriculture choice) were obtained from a commercial processor at 9 d postmortem and separated into flat and point cuts. Each muscle was halved and assigned to 120 min of tumbling at 8.5 rpm in a Promarks TM-150 vacuum tumbler (TRT) or control (CON) in a balanced design. At 10 d postmortem, TRT samples were tumbled, and all sections were aged an additional 14 d at 4°C prior to frozen storage at −20°C. Sections were thawed 40 h, then smoked in a commercial smokehouse to 91°C. Measures of quality included pH, water-holding ability, yield, and Warner-Bratzler shear force (WBSF). A consumer sensory panel (n = 104) was conducted to assess the liking of tenderness, juiciness, flavor, and overall acceptability of each trait, perceived quality, and willingness to pay. The effects of treatment, muscle, and interaction were analyzed using a linear mixed model in R, with endpoint temperature and cooking duration included as covariates where appropriate. Tukey-adjusted post-hoc comparisons were performed for pairwise differences. Pearson correlation coefficients were determined.

Results: At each time point, point cuts had a higher pH than the flat (P < .05). After aging, TRT had lower pH (5.59) than CON (5.63; P < .05), though the pH after thawing was equivalent (P > .05). Flat cuts had higher thawing loss than points (P < .05), and no differences in water holding were found between TRT and CON including yield (P > .05). Points had lower WBSF than flats (P < .05) with no significant treatment effect. Consumers found points to be superior to flats for tenderness, juiciness, flavor, and overall liking (P < .05) with no impact of tumbling treatment or the interaction (P > .05). Acceptability of points was higher than flats for tenderness (97.7% vs. 73.5%), juiciness (88.8% vs. 30.4%), and overall (90.3% vs. 63.6%; P < .05). Consequently, more points were rated as “premium” quality (9.1% vs. 1.0%; P < .05) with greater willingness to pay (P < .05). No significant effects of treatment or interaction were found for any sensory trait. Values for WBSF had a moderate negative correlation with tenderness liking (r = −0.636), juiciness liking (r = −0.496), and overall liking (r = −0.402; P < .05).

Conclusion: The tumbling and aging treatment was not effective at improving tenderness in either flat or point sections cooked with slow, moist heat cookery. Point sections were more tender and scored favorably for all sensory traits relative to flats. This study demonstrates the possibility of marketing brisket points separate from flats to consumers at a premium.

Funding Source: This work was funded by the Northwest Missouri State University Faculty Research Committee and Missouri Beef Industry Council.

Keywords: beef, brisket, sensory, tenderness, WBSF.

67 Effect of Dietary Fats and Stunning Methods on Chicken Meat Quality Attributes and Myopathy Indicators

Shijinaraj Manjankattil^*, Jinquan Wang, Matthew Hughes, Abigail McConnell, Madalyn Jennings, Juan Carlos Figueroa Sorto, Samuel Rochell, and Dianna Bourassa, Department of Poultry Science, Auburn University, Auburn, AL 36849, USA *szr0141@auburn.edu

Introduction/Objectives: Quality attributes such as pH, color, texture, and water loss are key determinants of consumer acceptability and profitability in chicken meat. There is a complex interplay of intrinsic and extrinsic factors regulating muscle development, pigmentation, and physiologic transformations during the conversion of muscle to meat. Modifications in dietary composition during the grow-out phase, combined with appropriate processing methods, can lead to alterations in meat quality. This study evaluated the impact of changes in dietary fats and different stunning methods on the quality attributes and myopathy scores of chicken breast fillets.

Materials and Methods: This study was approved by the Institutional Animal Care and Use Committee at Auburn University (protocol # 2024 5409). A total of 1,128, day-old, Ross 708 male chicks were randomly assigned to 4 dietary treatment groups and 12 replicates each. All birds received a basal diet from days 0 to 3 and switched to 4 experimental diets with the fat source of soy oil (T1), poultry fat (T2), acidulated fat (T3), and palm oil (T4) for a 42-d period. On day 43, birds from each treatment group were processed using either electrical stunning (ES) or controlled atmospheric stunning (CAS) methods. After chilling, carcasses were deboned, and a total of 104 breast fillets were randomly selected from 8 treatment groups (4 dietary source by 2 stunning methods, n = 13) to measure color and pH at both 2 h and 24 h postmortem. L*, a*, and b* values were recorded from 3 different points of the dorsal side of a single breast fillet, and average values were calculated. Additionally, the samples were weighed at 2 h and 24 h postmortem, and drip loss was calculated in percentage. All samples were stored at 4°C until the 24-h measurement. At 24 h postmortem, breast fillet texture properties were analyzed using the blunt Meullenet-Owens razor shear method to measure shear force and energy from 5 different points on each breast sample. A total of 573 breast samples were evaluated for the incidence of woody breast, spaghetti meat, and white striping, with severity scores ranging from 0 to 3 for woody breast and white striping and 0 to 2 for spaghetti meat. Color, pH, drip loss, and shear force measurements were analyzed using the 2-way analysis of variance model in PROC GLM procedure of SAS, with mean separation performed using the honestly significant difference test. Myopathy scoring data were analyzed using the Kruskal-Wallis test in R by kruskal.test() function. χ² test was used to determine the independence of each score of 0, 1, 2 and 3 for dietary fat source and stunning method. Statistical significance was considered at a P value less than or equal to .05.

Results: The pHs of breast fillets were 6.42, 6.39, 6.45, and 6.36 at 2 h and 5.71, 5.79, 5.78, and 5.90 at 24 h of postmortem for T1, T2, T3, and T4, respectively. At 2 h postmortem, breast fillets from the ES group had a pH of 6.47 and were significantly higher than the CAS group of 6.35 (P < .0001), whereas at 24 h, breast fillets from the CAS group had a significantly higher pH of 5.80 compared to the ES group at 5.74 (P = .007). At 2 h postmortem, breast fillets from T4 group had a significantly lower pH of 6.36 compared to T3 of 6.45. Breast fillets from T1 and T2 had a pH of 6.42 and 6.39, respectively, and showed no difference with other 2 groups. A significant interaction between fat treatments and stunning methods was observed at 2 h (P = .036), but no significant interaction was detected at 24 h (P = .1537). No significant differences in L* values of breast meat were observed between dietary treatments and stunning methods at both 2 h and 24 h postmortem. While a* values showed no significant difference at 2 h, higher values of 3.23 and 2.50 were recorded in T1 and T2 groups compared to 1.73 and 1.69 from T3 and T4, respectively, at 24 h. Additionally, the ES group resulted in significantly higher a* value of 2.78 than the CAS group of 1.79 (P < .001). After 24 h, the CAS group had significantly higher b* values with a mean of 9.42 compared to 8.70 observed in the ES group (P = .014). Shear energy values of 70.7, 74.3, 73.5, and 70.8 N/mm were detected for T1, T2, T3, and T4, respectively. The percentage of water loss from meat samples ranged from 2.2% to 2.7% across all treatment groups. No significant differences were attributed to dietary fats or stunning methods in shear energy and drip loss. Breast fillets from the CAS group showed a higher incidence of woody breast compared to the ES group (P < .001). Seventy-nine percent of samples from the ES group received a woody breast score of 0, which is significantly higher than to the breast fillet from the CAS group at 49% (P < .001). In contrast, a higher percentage of score 0 in the CAS group and score 1 in the ES group (P < .01) was observed for spaghetti meat. No significant differences in white striping were detected between stunning methods. However, T2 had a significantly higher percentage of samples classified within score 2 compared to other treatments (P < .016).

Conclusion: The enhanced reddish and yellowish coloration observed in ES-treated samples necessitates further investigation to elucidate potential alterations in muscle pigments and muscle physiology associated with ES. Additionally, dietary fat sources exhibit distinct effects on meat color characteristics, underscoring their role in quality modulation. The increased incidence of white striping in poultry fat-supplemented samples emphasizes the need for targeted dietary interventions to mitigate breast fillet myopathy and its associated economic consequences. Furthermore, strategic modifications in dietary fat composition and processing techniques can substantially influence meat quality, ultimately affecting profitability in the poultry industry.

Funding Source: This work was supported by the US Department of Agriculture (USDA) Agricultural Research Service in Athens, Georgia (project number: 6040-32000-012-006-S), the Alabama Agricultural Experiment Station, and the Hatch Program of the National Institute of Food and Agriculture, USDA.

Keywords: quality fat, myopathy, texture, color.

68 Influence of Endpoint Temperature on Internal Cooked Color and Myoglobin Thermal Stability of Ground Beef Patties

Loise Lima^1,2, Ana Paula Salim^1,*, Runnan Li¹, Gregg Rentfrow¹, Carlos A. Conte-Junior², and Surendranath P. Suman¹, ¹Department of Animal and Food Sciences, University of Kentucky, Lexington, KY 40506, USA, ²Center for Food Analysis, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941598, Brazil *apaulasalim@gmail.com

Introduction/Objectives: Myoglobin denaturation is dependent on its redox state and directly influences the internal color of cooked meat. Premature browning, wherein ground beef appears fully cooked before reaching 71°C, poses a food safety risk because consumers often rely on cooked color to assess doneness. The relationship among endpoint temperature, internal cooked color, and myoglobin thermal stability in ground beef is not clearly understood. This study investigated the effects of endpoint temperature on internal color and myoglobin thermal stability in cooked ground beef patties.

Materials and Methods: Eight (n = 8) coarse ground beef (80% lean) chubs were obtained locally. Each chub was hand-formed into 16 patties (120 g, 10-cm diameter, and 1.5-cm thick). The patties were stored in the dark at 2°C for either 0 d, 2 d, 4 d, or 7 d. After storage and raw color measurement, the patties were cooked to an internal endpoint temperature of 54°C (C54), 63°C (C63), or 72°C (C72). Cooked patties were removed from the grill, cooled, and sliced horizontally prior to internal cooked color measurements. The thermal stability of myoglobin from cooked patties was assessed by differential scanning calorimetry. The denaturation temperature (Tm) and enthalpy (ΔH) were determined. The data were analyzed using XLSTAT software. A 2-way analysis of variance was performed to determine the effects of endpoint cooking temperatures and days of storage on internal cooked color and myoglobin denaturation. Tukey’s test was used to compare treatment means at 5% significance level (P < .05).

Results: The C63 and C72 patties exhibited greater (P < .05) L* values (lightness) than C54 on days 0, 2, 4, and 7 of storage. However, for all the treatments, L* values remained unchanged (P > .05) during 7 d of storage. Increasing endpoint temperature resulted in a progressive decline (P < .05) in a* values (redness) on day 0. However, no differences (P > .05) in a* values were observed between C63 and C72 on day 2 and between C54 and C63 on days 4 and 7. Overall, a* values were not influenced (P > .05) by storage time, regardless of endpoint temperature. Color stability (R630/580) decreased with increasing endpoint temperature (P < .05), except on day 2 where C54 and C63 exhibited similar (P > .05) results. In general, R630/580 remained stable (P > .05) throughout the storage. Internal endpoint temperature influenced the thermal denaturation of myoglobin, as indicated by the temperature maximum (Tm) of the endothermic peaks (P < .05). On day 0, Tm values increased with an increase in endpoint temperature, reflecting a possible thermal unfolding of myoglobin. Storage did not affect Tm (P > .05). Additionally, the ΔH of denaturation did not vary (P > .05) with endpoint temperature or storage.

Conclusion: The results demonstrate that the internal endpoint temperature influenced the color and the thermal stability of myoglobin in cooked ground beef patties. While increased endpoint temperatures decreased internal redness, it increased myoglobin thermal stability. Additional work is necessary to characterize the mechanisms affecting the thermal stability of myoglobin in cooked meat.

Funding Source: This work was supported by the National Institute of Food and Agriculture, US Department of Agriculture, Hatch-Multistate Project 7003954.

Keywords: cooked color, myoglobin denaturation.

69 Effect of Dietary Low-Fat Tenebrio molitor Larvae Meal on Quality Traits of Broiler Breast (Pectoralis Major) Meat

Nikolay Kolev¹*, Desislava Vlahova-Vangelova¹, Desislav Balev¹, Stefan Dragoev¹, Teodora Popova², Evgeni Petkov², Ana Paula Salim³, and Surendranath P. Suman³, ¹Department of Meat and Fish Technology, University of Food Technologies, Plovdiv, Bulgaria, ²Agricultural Academy, Institute of Animal Science, Kostinbrod, Bulgaria, ³Department of Animal and Food Sciences, University of Kentucky, Lexington, KY 40506, USA *n_kolev@uft-plovdiv.bg

Introduction/Objectives: Tenebrio molitor larvae is a high-quality protein source used as a feed ingredient in poultry diets because of its positive effects on growth performance. It offers a superior amino acid profile and serves as a sustainable and non-GMO alternative to soybean meal. At their early developmental stages, the larvae contain higher protein and lower fat levels than those at later stages, making it a suitable ingredient in poultry feed. However, the impact of Tenebrio molitor larvae on broiler meat quality remains unclear. Therefore, we evaluated the effects of low-fat Tenebrio molitor meal (LFTLM) as a replacement for soybean meal on the pH, instrumental color, and texture of broiler breast.

Materials and Methods: The experiment was conducted in accordance with Directive 2010/63/EU, under permit no. 277 issued by the Bulgarian Food Safety Agency. A total of 120 one-day-old male Ross 308 broiler chickens were randomly assigned to 5 dietary treatment groups based on the designated experimental diets. Each treatment group was housed in 4 cages (6 birds per cage), resulting in 4 experimental replicates and a total of 24 birds per dietary treatment. The experimental diets included: a control diet consisting of conventional feed without LFTLM (control) and diets containing 2.5% (T2.5), 5.0% (T5.0), 7.5% (T7.5), and 10.0% (T10.0) LFTLM as a partial replacement for soybean meal control feed. The feeding duration was divided into 2 phases: (1) starter phase (days 1–14) and (2) grower phase (days 15–35), during which the birds were fed experimental diets. At the end of the grower phase, birds were slaughtered humanely. Twenty-four hours postmortem, pH, instrumental lightness (L*), redness (a*), yellowness (b*), and texture profile were assessed on the breast (pectoralis major) muscles of each carcass. Statistical analysis was performed using the PROC GLIMMIX procedure in SAS. Least-squares means were compared using the PDIFF option with a Tukey-Kramer adjustment, and differences were considered statistically significant at P < 0.05.

Results: The pH of broiler breasts from the control exhibited greater (P < 0.05) values than their counterparts, whereas T10.0 exhibited the lowest (P < 0.05) pH values. T2.5 breasts exhibited a decrease (P < 0.05) in L* compared with the control, although similar (P > 0.05) L* were observed among other LFTLM treatments. There was an increase (P < 0.05) in a* in the breasts of broilers fed LFTLM compared with the control. The inclusion of LFTLM in broilers’ diets did not (P > 0.05) affect the b* values of breasts. The inclusion of 2.5% of LFTLM (T2.5) increased (P < 0.05) breast cohesiveness and chewiness compared with the control. No differences (P > 0.05) in cohesiveness and chewiness were observed among T5.0, T7.5, and T10.0 treatments.

Conclusion: These findings suggest that the inclusion of LFTLM in broiler diets increased redness without compromising the lightness and texture of broiler breasts. LFTLM can be utilized as a sustainable alternative to soybean meal in poultry feed, with minimal adverse effects on meat quality.

Funding Source: This research was funded by the Bulgarian National Science Fund of the Ministry of Education and Science in Bulgaria (grant number KP-06-N76/7, December 5, 2023).

Keywords: broiler, meat quality, insect-based feed.

70 Evaluating Impact of Computed Tomography Slice Thickness on Tissue Segmentation Capabilities

Reese A. Wilson*, Andres Mendizabal, Harshit Parmar, Chris Monico, Blake A. Foraker, Markus F. Miller, and Dale R. Woerner, Texas Tech University, Lubbock, TX 79409, USA *reese.wilson@ttu.edu

Introduction/Objectives: Computed tomography (CT) is a valuable technique for evaluating beef composition, as it provides a nondestructive means of assessing the volumetric distribution of different tissues. CT scanning allows for the measurement of various tissues, including fat, muscle, connective tissue, and bone, without the need for physical dissection. CT scanning functions by capturing detailed cross-sectional images of the carcass. These images are analyzed through segmentation processes to isolate different tissue types, and the resulting volumes are subsequently converted into weight measurements using established density values for each tissue. The objective of this study was to evaluate the effect of slice thickness on overall mask volume creation and the percentage of the mask utilized for tissue segmentation.

Materials and Methods: Ten beef rounds (N = 10) were collected from a commercial packing plant. These rounds were specifically selected to represent varying levels of muscling and fatness. Approximately 24 h after collection, the rounds were scanned using CT at the Texas Tech University School of Veterinary Medicine. Repeated scans were performed under the “abdomen pelvis” protocol with a slice thickness of 1 mm, and images were recorded in a 32-bit format. Additional DICOM files were generated to simulate thicker slices of 2 mm, 4 mm, and 8 mm, which were then converted to NIFTI files. Morphological operations were used to create a mask separating the background from the region of interest: the round. Each segmented region, including marrow, trabecular bone, and cortical bone, was saved individually as a separate NIFTI file, with detailed metadata outlining the segmentation steps. Twenty-four hours after CT imaging, the beef rounds were commercially fabricated. The weights of bones, after the removal of any remaining lean tissue, fat, or connective tissue, were recorded to the nearest 0.022 lb. Femur and tibia bones were split in half, and yellow marrow was separated, bagged, and weighed to the nearest 0.0022 lb. Bone tissue weight estimation was conducted using 4 approaches. The “1-way marrow excluded” method considered only voxels above the bone threshold, multiplying their volume by 2.2 kg/L. The “1-way segmentation” approach included the entire mask volume, also using 2.2 kg/L. The “2-way” method differentiated between cortical and trabecular bone, multiplying their respective volumes by 2.2 kg/L and 1 kg/L before summing the weights. The “3-way differentiation” approach separately calculated marrow (0.4 kg/L), cortical bone (2.2 kg/L), and trabecular bone (1 kg/L), summing all 3 to estimate total bone weight. Linear regression analyses were performed with slice thickness as a fixed effect. The estimated bone weights obtained using different methods were compared with actual bone dissection weights. Mean absolute error and root mean square error were calculated for each method and slice thickness to assess measurement accuracy and the impact of slice thickness on error.

Results: Based upon the linear regression results, for every 1-mm increase in slice thickness, the total mask volume increases by an average of 0.03 L. This increase occurs because as voxel size increases in length, the voxel value is averaged across a longer section of the scan. This averaging introduces more error, particularly near the periphery of the object where voxel values are closer to −1000 Hounsfield units (HU), the typical CT value for air, which represents empty space. Although this increase in mask volume is relatively small, the effect on the percentage of the mask that is accurately segmented is more pronounced. For every 1-mm increase in slice thickness, the percentage of the segmented mask decreases by approximately 0.3%. Because voxel values decrease as more air is included in the voxel, it is essential to establish this lower threshold to ensure that segmented fat voxels are primarily fat and not air. A similar effect may occur with muscle tissue. For example, in imaging a muscle without fat, it may still appear to have a thin layer of fat on its surface because of how voxel values are calculated. When a voxel near the muscle boundary contains more air than lean tissue, its value will resemble that of fat. Without a proper lower threshold for fat, these low-value voxels would be incorrectly identified as fat, artificially increasing the measured fat volume. Accurate weight estimation using CT-derived volumes with fixed densities is challenging. The “1-way segmentation” method, wherein the entire mask volume is multiplied by 2.2 kg/L, resulted in the largest error, overestimating bone weight by an average of 12 to 13 lb. The “1-way marrow excluded” method, which excludes marrow from the mask volume, produced lower errors but still overestimated bone weight by 10 to 12 lb. The third approach, which excludes marrow but further segments the bone into trabecular and cortical components, demonstrated an average error of approximately 2.4 to 2.9 lb. Surprisingly, this error was smaller than the approach that included marrow, which had an average error of 2.5 to 3 lb. A trend emerged: Methods that did not differentiate bone types had higher errors and consistently overestimated bone weight. The slightly higher error observed when marrow was included is likely because adding marrow contributed additional weight to the estimation, amplifying the effect of overestimation.

Conclusion: The effect of slice thickness on overall mask volume creation and the percentage of the mask utilized for tissue segmentation varied by method. When bone was not differentiated into trabecular and cortical regions, thicker slice thicknesses resulted in less error. This occurred because, as slice thickness increased, the total bone mask volume decreased, reducing the extent of overestimation. Conversely, when bone was segmented into trabecular and cortical regions, thinner slice thicknesses produced smaller errors because of improved precision. Additionally, thicker slices tended to have higher average voxel values, influenced by the high HU values of cortical bone, which increased the proportion of cortical bone in the estimate and further amplified overestimation.

Funding Source: The project was funded by the National Cattlemen’s Beef Association (NCBA).

Keywords: beef, machine learning, CT, yield.

71 Effects of Cortisol Levels in Angus-Cross Steers on Carcass Characteristics, Lean Color, and Steak Palatability

Megan V. Sorenson¹*, Luclia C. Gracia¹, Muyem E. Fatola¹, Ben J. Renquist¹, Duane M. Wulf¹, Reinaldo F. Cooke², and Tanner J. Machado³, ¹Animal and Comparative Biomedical Science, University of Arizona, Tucson, AZ 85721, USA ²Department of Animal Science, Texas A&M University, College Station, TX 77843, USA ³Department of Animal Science and Veterinary Technology, Texas A&M University-Kingsville, Kingsville, TX 78363, USA *meganvsorenson@arizona.edu

Introduction/Objectives: The objective of this study is to determine the relationship of cortisol levels with carcass characteristics, lean color, and steak palatability.

Materials and Methods: Angus-cross steers (n = 104) were purchased in Tennessee and transported to McGregor, Texas, for growing and finishing. Hair samples were collected on days 0, 14, 28, 42, and 60; blood samples were collected on days 178 (prior to 5-h transportation to packing plant) and 179 (at exsanguination); and cortisol levels were determined on all samples. Following harvest, hot carcass weight was collected, and carcasses were chilled for 36 h. Following chilling, carcass data were collected (adjusted fat thickness, ribeye area, marbling score, skeletal maturity, lean maturity, and L*a*b* colorimeter readings). Longissimus lumborum samples (n = 208; 2 from each carcass, right and left) were excised for further analysis. Longissimus lumborum samples were assays forglycogen, glucose, glucose-6-phosphate, and lactate to calculate glycolytic potential. On day 7 postmortem, ultimate pH was determined, and 2.5-cm-thick steaks (2 per carcass) were frozen. Steaks were thawed for 24 h and then cooked to 69°C for slice shear force (SSF), Warner-Bratzler shear force (WBSF), and trained sensory panel analysis. Sensory panelists evaluated juiciness, tenderness, and beef flavor intensity and were trained according to the American Meat Science Association standards. Correlation coefficients were calculated among cortisol levels at various sampling times and with carcass and meat quality variables.

Results: Correlations (r = +0.43 to +0.48) existed among hair cortisol levels at days 0, 14, and 28 (P < 0.05). Hair cortisol on day 42 was correlated (r = +0.33) with hair cortisol on day 60 (P < 0.05). Blood cortisol prior to transportation (day 178) was correlated (r = +0.52) with blood cortisol at exsanguination (day 179, P < 0.05). Cortisol levels were not correlated with glycolytic factors or ultimate pH (P > 0.05). Blood cortisol levels at harvest (average of days 178 and 179) were positively correlated with SSF (r = +0.27) and WBSF (r = +0.23) values (P < 0.05) but were not correlated with sensory panel ratings (P > 0.05).

Conclusion: Cattle with high cortisol levels in the early stages of the feeding period did not maintain those elevated levels throughout the remainder of the feeding period. Cortisol levels were not related to muscle glycogen levels or postmortem glucose metabolism. Higher cortisol levels at harvest were associated with tougher meat (higher SSF and WBSF values).

Funding Source: University of Arizona.

Keywords: cortisol, beef, quality, color, palatability.

72 Extended Beef Wet-Aging Influences on Biceps Femoris, Gluteus Medius and Semimembranosus Palatability and Objective Raw Color Measurements

Amelia J. Main¹*, M. Sebastian Hernandez¹, Jerrad F. Legako¹, Rhonda K. Miller², and Dale R. Woerner², ¹Texas Tech University, Lubbock, TX 79409, USA, ²Texas A&M University, College Station, TX 77840, USA *awyle@ttu.edu

Introduction/Objectives: Postmortem wet aging is a common industry practice to enhance beef tenderness and palatability through proteolytic enzyme activity. Although this process is well documented for improving tenderness, especially in middle meats like the longissimus lumborum, its impact on flavor, particularly off-flavor development, during extended aging is less understood. As flavor remains a key driver of consumer satisfaction, there is a growing need to assess how aging influences palatability in beef cuts. Muscles such as the biceps femoris (BF), gluteus medius (GM), and semimembranosus (SM) differ in biochemical composition, which may result in unique aging responses not yet fully characterized. The objective of this study was to characterize the influence of wet-aging duration on BF, GM, and SM muscles by evaluating descriptive sensory attributes and raw color measurements. Results from this study aim to inform quality strategies for extended aging across diverse beef muscles.

Materials and Methods: Eighty beef carcasses of similar marbling score (modest marbling, 500–599), were selected from a commercial facility in West Texas. Paired top sirloin butt (Institutional Meat Purchase Specifications [IMPS] #184) and 1 inside round (IMPS #168) subprimals were collected across 2 trips and transported (0–4°C) to the Gordon W. Davis Meat Laboratory at Texas Tech University. Carcasses were randomly assigned to 1 of 8 aging durations (14, 28, 35, 42, 49, 56, 63, or 70 d; n = 10/duration), and subprimals were aged at 2.2°C ± 0.02°C in darkness. After aging, trained personnel fabricated top sirloin butts into BF and GM muscles and inside rounds into SM muscles. Muscles were sliced into 2.54-cm steaks for sensory analysis and color evaluation. Steaks for sensory analysis were vacuum-sealed and frozen at −80°C, whereas raw samples bloomed for 30 min before instrumental color measurement. Descriptive sensory analysis followed American Meat Science Association (2016) and Adhikari et al. (2011) protocols. Panelists completed 30 h of training and 4 validation sessions. Each muscle was evaluated separately in 10 sessions (8 samples/session) by 6 trained panelists using a 16-point scale. Steaks were thawed (24 h, 4°C), cooked to 71°C, trimmed, cubed (1.3 × 1.3 × thickness), and served under red lighting. Instrumental color was measured using a HunterLab MiniScan spectrophotometer (illuminant A, 10° observer angle). CIE L*, a*, and b* values were averaged to calculate hue and chroma. Values were converted to XYZ and RGB to visualize color changes over aging. Sensory and color data were analyzed in R (version 4.3.1) with α = 0.05. Analysis of variance models included aging duration (fixed effect) and collection date (random effect). Estimated marginal means were calculated using the lme4 package and tested with Tukey-adjusted pairwise comparisons (emmeans package). Principal coordinate analysis (PCoA) visualized sensory data using Bray-Curtis distances (vegan package) and PCoA (ape package), with points colored by aging duration. Biplot vectors showed covariance between dimensions and sensory attributes. Partial least-squares discriminant analysis (PLS-DA) (caret package) identified groupings, with ellipses colored by muscle.

Results: Descriptive sensory analysis revealed aging duration influenced flavor profiles across the BF, GM, and SM muscles. In BF, muscle fiber tenderness, juiciness, and several flavor attributes remained consistent across aging durations (P ≥ 0.08). However, beef flavor identity decreased at 70 d (P = 0.01), and buttery flavor was decreased at 63 and 70 d compared with 28 d (P < 0.01). Off-flavors such as liver-like, musty/earthy, cardboardy, and bitter increased with aging, particularly at 63 and 70 d (P < 0.01). Sour basic taste also intensified with longer aging duration, whereas sweet and umami declined (P < 0.02). In GM, aging duration influenced tenderness and connective tissue attributes (P < 0.01), with greater tenderness and lower connective tissue noted at 63 d. Beef flavor identity and umami both declined with aging (P < 0.01), especially at 63 d. Metallic, liver-like, bitter, sour, musty/earthy, cardboardy, and painty off-flavors all increased with extended aging durations (P < 0.01). In contrast, most sensory traits in the SM muscle, including tenderness, juiciness, and positive flavor attributes, were unaffected by aging (P ≥ 0.07). Cardboardy and bitter attributes showed slight increases with aging duration (P < 0.02) but remained barely detectable. Principal coordinate analysis and PLS-DA revealed distinct clustering among the 3 muscles, demonstrating unique sensory profiles. The BF clustered separately from GM and SM, which showed some overlap but remained distinguishable, confirming muscle-specific flavor differences. Instrumental objective color results supported these trends. In BF, a* (redness) decreased with aging duration (P = 0.05), whereas L*, b*, hue, and chroma were unaffected. GM showed decreased a* and b* values at longer aging durations (P < 0.03), indicating reduced redness and yellowness. SM exhibited declines in L*, a*, b*, and chroma at later aging stages (P < 0.01), reflecting diminished lightness and color intensity over time.

Conclusion: This study demonstrated that extended wet aging alters the flavor profile of beef muscles, with notable increases in off-flavor attributes and decreases in positive flavor notes, such as beef identity and umami. These effects were consistent across the BF, GM, and SM muscles, although the sensory changes were evaluated individually by muscle type. Raw instrumental color measurements showed minimal but consistent reductions in redness with longer aging durations. These findings underscore the importance of carefully managing postmortem aging to balance flavor development, shelf life, and consumer acceptance. A targeted approach to aging may help optimize beef quality, guiding producers, processors, and retailers in decision-making for value-added beef programs and extended storage applications.

Funding Source: Research was coordinated by the National Cattlemen’s Beef Association.

Keywords: beef, descriptive sensory, instrumental color.

73 Exploring Dry Aging as a Value-Adding Method for Bison Meat Quality Enhancement

Evie Sierra¹*, Dong-Jin Shin¹, Amanda Weaver², Kyle Grubbs², and Yuan H. Brad Kim¹, ¹Purdue University, West Lafayette, IN 47907, USA, ²South Dakota State University, Brookings, SD 57007, USA *elsierra@purdue.edu

Introduction/Objectives: In recent years, demand for bison meat has grown, driven by its superior nutritional profile compared with beef. Compared with beef, bison meat contains less fat and sodium as well as higher iron contents. Despite its distinct flavor, previous sensory analyses have associated bison meat with off-flavors, such as “gamey” and “metallic.” Dry aging, a value-adding process, is known to enhance flavor complexity and improve other palatability attributes. However, its potential to complement nutritional benefits while enhancing palatability attributes has not been explored in bison loins. Therefore, the objective of this study was to investigate the impacts of various dry-aging methods on meat quality, chemical attributes, and sensory characteristics of bison loins.

Materials and Methods: Paired bone-in striploins (M. longissimus lumborum) were obtained from grain-finished bison carcasses (n = 30) at 7 d postmortem. From the 2 pairs of loins, each loin was randomly assigned to 1 of 4 aging treatments: wet aging (WA), dry aging (DA), dry aging under ultraviolet light (UDA), and dry aging in a plastic bag (DWA; Dry-Aging Bags Brisket/Bone-in, UMAi Dry, Minneapolis, MN). The loins were aged for 28 d in an environment-controlled cooler at 1°C with humidity (65%) and air flow (0.8 m/s). Upon aging, the loins were deboned, trimmed out, and weighed for the final yield estimation. Then, loins were cut into steaks for color stability, pH, Warner-Bratzler shear force, cook loss, myofibrillar fragmentation index (MFI), thiobarbituric acid reactive substance, proximate composition, fatty acid composition, and sensory (consumer [n = 120] and trained [n = 7]) panel evaluations. The experimental design consisted of an incomplete balanced block design, and a PROC GLIMMIX procedure of SAS was utilized (significance level P < 0.05).

Results: WA had the greatest total yield, followed by DWA, whereas DA and UDA had the lowest yields among all treatments (P < 0.05). Moisture content was higher in WA compared with UDA and DA (P < 0.05), with DWA having similar moisture amount to WA (P > 0.05). Protein content was lowest in WA compared with all dry-aged treatments (P < 0.05). WA had higher redness, yellowness, lightness, and chroma values compared with dry-aged treatments throughout display time (P < 0.05). No significant differences were observed among treatments in pH, cook loss, shear force, MFI, or lipid oxidation. The consumer sensory panel found flavor-liking highest in UDA samples compared with WA and DWA samples (P < 0.05), although DA flavor-liking was not significantly different compared with other treatments. Overall liking was detected higher in UDA compared with DWA (P < 0.05), with no differences found in DA and WA compared with other treatments (P > 0.05). In the trained sensory panel, umami flavor was found to be higher in DA samples compared with WA (P < 0.05), with no significant differences found in UDA and DWA compared with other treatments. Greater bloody flavor was detected in WA samples compared with DWA (P < 0.05), and neither UDA nor DA differed from the other treatments (P > 0.05). Juiciness was highest in UDA (P < 0.05), followed by WA and DWA, although these treatments did not differ significantly with other treatments.

Conclusion: The results of this study demonstrate the efficacy of dry aging in flavor enhancement of bison meat with minimal negative effects on other meat quality attributes. The use of a wet-permeable bag effectively mitigated moisture loss, as DWA samples retained higher moisture content and greater yield compared with other dry-aging treatments. Although dry aging reduced total yield compared with wet aging, consumer sensory results indicated improved flavor and overall-liking. Trained sensory evaluation showed further improvements in flavor with dry aging, given higher umami and lower bloody flavor was detected in dry-aged treatments compared with wet aging. Therefore, dry aging can serve as a natural postharvest value-adding process to improve bison meat flavor and consumer acceptance without compromising key quality attributes.

Funding Source: Center of Excellence for Bison Studies.

Keywords: bison, dry aging, flavor, meat quality.

74 Impact of Marbling on Consumer Perception of Palatability and Eating Satisfaction

Blake A. Foraker^*, Markus F. Miller, and Dale R. Woerner, Texas Tech University, Lubbock, TX 79409, USA *blake.foraker@ttu.edu

Introduction/Objectives: Wagyu cattle were first introduced in the United States in 1973, and since then, their popularity has grown substantially. Consumers perceive Wagyu as a niche, high-quality beef product that offers a satisfactory eating experience. Numerous studies have noted this more desirable eating quality is due to extensive intramuscular fat deposition and a unique fatty acid composition, which are characteristics of the breed. The objective of this study was to evaluate the effect of increases in marbling on the probability of a desirable eating experience in Wagyu strip steaks.

Materials and Methods: Wagyu carcass sides used in the study were selected at a beef harvest facility in Washington (N = 116) following a standard 48-h chill period. Carcass sides were selected based on marbling scores obtained from the grading camera and were designated to 8 marbling score groups: 750, 800, 850, 950, 1000, 1050, 1100, and 1150. After carcass selection, 3 steaks were obtained from the striploin of each carcass side (n = 348). Upon packaging and freezing, samples were shipped to Texas Tech University and held in cold storage until use. Each of the 3 steaks were allocated to either chemical fat extraction, sensory analysis, or best-worst panel analysis. Steaks allocated for chemical fat analysis were evaluated using the chloroform methanol fat extraction method. Steaks utilized for sensory analysis were cooked to a peak internal temperature of 71°C in a Rational combi oven. Ten steaks were served to 6 panelists during each panel session. Panelists evaluated each sample for tenderness, juiciness, beefy/brothy, browned/roasted, charred/bitter, fat like, buttery, umami, earthy/mushroom, metallic, liver like, and sour, utilizing a 15-point scale. Steaks allocated for best-worst panel analysis were served to untrained panelists made up of students attending the Culinary Institute of America San Antonio under the same cooking protocol followed for sensory analysis. Panelists were served samples in 9 separate rounds. In each of the first 8 rounds, panelists were served 4 random samples from the 8 different marbling score groups, with each round containing a unique random combination of the marbling score groups. Each panelist was then prompted to identify one sample as the best and one as the worst for each round. For the ninth round, panelists were served 8 samples representing steaks from each of the 8 marbling score groups and asked to rank them from best to worst. The binary outcomes of a “best” and “worst” rating were analyzed using a mixed-effects logistic regression model, with a type III analysis of variance used to evaluate the significance of marbling score on the model. Pairwise comparisons of the marbling score groups were conducted with a Kenward-Roger adjustment and a significance level of α = 0.05.

Results: Marbling score groups showed differences in chemical fat percentage, wherein increases in marbling score resulted in increased chemical fat percentage (P < 0.001). Moreover, pairwise comparisons showed that steaks within the 1150, 1100, and 1050 marbling score groups were different when compared with steaks within the 750, 800, and 850 marbling score groups (P < 0.001). Descriptive sensory analysis revealed that marbling score influenced flavor profiles in Wagyu strip steaks. Tenderness, juiciness, fat like, and buttery flavor attributes showed a general increase as marbling score increased (P < 0.001). Increases in marbling scores were associated with increased tenderness, juiciness, buttery, and fat like flavors (P < 0.05). Furthermore, liver like and charred/bitter flavor attributes exhibited a general decrease in intensity as marbling score increased (P ≤ 0.02). Moreover, beefy/brothy and browned/roasted flavor intensities numerically increased with increases in marbling score; however, they show no differences across marbling score groups (P ≥ 0.077). Umami, earthy/mushroom, metallic, and sour flavor attributes revealed no intensity differences in response to differences in marbling score (P > 0.178). Best-worst panel analysis exhibited differences in the probability of a best and worst placement of Wagyu strip steaks. The probability of a best placement was revealed to generally increase with increases in marbling score (P < 0.05). Steaks within the 1150 marbling score group were found to have the greatest differences from steaks within the 850, 800, and 750 marbling score groups and, therefore, an increased likelihood of a best placement (P < 0.001). The probability of a worst placement was found to numerically decrease with increases in marbling score (P < 0.05). Steaks within the 750 marbling score group were found to have the greatest probability of a worst placement and exhibited the greatest differences from steaks in the remaining marbling score groups (P < 0.001).

Conclusion: This study revealed that increases in marbling score were found to enhance desirable beef flavor attributes, such as tenderness, juiciness, fat like, and buttery, within Wagyu strip steaks. Additionally, more undesirable flavor attributes were found to decrease with increases in marbling score. Higher marbling scores were associated with an increase in the probability of a best placement and a decrease in the probability of a worst placement. This highlights the importance of marbling in enhancing both the sensory experience and the perceived quality of beef.

Funding Source: Funding for this project was provided by AgriBeef Co.

Keywords: beef, consumer, sensory, marbling, Wagyu.

75 Evaluation of the Relationship Between Cattle Age and Tongue Tenderness, Color Life, Intramuscular Fat Content, and Palatability Outcomes

Kade E. Lawrence*, Trent E. Schwartz, Loni W. Lucherk, and Ty E. Lawrence, West Texas A&M University, Canyon, TX 79016, USA *kelawrence1@buffs.wtamu.edu

Introduction/Objectives: American beef tongue is of particular importance to Japanese cuisine and culture, making up a significant portion of US exports to Japan for the past several decades. When making purchasing decisions, Japanese customers prioritize expected palatability and retail color appearance. In the US beef grading system, the maturity of beef cattle is determined using dentition and a combination of skeletal and lean maturity. Age is often used in beef grading systems as an indicator of palatability, particularly tenderness. However, little consideration has been given to the effect of maturity on the palatability of beef variety meats, such as tongue. Therefore, our objective was to begin to understand the relationship of animal age and location within the tongue (root or body) upon the tenderness, color life, intramuscular fat percentage, and palatability outcomes of beef tongue slices.

Materials and Methods: Tongues (n = 60) were procured at a commercial beef processor from cull dairy cow carcasses initially identified at harvest as exhibiting an ear tag displaying a date of birth and 2, 4, 6, or 8 permanent incisors (PI; n = 15 per PI category). Tongues were frozen at the harvest facility, transported to the West Texas A&M University meat laboratory, and thawed for 24 h. Tongues were separated into root and body sections at the lingual fossa, with 1 cm removed on either side of the concave area to provide a distinct separation between the root and body portions. Each portion was sliced transversely into 5-mm-thick samples, trimmed to remove the rough outer epithelial surface tissue, and allocated to uncooked or cooked Allo-Kramer shear force (AKSF), simulated retail display, intramuscular fat (IMF) determination, or trained sensory evaluations. Samples for cooked AKSF were prepared on a clam-shell-style grill press to an internal temperature of 71.1°C; samples from the root and body were cooked for 40 and 35 s, respectively. One slice each from the root and body were placed in overwrap packaging for 108 h of simulated retail display at 2.2°C and evaluated for objective color parameters (L* a* b*). One slice each from the root and body was frozen via liquid nitrogen, powdered, and analyzed using ether extraction to quantify percentage IMF. Five to 7 slices each from root and body portions were evaluated for 9 palatability factors (initial tenderness, sustained tenderness, overall juiciness, springy/gumminess, beef flavor identity, beef flavor intensity, liver-like flavor, bloody/serumy flavor, fat-like flavor) by trained sensory panelists. Data were analyzed using a split-plot experimental design and a 1-way treatment structure with mixed analysis of variance models; number of PI was the fixed effect, and harvest date was the random effect.

Results: Tongues from cull cows with 2 PI were lighter in weight (P < 0.001) and shorter in length (P < 0.001) than those from cows with 4, 6, or 8 PI. Uncooked AKSF did not differ (P = 0.943) between PI categories; however, root portion had 56% lower (P < 0.001) AKSF values than body portion. Cooked AKSF values from cows with 8 PI were 13% higher (P = 0.021) than those from cows with 2 or 4 PI. Cooked AKSF of root portion was 47% lower (P < 0.001) than that of body portion. Cook loss was greater for root portion than body portion (P = 0.001), yet no difference (P = 0.324) in cook loss was detected among number of PI. During simulated retail display, an interaction for L* occurred for PI × location (P < 0.001); root portion slices had higher L* values than those from the body portion, and as cow age increased from 2 to 8 PI, root portion became darker, whereas body portion did not change. During the 108-h simulated display, L* of tongue slices increased (P < 0.001) slightly from 42 to 44. An interaction for a* occurred for PI × location (P < 0.001); slices from the body were redder than slices from the root, and as cow age increased past 4 PI, body portion retained higher a* values than root portion. Intramuscular fat content was strongly associated with location (P < 0.001); slices from the root portion had a 15 percentage point–higher IMF value than body portion slices; however, IMF content was unaffected (P = 0.310) by number of PI. In a trained sensory panel, root samples had higher initial (P < 0.001) and sustained (P < 0.001) tenderness than body samples while being juicier (P < 0.001) and having a greater fat-like flavor (P < 0.001). Moreover, root samples possessed less (P < 0.001) liver-like and bloody/serumy flavors. Body samples were less springy/gummy (P < 0.001) than root samples and had greater beef flavor identity (P = 0.003), yet no difference was detected between root and body samples for beef flavor intensity (P = 0.843). Additionally, initial and sustained tenderness decreased (P = 0.002) as number of PI increased; however, no difference (P ≥ 0.236) was detected across number of PI for the remaining palatability factors.

Conclusion: These results suggest that dentition at harvest can be used as a predictor of tenderness of cooked tongue slices from the root location. Tougher cooked slices from the root were associated with greater number of PI. However, uncooked tenderness values did not differ among dentition classifications. Additionally, these findings suggest that the association of dentition and tongue color life should be further investigated. Slices from the body were redder in color than slices from the root, which can be primarily attributed to fat content of the root. Likewise, slices from the root contained a higher percentage of intramuscular fat than slices from the body, yet no difference was detected among dentition categories. Root portion slices excelled in sensory tenderness and juiciness as well as fat-like flavors, whereas body portion slices had greater beef flavor identity and were less springy/gummy. Overall, subjective tenderness decreased as dentition increased.

Funding Source: Funded by the West Texas A&M University Beef Carcass Research Center.

Keywords: Allo-Kramer, beef, lingua, sensory, dentition.

76 Carcass Fabrication Yield Outcomes of Purebred Angus and Angus × Holstein Crossbred Steers

Thomas C. Petit*, Trent E. Schwartz, Loni W. Lucherk, and Ty E. Lawrence, West Texas A&M University, Canyon, TX 79016, USA *tpetit@wtamu.edu

Introduction/Objectives: Purebred dairy cattle are typically discounted when marketed to beef processors because of unfavorable carcass muscling attributes, ergonomic carcass length complications, and marketing limitations. Dairy-crossbred cattle allow producers to add value to the dairy industry by providing a product that reduces discounts and improves marketability. Angus (A) and Angus × Holstein (AH) cattle differ in genetic composition and in muscular conformation, potentially impacting their yield outcomes for primal and subprimal cuts. Our objective was to determine primal and subprimal yield of black A and black AH steers.

Materials and Methods: Cattle (n = 40) comprised of black A steers (n = 20) and black AH steers (n = 20) originating from 4 different feedlots were harvested on 4 different harvest days at the Caviness Meat Science & Innovation Center. Carcasses were allowed a 48-h chill, and all right sides were ribbed at the 12th and 13th rib interface prior to fabrication and evaluated for yield and quality outcomes. After grading, sides were weighed and then separated into primals. Primals were weighed and fabricated into subprimals according to Institutional Meat Purchase Specifications (IMPS). Subprimal cuts from the brisket included the brisket, deckle off, boneless (IMPS #120). Chuck and foreshank subprimal cuts included the shoulder clod, arm roast (IMPS #114E); top blade, roast (IMPS #114D); shoulder tender (IMPS #114F); chuck tender (IMPS #116B); chuck roll (IMPS #116A); chuck flap (IMPS #116G, PSO 1); short ribs, boneless (IMPS #130A); and pectoral meat (IMPS #115D). Rib subprimal cuts included ribeye roll, lip-on (IMPS #112A), back ribs (IMPS #124), and blade meat (IMPS #109B). Subprimals for the plate were inside skirt (IMPS #121D), outside skirt (IMPS #121C), and plate short ribs, trimmed (IMPS #123A). Loin and sirloin subprimals were striploin, boneless (IMPS #180); tenderloin, full, side muscle on, defatted (IMPS #189A); top sirloin butt, boneless (IMPS #184); bottom sirloin butt, tri-tip, boneless, defatted (IMPS #185D); hanging tender (IMPS #140); and the bottom sirloin butt, ball tip, boneless (IMPS 185B). Subprimal cuts from the flank included flank steak (IMPS #193) and bottom sirloin butt, flap, boneless (IMPS #185A). Round subprimal cuts included knuckle, peeled (IMPS #167A); top (inside) (IMPS #169); outside round (IMPS #171B); eye of round (IMPS #171C); and heel meat (IMPS #171F). Weights of all subprimal cuts, trim, fat, and bones were recorded for each primal. All trim, fat, and bone from all primals were combined to calculate total weights for each category. Yield weights were converted to percentage of chilled carcass weight prior to analysis. Data were analyzed using mixed models; the fixed effect was breed type, and the random effect was feedlot source.

Results: Grading outcomes revealed that A carcasses had greater marbling (P = 0.039; A = 527, AH = 474) and less kidney pelvic heart fat (P < 0.001; A = 3.12%, AH = 3.81%) than AH carcasses. Fat thickness tended to be greater (P = 0.104) and lean maturity scores tended (P = 0.077) to be lower for A compared with AH carcasses. No differences (P ≥ 0.44) were observed between cattle types for ribeye area, yield grade, and bone maturity score. Carcasses of AH cattle were 7.0% heavier (P < 0.01) than those of A cattle. Similarly, AH primals were heavier (P ≤ 0.05) for chuck and foreshank (+9.1%), rib (+6.7%), plate (+9.2%), flank (+8.3%), and round (+8.2%) but not brisket (P = 0.485) or loin (P = 0.203) compared with those in A carcasses. When expressed as a percentage of carcass weight, the loin primal tended (P = 0.075) to be greater for A (15.83%) than AH (15.32%) carcasses; no difference (P ≥ 0.160) in percentage of carcass was detected for remaining primals. Round subprimals did not differ (P ≥ 0.120) as a percentage of the carcass. The striploin of A cattle was a greater percentage of the carcass than AH cattle (A = 2.62%, AH = 2.50%; P = 0.050); no other differences (P ≥ 0.229) in loin subprimal yields were detected. Backribs of AH cattle were a greater percentage of the carcass than A cattle (AH = 0.92%, A = 0.86%; P = 0.029); no other differences (P ≥ 0.580) in rib subprimal yields were observed. Carcasses from A cattle had a greater percentage of boneless chuck short ribs (0.81% vs. 0.73%; P = 0.032) than AH cattle; no other differences existed (P ≥ 0.158) for chuck subprimals. Brisket subprimals from A cattle tended to account for a higher percentage of the carcass than AH cattle (3.83% vs. 3.58%; P = 0.065). In contrast, flank steaks of carcasses from AH cattle were a greater percentage of the carcass (0.51% vs. 0.46%; P = 0.006) than from carcasses of A cattle. No differences were detected for remaining subprimals cut from brisket, plate, or flank primals. No difference in fat trim (P = 0.377), 80/20 trim (P = 0.421), or 50/50 trim (P = 0.211) compiled from all primals was detected. However, bone compiled from all primals accounted for a higher (P < 0.01) percentage of AH carcasses (14.52%) compared with A carcasses (13.07%).

Conclusion: Results from this study suggest that AH carcasses are likely larger in weight at harvest than A carcasses. Grading outcomes revealed that A carcasses had higher marbling scores and less kidney, pelvic, and heart fat than AH carcasses. Increased bone weight of AH carcasses contributed 35% of the difference observed in chilled carcass weight between A and AH carcasses. Few differences in primal or subprimal yield were detected between cattle types.

Funding Source: Funding for this project provided by the Iowa Beef Industry Council’s State Checkoff Program.

Keywords: beef, breed, cutability.

77 Clean-Label Antioxidants Solutions in Enhancing Pet Food Quality Under Accelerated Shelf-Life Conditions

Snigdha Guha*, Joyjit Saha, Saurabh Kumar, and Christin Kohloff, Kerry Ingredients and Flavors, Beloit, WI 53511, USA *snigdha.guha@kerry.com

Introduction/Objectives: Pet foods are usually produced via mechanical deboning or mechanical separation processes of a wide range of meat sources. Manufacturers also include meat byproducts, such as necks, gizzards, and bones, which help to achieve consistency and texture and contribute to the affordability/palatability of pet food products. However, because of this reason, pet foods are usually very prone to lipid and protein oxidation, which can lead to rancidity, off-flavors, and loss of essential nutrients, ultimately impacting both the palatability and nutritional value of the product. Moreover, pet owners are more conscious about ingredient labels and prefer natural, easily recognizable ingredients. Clean-label antioxidants, such as tocopherols, rosemary extract, and ascorbic acid, align with consumer demands for transparency, as these ingredients are seen as safe and more health promoting compared with synthetic preservatives, such as butylated hydroxyanisole (BHA) and butylated hydroxytoluene. The objective of this study is to test the antioxidant efficacy of 2 clean-label solutions in pet food.

Materials and Methods: To address consumer needs while maintaining production costs, 2 novel clean-label plant-based antioxidant concepts have been developed, namely, FoodGard concept 1 and FoodGard concept 2. This study aimed to determine the efficacy of these 2 antioxidant concepts in reducing lipid and protein oxidation in semimoist pet treats in an accelerated shelf-life condition. Treatments included negative control (no antioxidant), positive commercial control (150 ppm BHA), rosemary at 30 ppm bioactive (clean-label commercial control), and varying concentrations of FoodGard Concepts 1 and 2 (0.3%, 0.5%, and 1%). Treatments were stored under accelerated storage conditions at 45°C and 84% relative humidity for a period of 3 mo, and they were regularly analyzed for their peroxide content (primary lipid oxidation), malonaldehyde (MDA) content (secondary lipid oxidation) via thiobarbituric acid reactive substances, carbonyl content (protein oxidation), and histamine content (biogenic amine content). All differences were compared using 1-way analysis of variance (P < 0.05).

Results: The results of this study demonstrated that the negative control treatment reached peroxide values of at least 20 meq/kg and MDA of at least 5 μg/g (indicating poor fat quality) within 14 and 8 d, respectively. However, both the FoodGard concepts 1 and 2, at 0.05% and 1% doses, were able to limit the primary and secondary oxidation significantly (P < 0.05) over 2 mo under accelerated storage conditions, which was comparable to the positive commercial control. Both the antioxidants were also successful in reducing protein oxidation in the pet treats comparable to the BHA control. Therefore, this study demonstrates the parity of the FoodGard concepts with conventional antioxidant solutions in controlling the oxidative degradation of high-fat pet foods and can also help pet food manufacturers keep their production costs low by using mechanical deboning or mechanical separation processes.

Conclusion: Through this research, we can understand the different types of oxidations occurring in pet food and their negative consequences on pet health. Furthermore, 2 novel plant-based antioxidants were identified that can limit primary and secondary lipid oxidation along with protein oxidation in pet food under accelerated oxidative conditions. This study also helps us to assess the importance of incorporating clean label antioxidant solutions in pet foods to provide safer and high-quality products that support pet health meeting both consumer needs and affordability.

Funding Source: Kerry Inc.

Keywords: pet food, antioxidant, clean-label, accelerated testing.

78 Assessing Pork Spoilage Using Meat Exudate Microbial and Metabolomic Signatures

Saud Ur Rehman¹*, Bruce R. Cooper², Priyanka Ramesh², and Yuan H. Brad Kim¹, ¹Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, USA, ²Bindley Bioscience Center, Purdue University, West Lafayette, IN 47907, USA *rehmans@purdue.edu

Introduction/Objectives: Meat spoilage is a major contributor to food waste in the meat industry. Traditional spoilage detection methods have limitations, highlighting the need for a rapid detection and possibly predictive system. Meat exudate, an easily obtainable aqueous matrix released during storage, contains metabolites associated with microbial activity, making it a promising candidate for assessing meat spoilage and quality. This study aimed to evaluate the efficacy of meat exudate as an analytical medium for assessing spoilage in pork loins during aging. Additionally, metabolomic profiling of both exudate and meat tissue samples was conducted to compare their biochemical signatures and gain deeper insights into the mechanisms underlying meat spoilage.

Materials and Methods: At 7 d postmortem, loin (longissimus lumborum) muscles from market-weight pigs (n = 9) were obtained, cut into 6 parts, vacuum packaged, and stored at 1°C (control) and 10°C (spoilage) for 1, 7, and 14 d. Exudate and meat tissue samples were aseptically collected and enumerated for bacterial (Lactobacillus, Pseudomonas, Enterobacteriaceae, and total bacterial count) counts. Volatile organic compounds (VOC) in exudate were assessed using head-space solid-phase microextraction. The freshness and lipid oxidation of pork loins were determined by measuring total volatile basic nitrogen (TVBN) and 2-thiobarbituric acid reactive substances (TBARS), respectively. Untargeted metabolomic profiles of both exudate and tissue samples were analyzed via ultra-performance liquid chromatography–mass spectrometry. Statistical analysis was performed by using PROC GLIMMIX procedure with SAS 9.4, and metabolomics data analysis was completed through MetaboAnalyst 6.0. Individual main effects were reported if interaction was not found significant (threshold of P < 0.05).

Results: As expected, pork loins stored under spoilage conditions (10°C) exhibited significant microbial growth over time. Microbial counts in pork exudates closely mirrored those in meat tissue throughout storage. After 1 d, microbial levels remained below 3 log CFU in both meat tissue and exudate, indicating minimal to no spoilage regardless of storage condition. At 7 d and 14 d, however, exudate microbial counts increased to 5 to 6 log CFU and 7 log CFU, respectively, under spoilage conditions, signifying partial and complete spoilage. This trend was also observed in meat tissue, reinforcing potential of exudate an analytical matrix for spoilage detection. Additionally, a total of 28 distinct VOC were identified in exudate samples. Among these, acetoin was detected exclusively at 7 d and 14 d under spoilage conditions, whereas compounds such as 4-propylbenzaldehyde and phenol increased over time regardless of the storage conditions. In contrast, methyl isobutyl ketone levels reduced, whereas octanal concentrations increased with spoilage condition (P < 0.05). TVBN levels, a key spoilage indicator, were significantly higher in tissue samples from spoiled meat compared with controls at 14 d. A strong positive correlation (r > 0.6) was observed between TVBN and microbial growth in pork loins. Under spoilage conditions, TBARS levels increased (P < 0.05) regardless of storage duration. Untargeted metabolomic profiling of exudate and tissue identified 3,391 and 3,230 metabolites, respectively. Principal component analysis revealed storage condition-dependent clustering in both matrices. However, tissue samples exhibited substantial overlap, whereas exudate samples demonstrated more distinct separation. Notably, the greatest divergence occurred at 14 d under spoilage conditions, indicating significant biochemical alterations associated with extended storage at elevated temperature. Among the detected metabolites, nucleotide derivatives, such as uridine, xanthine, hypoxanthine, and inosine, along with fatty acid metabolism-related compounds, including carnitine and acyl-carnitines, were more pronounced, suggesting as potential spoilage indicators in both meat tissue and exudates.

Conclusion: The results of the present study explored the potential of meat exudate as an analytical matrix for spoilage assessment, showing microbial growth patterns that were generally comparable to those observed in homogenized tissue samples. VOC profiling further provided supporting evidence for the suitability of exudate for spoilage assessment. Its physicochemical uniformity and ease of collection highlight its practicality for routine quality assessment. Furthermore, untargeted metabolomic analysis revealed preliminary signs of greater discriminatory power in exudate profiles, supporting its potential utility in detecting spoilage-associated metabolic alterations. These findings lay the foundation for further exploration of exudate as a ready-to-use medium for spoilage detection, pending biomarker identification through metabolomics. Ongoing efforts include further annotation and supervised multivariate analyses (e.g., pathway analysis and random forest) to refine biochemical signatures and gain deeper insights into meat spoilage mechanisms.

Funding Source: Purdue AgSEED Grant.

Keywords: spoilage, metabolomics, exudate, volatile organic compounds.

79 Effect of Tumbling at Different Thawing Levels and Post-Tumbling Storage on Quality Attributes of Beef Loins

Sung-Su Kim*, Jin-Kyu Seo, and Yuan H. Brad Kim, Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, USA *kim4737@purdue.edu

Introduction/Objectives: Tumbling is a widely used postharvest processing technique to enhance the palatability attributes of fresh meat. Recent studies suggest that tumbling only (without brine) can lead to an immediate tenderness improvement by physical disruption of muscle fibers. This study hypothesized that tumbling beef at early postmortem may enhance tenderness by accelerating proteolysis during subsequent storage. Additionally, it was proposed that tumbling partially thawed beef could improve tenderness through a combination of physical disruption, cryodamage, and proteolysis. Therefore, this study aimed to evaluate the effects of tumbling and posttumbling storage on the quality attributes of beef at different thawing levels.

Materials and Methods: Striploins (M. longissimus lumborum; left side) from beef carcasses (n = 27; US Department of Agriculture low Choice grade) at 3 d postmortem were obtained. In the first experiment, the loins (n = 13) were cut into 3 sections and randomly assigned to one of the following treatments: nontumbled + no further storage (NTNS), tumbled + no further storage (TNS), or tumbled + 24 h storage (TS). In the second experiment, the remaining loins (n = 14) were cut into 3 sections and randomly allocated to one of the following treatments: fully thawed then tumbled (FT; thawed for 30 h at 4°C), half-thawed then tumbled (HT; thawed for 14 h at 4°C), or tumbled without thawing (UT). All tumbling was applied for 90 min at 8.5 rpm. Thawing loss, tumbling loss, further storage loss, and total loss were measured throughout the process. Upon tumbling, each loin section was cut into 2 steaks for cooking loss, Warner-Bratzler shear force (WBSF), drip loss, myofibrillar fragmentation index (MFI), pH, and bloomed color (CIE a* and chroma) measurements. All traits were analyzed using least-squares means in the PROC GLIMMIX procedure of SAS 9.4. The model included treatment as a fixed effect and animal as a random effect, with post hoc comparisons conducted using the Tukey test at 95% significance level.

Results: TNS and TS exhibited significantly lower total loss and WBSF values, along with higher redness (CIE a*), and color intensity (chroma) compared with nontumbled control (NTNS). Both FT and HT showed higher values for total loss, a*, and chroma compared with UT (P < 0.05); however, no differences were observed between FT and HT for these parameters (P > 0.05). Notably, total loss was lower in both HT and FT compared with UT (P < 0.05), but the difference between FT and UT was not significant (P > 0.05). Additionally, FT and HT demonstrated significantly lower WBSF values than UT, with no significant difference between FT and HT. FT also had higher MFI values than both UT and HT (P < 0.05). No significant differences were observed in cooking loss, drip loss, and pH among all treatment groups.

Conclusion: The results of this study confirmed that tumbling beef without brine addition can improve tenderness, though post-tumbling storage for 24 h had minimal impacts. Tumbling half-thawed beef produced tenderness comparable to fully thawed beef, suggesting its potential as a value-adding process during thawing. Future research should be warranted to determine the impacts of tumbling on other muscles with background toughness, investigate the underlying mechanisms, and determine optimal applying conditions.

Funding Source: US Department of Agriculture (USDA)–Agriculture and Food Research Initiative (AFRI) National Institute of Food and Agriculture (NIFA) (2023-67023) grant.

Keywords: beef quality; beef loin; tenderness; half-thawed; tumbling.

80 Does Freezing Prior to Aging Improve Tenderness of Beef Striploins?

Clayton C. Stevenson*, Megan E. Eckhardt, Loni W. Lucherk, Trent E. Schwartz, and Ty E. Lawrence, West Texas A&M University, Canyon, TX 79016, USA *ccstevenson1@buffs.wtamu.edu

Introduction/Objectives: Calpastatin, the endogenous inhibitor of calpain proteases, is known to be susceptible to inactivation during freezing. A reduction in calpastatin activity may enhance post-thaw proteolysis by calpains as the inhibitory barrier to tenderization is reduced. Furthermore, freezing-induced damage is not limited to the biochemical alterations of regulatory proteins; the physical effects of ice crystal formation also play a pivotal role. During the freezing process, the formation of intracellular ice crystals can rupture cellular membranes, leading to the release of both proteolytic enzymes and their substrates. This mechanical disruption increases the accessibility of myofibrillar proteins to calpains, thereby accelerating the tenderization process upon thawing. Thus, our objective was to determine whether immediate freezing prior to aging could improve beef striploin tenderness.

Materials and Methods: Beef striploin steaks (10 per subprimal) were cut from the anterior end of 10 striploin subprimals (US Department of Agriculture Institutional Meat Purchase Specifications #180) 48 h postmortem. Treatments were arranged in a 2 × 5 factorial arrangement (factors: initial age and postfreeze age). Steaks were randomly allocated to 1 of 2 initial aging treatments (2 d or 9 d postmortem) prior to freezing. Steaks remained frozen for 7 d before allowing 24 h to thaw. At the completion of thawing, steaks were randomly assigned to a postfreeze aging treatment (0 d, 7 d, 14 d, 21 d, 28 d), allowing 10 replications per treatment combination. Purge loss was determined by comparing steak weights at initial cutting and after aging. Steaks were cooked in a forced-air convection oven set at 177°C to an internal temperature of 71°C at the end of their postfreeze aging period. Peak internal temperature was monitored using a thermocouple. Peak internal temperature for each steak was recorded. Tenderness was evaluated using the slice shear force (SSF) method. Following the endpoint temperature reading, a 1- to 2-cm slice was removed across the width of the steak from the lateral end to square off the steak and expose the muscle fibers. Using a cutting guide, a 5-cm-long × 1-cm-thick section was obtained from the lateral end by cutting at a 45° angle parallel to the muscle fiber orientation. The sample was center-sheared perpendicular to the muscle fiber using an Instron universal testing machine with a crosshead speed of 500 mm/min and a 2kN load cell attached to the SSF blade. Peak shear force values were recorded in kilograms. Following a 24-h cooling period, steaks were subjected to Warner-Bratzler shear force (WBSF). Six cores (1.27-cm diameter) were mechanically removed parallel with the muscle fiber, and shear force was evaluated by shearing each core perpendicular to the muscle fibers. Peak WBSF value was recorded for each core and averaged to represent the value of each steak. Data were analyzed using mixed models; initial and postfreeze age were fixed effects, the striploin and steak number were random effects, and, for tenderness, peak temperature was also a random effect.

Results: Both purge loss and cook loss were unaffected by the interaction (P ≥ 0.232) of initial age and postfreeze aging treatment as well as the initial freezing treatment (P ≥ 0.360). Purge loss percentages were impacted by postaging treatments (P = 0.021), but no identifiable trend was determined. Steaks aged for 1 d and 28 d were similar in purge loss percentages but higher than steaks aged 14 d, whereas 7-d and 21-d aged steaks were intermediate. Cook loss percentages (P = 0.043) followed a similar pattern in which steaks aged for 1 d and 28 d were similar in cook loss percentages and greater than 14-d and 21-d aged steaks; 7-d aged steaks were similar to all other aging treatments. No interaction (P = 0.165) existed between pre- and postfreezing aging treatments for SSF. However, both prefreeze aging duration (P = 0.043) and postfreeze aging duration affected (P < 0.001) SSF values. Steaks aged for 9 d prior to freezing had SSF values that were 9.4% lower (P < 0.001) than steaks aged for 2 d prior to freezing. As post-thaw aging duration increased from 0 d to 7 d, 14 d, 21 d, and 28 d, tenderness improved by 25%, 36%, 45%, and 50%, respectively. No interaction (P = 0.721) between pre- and postfreezing aging treatments existed for WBSF. Objective tenderness assessed via WBSF did not differ (P = 0.222) between prefreeze aging treatments. However, as post-thaw aging increased from day 1, WBSF values decreased (P < 0.001) by 35%, 48%, 54%, and 49% for 7-d, 14-d, 21-d, and 28-d aged steaks, respectively.

Conclusion: These results indicate tenderness does not improve with immediate freezing prior to aging on beef striploins. Further research should be conducted assessing this method on tough cuts and cuts from animals with high endogenous calpastatin.

Funding Source: This project was funded by the West Texas A&M University Beef Carcass Research Center.

Keywords: calpastatin, purge, shear force.

81 Processing, Packaging, and Shelf Life: Enhancing the Quality of Large Sturgeon Fillets

Toni Lew Duarte*, Yuyuan Feng, Sudipta Talukder, Bakyzhan Bolkenov, Jackson Gross, and Xiang Yang, University of California Davis, CA 95616, USA *tlduarte@ucdavis.edu

Introduction/Objectives: White sturgeons are highly prized for their roe, which is used to produce caviar. Beyond caviar, their meat is also valued for its flavor and potential health benefits. However, fresh fish is highly perishable, and factors such as processing and packaging methods can significantly affect its quality and shelf life. Optimizing these postharvest methods is essential for preserving freshness and ensuring product stability. Therefore, this study aimed to evaluate how different processing (frozen vs. aged) and packaging (overwrap vs. vacuum) methods influence the quality and shelf life of fillets from large white sturgeons.

Materials and Methods: Sixteen white sturgeons (average weight = 30.37 kg) were stunned using a nonpenetrative captive bolt gun and exsanguinated. After harvest, fish were gutted, filleted, and randomly assigned to 1 of 2 processing methods: either immediately blast frozen (IF; n = 8) or aged at 0°C for 5 d before also being blast frozen (AG; n = 8). Following blast freezing, both groups were stored at −20°C for 30 d. Following their respective frozen storage period, fillets were then thawed at 4°C for 72 h prior to being packaged and placed into the retail display case. Fillets were portioned and packaged in either polystyrene trays with overwrap (OW; n = 16) or vacuum packaging (VAC; n = 16) before being placed in a retail display case at 2°C for 7 d. Objective color (CIE L*, a*, b*) was measured every 24 h using a portable spectrophotometer. Drip loss was determined following storage by weighing the sample, placing it in the retail display case for 48 h, and then removing surface moisture and reweighing. The percentage lost was then calculated. On days 0 and 7, trained panelists (n = 6) were asked to evaluate fillet color, odor, and texture using a 3-point scale (1, desirable; 2, acceptable; 3, unacceptable). Microbial counts were assessed for aerobic psychrotrophic bacteria, aerobic mesophilic bacterial, Enterobacteriaceae, and lactic acid bacteria (LAB). Texture profile analysis (TPA) was conducted on three 1.5 × 1.5 × 3–cm pieces per fillet. Sensory scores were analyzed using a cumulative link model, whereas objective color measurements were analyzed with a linear mixed-effects model with individual fish as a random variable. Microbial, TPA, and drip loss data were analyzed using a 3-way analysis of variance to assess the effects of processing, packaging, and display time, along with their interactions. The α level was defined as 0.05.

Results: Objective color was significantly negatively affected by packaging, with VAC fillets appearing darker (P < 0.05), redder (P < 0.05), and yellower (P < 0.05) than OW fillets. Similarly, AG samples exhibited greater (P < 0.05) redness over time, indicating that they were no longer the desirable bright white in color. Sensory attributes worsened (P < 0.05) over time, with panelists considering all samples unacceptable by day 7, except for the IF OW fillets still being rated as acceptable (mean = 1.89) by 4 out 6 panelists. The initial bacterial populations were similar (P > 0.05) for all the samples. Microbial counts increased (P < 0.05) over time, exceeding the spoilage threshold (7 log CFU/g) by day 7 regardless of processing or packaging type. The IF fillets had higher (P < 0.05) counts than AG fillets for all microbes except LAB by day 7. Texture degraded (P < 0.05) over time for all the fillets, although IF fillets retained higher (P < 0.05) cohesiveness, springiness, gumminess, and chewiness, indicating that immediate blast freezing may aid in retaining structural properties of fillets. Additionally, OW packaging increased the adhesiveness and cohesiveness of fillets compared with VAC (P < 0.05), suggesting that although OW packaging may help in retaining the structure of the fillet, it may also cause the fillet to become sticky and unattractive to consumers. Furthermore, drip loss was significantly impacted by processing type, with AG samples losing twice as much (P < 0.05) during the display time in comparison to IF samples—14.57% and 7.26%, respectively.

Conclusion: Results of this study demonstrate that both processing and packaging methods impact sturgeon fillets’ quality and shelf life. For example, the VAC packaging led to negative changes in color and texture of the sturgeon fillets. Furthermore, immediate freezing appeared to help preserve the structural integrity of the fillets and supported the retention of moisture and desirable textural properties. However, freezing may also contribute to increased microbial counts, potentially shortening shelf life. Therefore, further research is needed to investigate how these processing and packaging methods could be refined to better extend shelf life while maintaining the overall quality of sturgeon fillets.

Funding Source: Western Regional Aquaculture Center.

Keywords: fish, aquaculture, processing, packaging, sturgeon.

82 Clean-label Preservation of Semimoist Pet Foods Under Accelerated Storage Conditions

Jasmine Kataria, Rahul Sharma, Jyoti Aryal*, Saurabh Kumar, Joyjit Saha, and Christin Kohloff, Kerry Ingredients & Flavours, Beloit, WI 53511, USA *jyoti.j.aryal@kerry.com

Introduction/Objectives: Mold contamination in semimoist pet treats poses a significant challenge to the pet food industry, impacting product quality, safety, and consumer perception. With the growing demand for clean-label solutions, this study evaluated the antifungal efficacy and palatability of a cultured whey natural flavor–based antimicrobial, EverWild D01, as a natural preservative for semimoist pet treats.

Materials and Methods: Semimoist pet treats were formulated to a target moisture of 23.0%, water activity of 0.72, and pH of 6.10. Treatments included no preservative (negative control), 0.15% potassium sorbate, 0.30% lactic acid, and EverWild D01 at 0.50%, 1.00%, and 1.50%. Treats were surface-inoculated with Eurotium herbariorum, Penicillium roqueforti, and Aspergillus oryzae, and then stored under accelerated conditions (21°C, 84% relative humidity) to monitor time to mold growth. Mold outgrowth was recorded via daily visual inspection. Palatability testing was performed using uninoculated samples with 20 kennel dogs per day over 2 d (N = 40 dogs). On each day, dogs were offered 2 treats side by side—a test treatment and a control (potassium sorbate or lactic acid). The position of samples was randomized to avoid side bias, and dogs were tested individually. Each dog was given up to 2 min to assess and consume the samples, with a 10-min interval between tests to minimize palate fatigue. First choice and consumption were recorded. This paired preference design follows standard methods used in pet food sensory evaluation. First-choice data were analyzed using a binomial test to determine whether preferences for the treatments differed significantly from random chance (P ≤ 0.05).

Results: Days to first sign of visible mold growth in the negative control and lactic acid treatments occurred between days 25 and 29. The 1.50% EverWild D01 treatment delayed the first sign of visible mold growth to 165, 155, and 171 d for E. herbariorum, A. oryzae, and P. roqueforti, respectively, significantly outperforming 0.15% potassium sorbate (126, 91, and 115 d; P ≤ 0.05, 1-way analysis of variance, JMP Pro v15.1.0). Palatability testing showed that EverWild D01 offered 100% acceptability, comparable to potassium sorbate. Binomial test results confirmed no significant difference (P > 0.05) in first-choice preference, demonstrating parity in palatability.

Conclusion: EverWild D01 effectively delayed mold outgrowth in semimoist pet treats under accelerated storage, providing superior clean-label antifungal performance compared with traditional preservatives. Its parity in palatability to potassium sorbate supports its use as a consumer-friendly solution for mold control in pet foods.

Funding Source: Kerry.

Keywords: clean label, semimoist pet foods.

83 From Catch to Cut: Influence of Harvest and Packaging Methods on Trout Fillet Quality and Shelf Life

Zihan Zhao*, Toni Lew Duarte, Yuyuan Feng, Sudipta Talukder, Bakyzhan Bolkenov, Jackson Gross, and Xiang Yang, University of California, Davis, CA 95616, USA *zluzhao@ucdavis.edu

Introduction/Objectives: In the past year, the total value of trout sales received by growers experienced a steady increase, reaching 108 million dollars in 2024, increasing 8% from the total production in 2023. The trend demonstrates a stronger focus on domestic trout production. However, slaughtering methods could cause stress to fish and negatively impact the meat quality and shelf life of already highly perishable final products. Additionally, the change in the oxygen-permeable rate of the packaging film is likely to affect the microbial spoilage of fish products. Thus, the objective of this study was to evaluate the meat quality and shelf life of trout fillets from animals harvested with different methods and packaged in 2 different methods.

Materials and Methods: A total of 18 trout were harvested utilizing 1 of 3 methods: a traditional method of submersion in ice slurry (ICE; n = 6), an alternative method of either electricity (EL; n = 6), or nonpenetrating captive bolt (CAP; n = 6). Following slaughter, the fish were gutted, cleaned, and filleted at a commercial facility. Fillets were then placed on ice and transported back to the University of California, Davis meat lab where they were packaged in either polystyrene trays with overwrap (OW) or in vacuum (VAC) packaging before being placed into a retail display case for 10 d at 2°C. Objective color was measured every 24 h using a portable spectrophotometer. On days 0, 5, and 10, panelists (n = 6) were asked to evaluate the color, odor, and texture of fillets using a 3-point scale (1, desirable; 2, acceptable; 3, unacceptable). Samples were then taken from the fish to determine microbial counts for aerobic psychrotrophic bacteria (APC), Enterobacteriaceae, lactic acid bacteria (LAB) and Pseudomonas spp. (PS). Drip loss was measured by weighing a sample before packaging, storing it in a display case for 48 h, removing surface moisture, and reweighing. The percentage loss was then calculated. Sensory data were analyzed using a cumulative link model. Objective color data were analyzed using a linear mixed-effects model with fish treated as a random variable. Microbial data were analyzed using a 3-way analysis of variance to investigate treatment, display time effect, and their corresponding interactive effects. The α level was defined as 0.05.

Results: The objective color of the VAC samples was lighter, redder, and yellower (P < 0.05) compared with the overwrapped samples. Although VAC samples received higher evaluation scores (P < 0.05) compared with OW samples, all samples were rated as unacceptable for color, odor, and texture on day 10 regardless of packaging types or harvest method. All microbial counts increased (P < 0.05) over time. Samples in VAC had lower (P < 0.05) microbial counts (APC, LAB, PS) compared with samples in OW on day 5. The EL samples had the lowest (P < 0.05) APC counts compared with the ICE and CAP groups. However, counts for all bacteria types exceeded the level indicative of spoilage (7 log CFU/g) on day 10 for all the samples regardless of harvest or packaging methods. The drip loss was similar (P > 0.05) throughout the slaughtering and packaging methods, with only OW samples showing an increase (P < 0.05) in moisture loss from day 0 (<1%) to day 10 (>9%).

Conclusion: The results of this study indicated that both slaughtering and packaging methods significantly impact the quality and shelf life of trout fillets. Fillets packaged in VAC packaging seem to have increased sensory quality, reduced microbial counts, and reduced moisture loss compared with those packaged in OW. Additionally, fillets from fish processed using the EL method generally had lower total microbial counts compared with the ICE and CAP groups. These findings indicate that fish slaughtered using electricity followed by vacuum packaging would improve quality and shelf life of trout fillets.

Funding Source: Western Regional Aquaculture Center.

Keywords: fish, shelf life, meat quality, slaughter, packaging.

84 Influence of Carcass Chilling Systems on Primal Temperature Decline and Lean and External Fat Color of Bison Bull and Heifer Carcasses

Lydia M. O’Sullivan¹*, Garrett. T. Weldy², Jameson R. Brennan², Christina E. Bakker², J. Kyle Grubbs², Keith R. Underwood², and Amanda D. Blair², ¹Department of Animal and Equine Science, Murray State University, Murray, KY 42071, USA, ²Department of Animal Science, South Dakota State University, Brookings, SD 57007, USA *losullivan@murraystate.edu

Introduction/Objectives: Postmortem chilling is a critical step in carcass processing necessary to ensure food safety, reduce shrinkage, and allow for development of meat quality attributes, such as color. Chilling has been heavily investigated in the beef and swine industries because of its significant impact on meat quality and safety. Research in these species has demonstrated that factors such as chilling system and carcass size can impact the rate of chilling and subsequent meat quality outcomes, such as color. In the bison industry, both conventional air chilling and vascular chilling systems are commonly used to chill bison carcasses. However, information on the effect of different chilling systems on temperature decline in bison primals and subsequent effects on meat color is lacking. Therefore, the objective of this study was to evaluate the influence of chilling systems on primal temperature decline and lean and external fat color of bison bull and heifer carcasses.

Materials and Methods: Temperature decline of bison carcasses (n = 280) was evaluated at 2 processing plants that employ different chilling methods. Chilling treatments consisted of conventional air chilling (n = 140) and a vascular rinse system (n = 140), wherein a chilled isotonic solution (MPSC, Inc., St. Paul, MN) was rinsed through the carotid artery and jugular vein following exsanguination. The isotonic solution consisted of water, glucose, maltose, and phosphates. An equal number of bison bulls and heifers were evaluated at each facility (n = 70 of each sex per facility). Prior to carcass chilling, temperature data loggers were inserted into one side of each carcass to monitor temperature decline at 3 primal locations. One data logger (20.32 cm) was placed in the center of the round primal near the femur. One data logger (10.16 cm) was placed in the loin primal at the third lumbar vertebra, and one data logger (20.32 cm) was placed in the center of the chuck primal. Internal temperature was recorded every 5 min for a maximum of 18 h, and loggers were removed prior to fabrication. Following carcass chilling, color (L*, a*, b*) of the lean surface of the ribeye and external fat opposite the ribeye were recorded. To assess the rate of temperature decline, self-starting asymptotic regression models were fit for each individual carcass using the function (SSasymp) in the “stats” package of Program R (R Core Team, 2022). Bison bull and heifer temperature decline data were analyzed separately. Data were analyzed using the MIXED procedure of SAS (SAS Inst. Inc., Cary, NC) with rate of temperature decline as the response variable and fixed effects of primal, chilling system, and their interaction. Hot carcass weight was included as a covariate but omitted from the model if not significant. Lean and external fat color were analyzed separately using the MIXED procedure of SAS for the fixed effect of chilling system. Backfat measurement was included as a covariate but omitted from the model if not significant. Collection was included as a random effect, and carcass served as the experimental unit for all data. Statistical significance was considered at P value of 0.05 or less.

Results: A treatment by primal interaction (P = 0.0012) was observed for temperature decline in bison bulls. Chilling treatment did not influence (P ≥ 0.28) chilling rate in the chuck or the round of bull carcasses; however, loins from conventionally chilled bull carcasses had a faster (P = 0.02) chilling rate compared with loins from vascularly chilled bull carcasses. There was no difference (P = 0.45) in L* values of the lean surface between chilling treatment of bull carcasses. Vascular chilled bull carcasses had lower (P < 0.0001) a* and b* values of the lean surface compared with conventionally chilled carcasses. Vascularly chilled bull carcasses had greater (P = 0.0002) L* values of the backfat opposite the ribeye than conventionally chilled bull carcasses, whereas conventional chilling resulted in greater (P < 0.0001) a* and b* values. A treatment by primal interaction (P < 0.0001) was observed for temperature decline in bison heifers. The round and chuck primals of vascularly chilled heifer carcasses had faster (P ≤ 0.002) chilling rates compared with conventionally chilled. However, no differences (P = 0.14) were observed between the 2 treatments for chilling rate in the loin of heifer carcasses. Conventionally chilled heifer carcasses had greater (P ≤ 0.0003) L*, a*, and b* values of the lean surface of the ribeye compared with vascularly chilled heifers. Chilling treatment did not influence (P = 0.21) L* of the backfat opposite the ribeye. However, conventional chilling resulted in greater (P < 0.0001) a* values of backfat, whereas vascular chilled heifer carcasses had greater (P < 0.0001) b* values of backfat.

Conclusion: These data indicate that the temperature decline of bison primals is differentially influenced by carcass chilling systems. The differential response by primals could be reflective of differences in primal size, fat cover of each primal, and effectiveness of the specific chilling treatment at a particular location on the carcass. These factors could impact heat generation during postmortem metabolism as well as heat removal during chilling and warrant further investigation. Lean and fat color was also influenced by chilling method. Taken collectively, these results provide a benchmark for bison carcass chilling that can help guide future research and marketing efforts to ensure product consistency. Improved understanding of the factors that impact chilling rate could lead to strategies to optimize chilling processes for bison and support efforts to meet consumer demands.

Funding Source: This research was funded by state and federal funds appropriated to South Dakota State University, including support from the South Dakota State University Agriculture Experiment Station, National Institute of Food and Agriculture through the Hatch Act (accession no. 7008365), South Dakota State Center of Excellence for Bison Studies, and Turner Institute of EcoAgriculture.

Keywords: bison chilling, temperature decline, color.

85 Investigating Processing Facility Influence on Ground Beef Shelf Life

Cameron Catrett¹*, Peyton Arnold¹, Ashley Pitti¹, Palika Dias-Morse¹, Morgan Denzer², Jacob Tuell³, Edward Yancey⁴, and Derico Setyabrata¹, ¹Department of Animal Science, University of Arkansas, Fayetteville, AR 72701, USA, ²Department of Food Science, University of Arkansas, Fayetteville, AR 72701, USA, ³School of Agricultural Sciences, Northwest Missouri State University, Maryville, MO 64468, USA, ⁴Tyson Foods Inc., Springdale, AR 72762, USA *ccatrett@uark.edu

Introduction/Objectives: Ground beef is a popular meat product that accounts for nearly 40% of retail beef purchases, but because of processing and grinding, it often has reduced color quality and shelf life. Researchers have begun to investigate how processing facility conditions may impact product shelf life. Recent studies found that microbiome populations differ between processing facilities and could impact product color quality. The objectives of the current study were to characterize processing facility influence on ground beef shelf ife.

Materials and Methods: Ground beef chubs (N = 9/facility; 80% lean, 20% fat) were collected from 2 commercial processing plants (P1 and P2) and equally but randomly assigned to processing at 1 of 2 secondary processing facilities (UA and NW). Chubs were fine ground (3-mm plate) to form 450-g loaves (n = 2 per chub), placed on foam trays with an absorbent pad, overwrapped with polyvinyl chloride film, and placed in simulated retail display for 5 d with color measurements taken every 24 h. On day 1 and day 5, samples were analyzed for pH, microbial enumeration (aerobic bacteria and lactic acid bacteria), and thiobarbituric acid reactive substances (TBARS). The study was a randomized complete block design with split-split-plot arrangement and the fixed effects of source plant, processing facility, display day, and their interactions. The collection period served as the block, the source plant as the whole plot factor, the processing facility as the split-plot factor, and the display day as the split-split-plot factor. Data were fit using a mixed model and analyzed using the lme4 and emmeans packages in RStudio. Differences were considered significant at P value less than or equal to 0.05.

Results: There was a plant × day interaction (P < 0.01) for both a* values and chroma in which P2 had decreased values for each attribute throughout display, indicating decreased color stability compared with P1. Moreover, there was secondary facility × day interaction (P < 0.01) for a* values and chroma in which NW loaves were less red and had decreased color saturation during display than UA (P < 0.01). There was a plant × day interaction (P = 0.02) for TBARS in which P2 day 5 values had greater oxidation detected compared with P1 day 1 and day 5 (P < 0.01), but P1 day 1 and P2 day 1 TBARS values did not differ from each other (P = 0.84). There was a plant × day interaction (P < 0.01) for pH in which P2 day 5 samples had decreased pH compared with P1 day 1 and day 5 samples as well as P2 day 1 samples (P < 0.01). There were no 2-way or 3-way interactions observed for both aerobic plate counts and lactic acid bacteria counts (P > 0.07); however, there were both plant and day main effects observed in which P2 had elevated plate counts compared with P1, and day 5 plate counts were greater than those of day 1 (P < 0.01).

Conclusion: The current results suggest the processing plant has a greater influence on ground beef color, microbial growth, and oxidative quality, whereas the secondary processing facility only impacted product color during display. Further analyses are being conducted to characterize the product microbiome from each facility and determine its relationship with shelf-life attributes.

Funding Source: Research was coordinated by the National Cattlemen’s Beef Association, a contractor to the Beef Checkoff.

Keywords: bacteria, beef, discoloration, facility, oxidation.

86 Effect of Vibration Isolation During Transportation on Beef Sirloin Subprimal and Steak Quality

Kyle Krueger*, Christina Bakker, Keith Underwood, Amanda Blair, Kyle Grubbs, Department of Animal Science, South Dakota State University, Brookings, SD 57007, USA *kylie.krueger@sdstate.edu

Introduction/Objectives: Although the influence of live animal transportation on product quality outcomes has been extensively studied, minimal research has been conducted on the effects of transportation on beef subprimal and case-ready product quality. In the meat industry, products can be transported several times between the source plant and the consumer. Previous research has reported that temperature during transportation directly impacts water holding capacity of beef sirloin subprimals. Additionally, produce transportation research has suggested roadway vibrations play a major role in damaging products during transport. However, data investigating the impact of transportation conditions on beef quality are lacking. Therefore, the objective of this study was to determine the influence of vibration during transportation on water holding capacity, color, and tenderness of beef sirloin subprimals and steaks.

Materials and Methods: US Department of Agriculture Choice center-cut sirloin top butts (n = 45 cases) were collected from a commercial processing facility and randomly allocated to 1 of 3 treatments (n = 15 cases/treatment) for transport (day 0). Treatments were (1) regular pallet transported 241 km (Reg241), (2) regular pallet transported 644 km (Reg644), and (3) vibration isolation pallet (wire coil isolators designed to support 500–600 kg) transported 644 km (Iso644). All subprimals were transported at −2.2°C. Following transport, subprimals were stored for 10 d (at 1.4°C ± 2.5°C) to mimic industry practices for product storage and aging. Following storage (day 11), 1 subprimal per box was evaluated for purge loss and fabricated into 3- to 2.54-cm-thick steaks from the anterior end. Ultimate pH was measured on the posterior end of the subprimal. Steaks were further bisected into medial and lateral sections (n = 6 steaks). Medial steaks were evaluated fresh, whereas lateral steaks were evaluated after freezing and thawing. All steaks were weighed, and initial objective color was recorded on the lateral day 12 steak at fabrication. Data were collected for purge loss, cook loss and Warner-Bratzler shear force (WBSF) on all steaks at 3 different project time points: (1) subprimal transport (day 12), (2) steak transport (day 23), and (3) steak transport plus a 6-d retail display (day 28). All medial day 12 steaks were evaluated on day 12 to represent subprimal transport, and lateral day 12 steaks were frozen. All other steaks were overwrapped and packaged in modified atmosphere mother bags for a second transport on regular pallets for an additional 483 km. All steaks were held for 5 d following second transport, prior to day 23 steak evaluation of purge loss, cook loss, and WBSF. A 6-d objective color retail display was conducted on day 28 steaks before evaluating purge loss, cook loss, and WBSF. Data were analyzed using the MIXED procedure of SAS, with fixed effects of treatment, day, and their interaction. Peak cooking temperature was included as a covariate for WBSF and cook loss. Separation of least-squares means was performed using a Tukey’s adjustment (assuming an α ≤ 0.05).

Results: A treatment effect was observed for subprimal L* (P = 0.0253). Steaks fabricated from Reg644 subprimals were darker (41.44 ± 0.60) than Iso644 (43.64 ± 0.60; P = 0.0338). Reg644 steaks also tended to be darker than Reg241 steaks (43.37 ± 0.60; P = 0.0692). A treatment × day interaction was observed for fresh steak purge loss (P < 0.0001). Purge loss increased 2.33% between day 12 and day 23 for Reg241 (P < 0.0001) and 1.41% for Iso644 (P = 0.0007) steaks. Purge loss decreased across all treatments during the retail display (day 23 vs. day 28; P < 0.05 for all). The Reg241 treatment exhibited 1.33% higher purge loss on day 23 than Reg644 (P = 0.0297), whereas Iso644 was intermediate and similar to both treatments (P > 0.05). Throughout the retail display, a tendency for a treatment effect was observed for L* (P = 0.0679). Reg644 steaks tended to be darker (40.28 ± 0.72) compared with Reg241 (42.38 ± 0.72; P = 0.0807); meanwhile, Iso644 was intermediate and not different from either treatment (P > 0.05). A day effect was observed for a* and b* as values decreased from day 23 to day 28 (P < 0.0001). Both treatment (P = 0.0020) and day (P = 0.0033) effects were observed for fresh steak cook loss. Reg241 steaks exhibited 3.12% greater cook loss compared with Reg644 steaks (P = 0.0013), whereas Iso644 was intermediate and similar to both treatments (P > 0.05). Cook loss also decreased 2.85% between day 12 and day 23 (P = 0.0022), whereas day 28 was intermediate and not different from either time point (P > 0.05). No treatment effect was observed for WBSF (P > 0.05) in fresh steaks, although a day effect was observed (P = 0.0219). Tenderness improved from day 23 to day 28 (P = 0.0219). A treatment × day interaction was also observed in purge loss of frozen steaks (P = 0.0027). Purge loss increased 1.9% between day 12 and day 23 for frozen Reg241 steaks (P < 0.0001) and 1.6% for Iso644 (P < 0.0001) but remained similar at day 28 (P > 0.05). Purge loss was not different for Reg644 steaks across all 3 time periods (P > 0.05). A day effect was observed for cook loss of frozen steaks (P = 0.0020). Cook loss decreased 2.31% from day 12 to day 23 (P = 0.0050) and 2.23% on day 28 (P = 0.0071).

Conclusion: Results indicate increased distance of transport and vibration exposure positively impacts meat quality attributes. Improvements in both water holding capacity through reductions in both purge and cook loss as well as beef color were observed in sirloin steaks and subprimals that experienced vibrations for longer distances. Ultimately, vibration isolation implementation during transport had minimal effect on sirloin cuts. Additional research is warranted to further confirm the impact of transport on meat quality.

Funding Source: Funded in part by The Beef Checkoff through the South Dakota Beef Industry Council and by state and federal funds appropriated to South Dakota State University, including support by the US Department of Agriculture National Institute of Food and Agriculture, Hatch Project (accession no. SD00H775)

Keywords: beef quality, vibration isolation, transportation.

87 Impact of Salt Block Utilization During Dry Aging on Pork Loin Microbial and Meat Quality

Cason Frisby¹*, Morgan Denzer¹, Cameron Catrett², Peyton Arnold², Stephanie Shimer², and Derico Setyabrata², ¹Department of Food Science, University of Arkansas, Fayetteville, AR 72701, USA, ²Department of Animal Science, University of Arkansas, Fayetteville, AR 72701, USA *cfrisby@uark.edu

Introduction/Objectives: Pork is the most widely consumed meat in the world. Consumers desire high-quality pork and pork products. However, historical consumer trends favoring low-fat content have negatively impacted pork quality. Postmortem aging is commonly practiced in the meat industry to improve meat quality and palatability following harvest. This is often practiced as wet aging (WA), wherein muscle cuts are held in vacuum bags at refrigerated temperatures. Dry aging is a traditional aging method that has been regaining consumer interest because of its distinctive flavor and eating qualities following the process. Numerous studies have measured these aspects in dry-aged beef, but few studies have done so in pork. Furthermore, even fewer studies have focused on the effects of the widespread practice of using salt blocks in dry-aging chambers. The objective of this study was to investigate the effects of dry aging and salt block utilization on pork loin quality attributes.

Materials and Methods: Six pork loins from one side of the animal (M. longissimus lumborum) were collected at 7 d postmortem, cut into 3 equal sections, and randomly assigned to 3 groups for 28 d aging (WA, traditional dry aging [DA], and salt block dry aging [SDA]). The WA sections were vacuum packed individually and aged in waxed boxes at 2°C. Both DA and SDA sections were aged in dry-aging cabinets set at 2°C and 75% relative humidity. For SDA, salt blocks were placed in the cabinet following the manufacturer’s guidelines. Following aging, both DA and SDA sections were trimmed of their desiccated crusts. Microbiological samples were then taken from lean and crust/surface portions of all samples for aerobic plate counts (APC), lactic acid bacteria counts (LAB), yeast, and mold. All loin sections were cut into chops (2.54 cm) and subjected to meat quality and chemical analyses, including pH, water holding capacity, and Warner-Bratzler shear force (WBSF). Chops were also collected for a 7-d retail color simulation, with daily instrumental color evaluation using a Hunter Miniscan. Lipid oxidation was analyzed before and after the display. This study was a complete block design, in which the carcass served as a block and aging treatment as the fixed effect. Data were analyzed using the PROC GLIMMIX procedure of SAS, and least-squares means for all traits were separated at P value less than 0.05.

Results: At the end of aging treatment, meat pH was similar regardless of treatment (P > 0.05). DA and SDA loins reported greater water holding capacity as indicated by lower drip loss and cook loss compared with WA loins (P < 0.05). There was no difference in shear force values between aging treatments (P < 0.05). Lightness (L*) was not affected by the different aging treatments or display day (P > 0.05). Yellowness (b*) decreased throughout the display period (P < 0.05), regardless of the aging treatment. A significant treatment × day effect was observed for redness (a*), hue angle, and chroma, wherein both DA and SDA had greater hue angle and reduced redness and chroma compared with WA from day 5 until the end of display. A significant treatment effect was observed for APC and LAB, exhibiting a greater microbial count in both the lean and crust portions of the WA samples compared with the lean and crust portions of the DA and SDA samples. Lower yeast and mold concentration was observed on DA crust compared with WA and SDA crust (P < 0.05). No significant differences were observed on yeast and mold concentration of the lean portion of all treatments. Thiobarbituric acid reactive substances analysis of samples at day 0 and day 7 of retail color display showed both significant treatment and day main effects, with SDA showing greater lipid oxidation than DA and WA. During the dry-aging period, SDA cabinet exhibited lower humidity fluctuation (average 71.52, SD 4.7) compared with DA cabinet (average 70.76, SD 7.9).

Conclusion: The results of this study suggest that salt block utilization during dry aging only minimally impacts the final meat quality and microbiological attributes. Although the utilization of salt blocks generated a stabler dry-aging environment, minimal differences were observed between DA and SDA products. Further studies to investigate the impact on flavor volatile changes and consumer acceptance or preference following salt block dry-aging pork will be warranted.

Funding Source: This research is funded by the University of Arkansas Honors College.

Keywords: pork, dry aging, salt block dry aging.

88 Marination Properties of Broiler Breast Fillets Dipped in Peracetic Acid

Adalyn M. Hanning¹*, Joaquin J. Esquivel², Sarah E. Johnson², Tomi Obe², and Casey M. Owens², ¹Har-Ber High School, Springdale, AR 72762, USA, ²University of Arkansas, Fayetteville, AR 72701, USA *adalynhanning12@gmail.com

Introduction/Objectives: Peracetic acid (PAA) is commonly used in poultry processing as an antimicrobial during chilling and dip applications. Recently, boneless breast fillets have been dipped multiple times after deboning in order to ensure food safety. The objective of this study was to determine the effects of PAA on breast meat quality through storage and after marination.

Materials and Methods: In this study, broiler breast fillets (n = 225) were obtained after deboning and separated randomly into 5 groups: negative control (NC; no dip), water control (dipped once in water), PAA1 (dipped once in PAA), PAA3 (dipped 3 times in PAA), and PAA5 (dipped 5 times in PAA). Fillets were dipped for 15 s in water or PAA, and for treatments with multiple dips, a 90-s wait period was used in between dips. Each treatment was replicated 3 times (n = 45 per treatment over 3 replications). Fillets were stored for 48 h at 4°C and then vacuum tumble marinated (30 min) with a target pickup of 15% and a final concentration of 0.75% NaCl and 0.45% sodium phosphate. Fillets were cooked 24 h after marination. Fillet attributes including weight, pH, and color (L*, a*, b*) were measured before treatment on day 1 and at day 3 after treatment and storage (n = 45 per treatment over 3 replications) and again after marination. Drip loss, purge, cook loss, and overall cook yield (from initial weight) were calculated. Data in the completely randomized design were analyzed using analysis of variance. Means were separated with Tukey’s honestly significant difference using P < 0.05 to determine significance.

Results: There were no differences (P > 0.05) in initial weight pH or L*, a*, and b* among treatments. There was no difference (P > 0.05) in pickup percentage between water dip control (WC) and PAA1, but PAA3 and PAA5 had higher (P < 0.05) dip pickup percentage than WC and PAA1. PAA5 was higher (P < 0.05) than all treatments. Drip loss (storage of 2 d) followed a similar pattern among treatments (PAA 5 > PAA3, P < 0.05; NC > PAA1 and WC, P < 0.05). After storage, there was no difference (P > 0.05) in pH on day 2 among treatments. Dipping in PAA5 times resulted in higher (P < 0.05) L* than dipping in PAA3, PAA1, or water. Dipping in PAA (1 to 5 times) had higher (P < 0.05) L* than NC, and WC was intermediate. Dipping in PAA3 or PAA5 resulted in lower (P < 0.05) a* than PAA1, WC, or NC. Dipping in PAA1 had lower a* than NC but was similar to WC. There were no differences (P > 0.05) in b* values among treatments. After marination, PAA5 had lower marination pickup and lower purge (after 24 h) than all other treatments (P < 0.05), which were similar (P > 0.05). L* values tended to increase with increasing number of PAA dips even after marination. PAA5 had higher (P < 0.05) L* than all other treatments. PAA3 and PAA1 were similar (P > 0.05), and both were higher (P < 0.05) than NC, but PAA1 was similar (P > 0.05) to WC for L* value. WC and NC did not differ (P > 0.05) in L* value. PAA5 and PAA3 had a lower (P < 0.05) a* value than WC and NC. PAA1 was similar (P > 0.05) to both NC, WC, and PAA3 for a* value. There were no differences (P > 0.05) in cook loss (from marinated weight) among treatments. However, cook yield (pretreatment initial weight through cooking) was lower (P < 0.05) for PAA5 compared with all other treatments, which did not differ. PAA3 was lower (P < 0.05) in cook yield than NC but similar to WC.

Conclusion: Dipping in PAA multiple times can have negative impacts on quality attributes, specifically color (lightness) and quality attributes associated with marination may also be impacted. In this study, dipping broiler breast fillets 5 times in PAA resulted in lighter fillets with lower water holding capacity in terms of drip loss, lower marination pickup, and lower cooked yield of marinated fillets.

Funding Source: Novus International Professorship.

Keywords: peracetic acid, breast, marination, quality.

89 Impact of Aging, Cookery Method and Degree of Doneness on Improving Tenderness of Longissimus Lumborum Steaks From Mature Beef Cull Cows

Tessa A. Maurer* and Cody L. Gifford, Department of Animal Science, University of Wyoming, Laramie, WY 82071 USA *tmaurer1@uwyo.edu

Introduction/Objectives: The objective of this study was to evaluate the impact of objective tenderness of longissimus lumborum steaks from carcasses of mature cull cows due to different postmortem aging period, cookery methods, and degree-of-doneness targets.

Materials and Methods: Mature crossbred-Angus cull cows (n = 14; >42 mo of age that were fed primarily a long-term grass-hay diet) were harvested at the University of Wyoming Meat Laboratory. After carcass chilling, carcass characteristics consisting of ribeye area, fat thickness, marbling score, objective color, yield, and quality grade information were measured and recorded. Vacuum-packaged striploin portions were aged at 0°C to 4°C in dark storage for 14 d or 28 d. After completion of aging, 2.54-cm-thick steaks were fabricated, vacuum packaged, and frozen at −20°C until cooking occurred. Randomized steaks were thawed to 0°C to 4°C prior to cooking and tenderness evaluation. Steaks were cooked via combi oven (oven temperature = 204°C dry heat), 30-min sous vide, or 90-min sous vide cookery treatments to an internal temperature of 60°C or 71°C. Precook temperature, precook weight, cook time, postcook temperature, and postcook weight were recorded. Steaks assigned to the sous vide cookery method were repackaged in high-temperature vacuum bags prior to cooking in either 60°C or 71°C preheated water baths for 30 min or 3 h. Slice shear force (SSF) and Warner-Bratzler shear force (WBSF) were conducted on each cooked steak. Models included the fixed effects of cooking (oven, 30-min sous vide, and 90 minutes sous vide), peak internal temperature (60°C or 71°C), aging duration, and their interaction. Peak cooked temperature of each steak was included as a covariate. Data were analyzed using the lmer function from the lme4 package using R statistical software. Means were separated with Bonferroni adjusted pairwise comparisons using the emmeans package. Significant effects and pairwise comparisons were determined based on α less than or equal to 0.05.

Results: An interaction between cooking method and degree of doneness impacted (P < 0.0001) WBSF, in which steaks cooked via sous vide for 30 min to 60°C internal temperature were more tender than steaks cooked via oven to the same internal temperature. The main effect of aging duration resulted in lower WBSF (P < 0.0001) tenderness among steaks aged for 28 d compared with 14 d of aging. The main effect of degree of doneness resulted in lower SSF tenderness for steaks cooked to 60°C compared with 71°C. There was an interaction of cooking method and degree of doneness (P = 0.0152) that impacted cooking loss in which steaks cooked via sous vide for 30 min to an internal temperature of 60°C had the lowest cooking loss.

Conclusion: Short-term sous vide cooking of longissimus lumborum steaks from carcasses of cull cows for 30 min to an internal temperature of 60°C improved WBSF tenderness and reduced cook loss. Future planned work to assess the impact of these cookery methods on flavor development in addition to evaluating other drivers of tenderness will help to better characterize sous vide as a viable cookery option for muscles from carcasses produced by cull cows.

Funding Source: Internal funding.

Keywords: beef, sous vide, tenderness.

90 Effect of Varying Dip Frequency of Peracetic Acid on Quality of Broiler Tenderloins When Followed by Marination

Joaquin J. Esquivel^1,*, Sarah E. Johnson¹, Adalyn M. Hanning², Tomi Obe¹, and C. M. Owens¹, ¹University of Arkansas, Fayetteville, AR 72701, USA, ²Har-Ber High School, Springdale, AR 72762, USA *je043@uark.edu

Introduction/Objectives: Food safety is of utmost importance in broiler meat production. Antimicrobials such as peracetic acid (PAA) is used frequently in broiler processing and PAA dips are becoming more popular for use after deboning.This research aimed to evaluate the impact of varying dip frequency of peracetic acid on quality of broiler tenderloins when followed by tumble marination after antimicrobial treatment.

Materials and Methods: Tenderloins were randomly separated into 5 treatments: negative control with no dipping (NC), 1 water dip control (WC), 1 dip in PAA (PAA1), 3 dips in PAA (PAA3), and 5 dips in PAA (PAA5), using n = 45 per treatment over 3 replications. Each group was dipped for 15 s in 750 ppm PAA or water, and a 90-s wait period was used between multiple dips. The tenderloins were subjected to tumble marination with a vacuum of 21 mm Hg for 5 min and storage for 24 h. Marinade was formulated to a 0.75% NaCl and 0.45% sodium phosphate for final concentration using a targeted 15% marination addition. Tenderloin pH, color L*, a*, b*, percentage dip pickup (postdip), percentage marination pickup, percentage drip loss (after storage), percentage cook loss, and percentage cook yield (initial pretreatment through cooking) were assessed. Data were subjected to 1-way analysis of variance (P < 0.05). Means were separated using Tukey´s honestly significant difference (using P < 0.05 for significance).

Results: No difference (P > 0.05) was observed among treatments in initial pH, L*, a*, and b*. However, dipping tenderloins multiple times in PAA resulted in lower (P < 0.05) pH after storage compared to 1 dip in PAA, water, or the negative control dipping tenderloins multiple times in PAA. In addition, these treatments resulted in higher (P < 0.05) L* after storage compared with 1 dip in PAA, water, or the negative control. The a* values decreased in PAA3 and PAA5 (P < 0.05). PAA5 had a higher (P < 0.05) pickup after dipping compared with all other treatments. PAA1 and PAA3 had a higher (P < 0.05) marination pickup than PAA5. However, no significant differences (P > 0.05) were found for cook loss or cook yield among the treatments when marinating.

Conclusion: Results indicate that varying PAA dip frequency can decrease the pH, a*, pickup after dipping, and marination pickup. Different quantities of peracetic acid dips can impact color and water holding capacity before and after marination, resulting in a direct impact on meat quality.

Funding Source: Novus International Professor.

Keywords: peracetic acid, tenderloins, meat quality, dipping, marination.

91 A Comparison of Instrumental Camera Technologies on Predicting Intramuscular Fat Percentage

Will W. Boyd¹*, Megan E. Eckhardt¹, Willy J. Horne¹, Bucky L. Gwartney², Ty E. Lawrence¹, Trent E. Schwartz¹, and Loni W. Lucherk¹, ¹Department of Agricultural Sciences, West Texas A&M University, Canyon, TX 79016, USA, ²Agricultural Marketing Service, US Department of Agriculture, Washington, DC, USA *wboyd@startkleen.com

Introduction/Objectives: The consumer is continuing to demand higher-quality beef. According to the 2024 US Department of Agriculture (USDA) National Steer & Heifer Grading Report, cattle fed and harvested in the United States were 9.71% Prime, 72.14% Choice, 14.99% Select, and 3.17% lower grades. Previous research has documented that a higher-quality grade will correspond with a more satisfactory eating experience because of the increased percentage of intramuscular fat (%IMF) within higher grades. As carcass quality continues to increase, as a result of consumer demand, there is potential value in documenting the relationship between instrumental marbling score and %IMF. Therefore, the objective of this study was to document the relationship between instrumental technology marbling and chemically determined %IMF.

Materials and Methods: Beef ribs (USDA Institutional Meat Purchase Specifications no. 103; n = 24) representing 4 quality levels (USDA Prime, Premium Choice [High and Average Choice], USDA Choice, and USDA Select) were sourced from a commercial beef processing facility and transported to the West Texas A&M University meat laboratory. Ribs were assigned to 1 of 3 chilling temperatures (−2.2°C, 3.3°C, 8.9°C) using a completely randomized design, with equal representation of quality levels (grade) among temperature (2 ribs/grade/temperature). Rooms were set to the respective temperatures, and ribs were allowed 48 h to equilibrate. One-cm-thick slices were cut from the posterior end of each rib to simulate the ribbing and blooming process 4 sequential times. Rib surfaces simulated for ribbing (n = 96) were evaluated for objective image analysis marbling via 4 independent devices (E+V VBG 2000 [EV; US camera], E+V VBG Smart [EVH; portable camera], MEQ Camera [Australian camera], and MIJ Camera [Meat Image Japan camera]). Camera image marbling was collected across time after simulated ribbing (0.5, 2, 4, 6, 8, 10, 14, 18, 22, 26, 30, 38, 46, 60, 120, 240, and 480 min). Ribeye cross-section slices simulated for ribbing were frozen at 0°C until chemical fat analysis. Rib slices were processed leaving only the longissimus dorsi muscle. Following dissection, each steak was cut into 1-cm³ pieces and submerged into liquid nitrogen until all pieces were completely frozen. Frozen samples were removed using a stainless-steel skimmer, transferred into a professional blender, and pulverized for approximately 30 s on high speed (5,000 RPM) until a homogenous powder was formed. A 50-g aliquot of the homogenate was obtained for proximate analysis. Samples were labeled, placed in plastic bags, and stored until analysis at SDK Laboratory (Hutchinson, KS), where intramuscular fat was extracted using petroleum ether (AOCS Method Ba 3-38 2009). Data were analyzed using SAS (version 9.3; SAS Institute Inc., Cary, NC). The CORR procedure was used for calculating and determining significance (P < 0.05) of all correlation coefficients. Prediction equations for %IMF were determined using regression analysis (REG procedure). Slope equality was tested using a single degree of contrasts constructed in the general linear model procedure.

Results: Linear prediction equations for %IMF using instrumental marbling score outputs across all temperatures are contained in Table 1. At all temperatures, slopes of all instruments differed from the MIJ system (P ≤ 0.014). All other instruments (EV, EVH, MEQ) did not differ from one another (P ≥ 0.622) in the slope of prediction equations. At the coldest temperature (−2.2°C), though all relationships were highly positive, the highest coefficient of determination was derived from the MIJ system (R² = 0.887), indicating 88.7% of the variation in %IMF is accounted for by the objective output of marbling score. Alternatively, the lowest coefficient of determination was obtained from the EVH device (R²= 0.714), only explaining 71.4% variation in %IMF, which notably was the only system at −2.2°C to not surpass an 80% threshold of explaining the variability in %IMF. The highest coefficient of determination at 3.3°C was obtained from the MEQ system (R² = 0.770), indicating 77% of the variation in %IMF is accounted for by the objective device output of marbling score. Divergently, the lowest coefficient of determination was derived from the MIJ device (R²= 0.687), only explaining 68.7% variation in %IMF, which is completely inverse compared with −2.2°C, wherein the MIJ system reported the highest R² value. The highest coefficient of determination at 8.9°C was obtained from the EV system (R² = 0.694), indicating 69.4% of the variation in %IMF is accounted for by the objective device output of marbling score. Inversely, the lowest coefficient of determination was derived from the MIJ device (R² = 0.552), only explaining 55.2% variation in %IMF, which corresponds with the findings from 3.3°C, in which the MIJ system also had the lowest R² value. The MEQ instrument has a predicted %IMF output in the system that was reported in this study. The following predicted outputs at all temperatures were correlated with actual chemical %IMF. At the coldest temperature (−2.2°C), the correlation coefficient was r = 0.949 (P < 0.001); at the intermediate temperature (3.3°C), the coefficient was r = 0.890 (P < 0.001); and at the warmest temperature (8.9°C), the coefficient was r = 0.780 (P < 0.001). There was a cascading effect indicating that the strongest correlation occurred at the coldest temperature (−2.2°C), followed by the intermediate temperature (3.3°C), and lastly, the warmest temperature (8.9°C), which was the least correlated. These data suggest that colder ambient cooler temperatures will allow for the most accurate %IMF evaluations with the MEQ instrument.

Conclusion: Results indicate instrumental marbling scores are a viable tool in predicting %IMF. Furthermore, the MEQ instrument’s %IMF output provides an accurate prediction for actual %IMF. A deeper understanding of the capability of instrumental cameras to predict %IMF is necessary to determine their accuracy. Additionally, continued comparative evaluations of multiple commercially available and emerging beef camera grading technologies are necessary to determine differences in accuracy and repeatability under standardized conditions.

Funding Source: Funded by the USDA Agricultural Marketing Service (AMS).

Keywords: beef, image analysis, instrument, marbling.

92 Development of a Shelf-Stable Proxy for Camera-Based Grading Systems

Anna G. Hilton* and Jessie C. Morrill, Department of Animal Science, University of Nebraska–Lincoln, Lincoln, NE 68588, USA *ahilton7@unl.edu

Introduction/Objectives: The American Meat Science Association’s US Department of Agriculture (USDA) Grading Committee has identified the need for a device that can be used to verify that various camera grading systems produce consistent readings. To fulfill this need, we developed and characterized a shelf-stable proxy device with the aim that it could be used in place of meat to validate readings across and within grading camera equipment. Our objective was to optimize proxy raw material formulations so that the proxy could be utilized for validating camera readings related to amount of intramuscular fat, ribeye area, 12^th-rib fat thickness, and lean and fat color in camera grading scenarios.

Materials and Methods: The proxy was 3D printed in white epoxy resin and filled with a shelf-stable petroleum derivative. The “lean” and “fat” proxy substances were dyed using organic chemicals that were chosen to imitate beef lean and fat color values, respectively. The proxy color values were assessed using a calibrated chroma meter set to the D65 illuminant (CR-400; Konica Minolta; Ramsey, NJ), which provided CIE color space values (L*, a*, and b*). Proxy dimensions were scaled using 3D print–rendering software and were validated manually with a ribeye dot grid and USDA preliminary yield grade ruler. Proxy intramuscular fat content was quantified in photographs using Image J software. Briefly, photographs were taken of the proxy in a photo studio light box under controlled lighting using a Canon Rebel T3. Photographs were saved in.CR2 format and were converted to.tif files using Adobe Photoshop. The.tif files were then imported into ImageJ and were processed using a series of macros, wherein the output was ribeye area, fat thickness, and percentage intramuscular fat, in pixels, within the proxy “ribeye.” A simple linear regression and Pearson correlation were performed using R (version 4.0) and R Studio (tidyverse version 1.3.0, nlme, version 3.0) to determine the relationship between number of marbling pieces within the proxy and percentage intramuscular fat, in pixels.

Results: The shelf-stable proxy has a ribeye area of approximately 90 cm² and a variable fat thickness that ranges from 1 to 1.5 cm, depending on the exact measurement location. The ribeye area and fat thickness of the proxy can be validated using ImageJ or conventional dot grids or probes. The material selected for the proxy’s ribeye has L*, a*, and b* values of approximately 50, 22, and 13, respectively. The material selected for the proxy’s subcutaneous fat and marbling has L*, a*, and b* values of approximately 80, 0, and 15, respectively. When the number of marbling pieces in the proxy is known and the size of each marbling piece is controlled, the percentage intramuscular fat in pixels is highly correlated and predictable (P < 0.001; r > 0.99).

Conclusion: Although color and moisture properties of beef are extremely difficult to mimic in a shelf-stable object, the proxy developed in this study has objective color values that closely resemble those of fresh beef. The color properties, sizing, and marbling attributes of the proxy can easily be adjusted for specific research needs or industry questions. Our future research will include determining whether the proxy can be recognized and measured by commercial beef grading cameras. Because the proxy is a 3D object, there may also be future opportunities for it to be utilized as a hands-on learning tool for teaching beef grading skills, such as measuring ribeye area and fat thickness with dot grids and probes.

Funding Source: This research was supported by the American Meat Science Association.

Keywords: beef, camera grading, proxy, color.

93 Exudate-Based Microbial Analysis for Monitoring Muscle-Specific Microbial Dynamics During Aging

Maha Abdelhaseib*, Jinkyu Seo, and Yuan H. Brad Kim, Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, USA *maha@purdue.edu

Introduction/Objectives: Microbial spoilage is a significant food waste issue costing the US meat industry millions annually, as consumers reject discolored, odorous, or slimy meat. To reduce losses, the industry needs rapid tools for spoilage assessment and shelf-life prediction. Meat exudate, a nutrient-rich byproduct, shows promise as an analytical matrix, yet its microbial dynamics remain largely unexplored. Postmortem aging is a common industry practice, as it improves meat palatability attributes, particularly meat tenderness. Fresh beef muscles with different background toughness require different aging times. As spoilage extent may differ by muscle type, it is crucial to determine whether these differences are reflected in meat exudate. The objective of this study was to characterize microbial shifts in meat exudate during aging, focusing on muscle-specific spoilage patterns and microbial community changes under spoilage conditions.

Materials and Methods: At 1 d postmortem, pairs of 3 muscles including longissimus lumborum (LL), semimembranosus (SM), and infraspinatus (IF) were collected from 15 beef carcasses (US Department of Agriculture Choice). Each pair was sliced into 8 steaks, vacuum sealed, and aged at 1°C ± 0.2°C (control) or 10°C ± 0.2 °C (spoilage condition) for 1, 14, 21, or 35 d in a temperature-controlled room. After aging, exudate and tissue samples were aseptically collected for microbial analysis, including aerobic plate count (APC), lactic acid bacteria (LAB), Pseudomonas, and Enterobacteriaceae. The beef cuts were displayed under light for 7 d, and instrument color measurements were conducted throughout the display time. Data were analyzed using PROC GLIMMIX in SAS 9.4 with Tukey’s test (P < 0.05) for mean separation.

Results: There was significant interaction between muscle type, aging time, and storage temperatures in all microbial measurements in both tissue and exudate. In particular, muscle-specific effects were observed in APC, LAB, Pseudomonas, and Enterobacteriaceae in exudate, whereas only Pseudomonas and Enterobacteriaceae in tissue showed muscle-specific effects. Briefly, APC and LAB counts increased across all conditions, peaking at 35 d, with significantly higher counts at 10°C. In meat tissue, LAB stabilized after 21 d at 10°C. Similarly, Pseudomonas and Enterobacteriaceae counts significantly increased in both tissue and exudate until day 21, corresponding to the bacterial exponential phase, and then stabilized at day 35, aligning with the stationary phase. Notably, exudate consistently mirrored tissue trends. Muscle-specific effects were evident on day 14 at 1°C, with the highest counts in IF, the lowest in LL, and intermediate levels in SM for both exudate and tissue. No differences were observed at 10°C or in later stages. Display color was significantly affected by the interaction of muscle type, aging time, and storage temperature. The IF muscle had the lowest color stability based on a* and chroma, the LL muscle had the highest, and the SM muscle showed intermediate stability. These variations may be attributed to spoilage bacteria growth, which accelerates myoglobin oxidation, leading to redness loss and discoloration. These findings suggest muscle-specific mechanisms influencing bacterial growth and contributing to muscle-dependent discoloration in beef.

Conclusion: The results of the study found the different extent of spoilage occurred in different beef muscles during aging under spoilage conditions. In particular, beef exudate evaluation demonstrated similar muscle-specific patterns, suggesting its potential as an analytical medium for identifying muscle-specific spoilage trends. Ongoing research aims to profile metabolites in both beef exudate and muscle tissue to determine biochemical signatures associated with muscle-specific spoilage.

Funding Source: US Department of Agriculture (USDA)–Agriculture and Food Research Initiative (AFRI) National Institute of Food and Agriculture (NIFA) (2023-67017) Grant.

Keywords: spoilage, exudate, APC, muscle specific.

94 Prediction of Intramuscular Fat Content of Beef Longissimus Muscle

Kyra L. Elliott¹*, Bucky L. Gwartney², Willy J. Horne², and Jessie C. Morrill¹, ¹Department of Animal Science, University of Nebraska – Lincoln, Lincoln, NE 68588, USA, ²Agricultural Marketing Service, US Department of Agriculture, Washington, DC 20250, USA *kelliott12@unl.edu

Introduction/Objectives: Beef grading camera systems are widely utilized to assist with assignment of US Department of Agriculture Quality Grades to beef carcasses in commercial packing facilities. As imaging methods continue to evolve and new imaging systems emerge, understanding how camera grading measurements align with chemically verifiable measurements will continue to be important. In this study, our objective was to determine percentage fat and moisture values for beef longissimus muscle in comparison to marbling scores assigned by 2 beef grading camera systems. An additional objective was to determine whether an open-source imaging software could be utilized to objectively quantify percentage intramuscular fat in digital images of beef longissimus muscle.

Materials and Methods: Untrimmed beef ribs, oven-prepared (Institutional Meat Purchase Specifications #107; n = 78), representing a range of marbling scores, were obtained from a commercial beef processing facility and were transported to the University of Nebraska–Lincoln. Ribs were collected to represent a range of marbling scores between slight and moderately abundant. Rib subprimals were intentionally not aged prior to the start of the trial to minimize changes in lean color and texture properties between grading in the commercial plant and laboratory analyses. On the day of measurement, the posterior end of each subprimal was refaced, and a 3.81-cm-thick steak was cut. Each steak was scraped to be practically free of bone dust and allowed to bloom for 30 min. The steaks were then imaged with an E+V GigE grading camera, an MEQ grading camera, and a Canon Rebel T3 digital camera. Digital images of the steaks were captured in a photo light studio box equipped with an internal 3500K LED light, providing consistent and controlled lighting conditions. Digital camera images were processed using ImageJ software to quantify percentage intramuscular fat by separating lean and fat pixels within the longissimus muscle. After imaging, steaks were frozen at −20°C until analysis. Steaks were then powdered and assessed for fat and moisture content; to determine fat content, total lipids were extracted in chloroform: methanol, using a modified Folch method. Simple linear regressions and Pearson correlation coefficients were calculated using R (version 4.0) and R Studio (tidyverse version 1.3.0, nlme, version 3.0); relationships were considered significant when P value was less than 0.05.

Results: As expected, chemically extractable fat is positively correlated with E+V GigE and MEQ marbling scores (P < 0.001; r > 0.73), and regression equations had R² values of 0.66 and 0.53, respectively. Chemically extractable fat ranged from 1.75 to 8.60 in our study. The ImageJ model was also highly significant (P < 0.001; r = 0.84) and had an R² value of 0.7. When E+V GigE marbling score is known, the equation for determining percentage extractable fat is equal to: (0.0083 × numeric marbling score) – 0.43. When MEQ marbling score is known, the equation for determining percentage extractable fat is equal to: (0.011 × numeric marbling score) – 2.4. Likewise, the equation for determining percentage extractable fat when percentage of intramuscular fat pixels is determined using ImageJ is equal to: (0.55 × percentage marbling pixels) + 1.4. The MEQ grading camera also estimates percentage intramuscular fat, which was correlated to extractable fat (P < 0.001; r = 0.66), but estimates of percentage intramuscular fat were numerically higher than what was measured chemically. This relationship is reflected in the equation: (0.36 × MEQ percentage intramuscular fat) + 1.6. The R² value for this equation is 0.43.

Conclusion: Beef grading camera marbling scores and ImageJ estimates of marbling can be used to estimate chemically extractable fat content, but users should be aware that marbling estimates from each system are calculated through different mechanisms, which are often proprietary. In this study, even when the same steaks were imaged, different marbling scores resulted. In this study, the range of marbling scores for the E+V GigE camera were 281 through 992, whereas the range in marbling scores for the MEQ camera was 383 to 904. When accurate measurements of intramuscular fat content are needed, chemical extraction should still be utilized. Additional work should be conducted in this area to further optimize equations.

Funding Source: This research was funded by the US Department of Agriculture Agricultural Marketing Service.

Keywords: beef, camera grading, intramuscular fat.

95 Impact of Controlled Atmosphere and Electrical Stunning Coupled With Water Immersion and Air Chilling on Muscle-Specific Meat Quality During Retail Display Storage

Rishav Kumar*, Zahidul Hasan Tushar, Matthew Hughes, Shijinaraj Manjankattil, Matthew Bailey, and Dianna Bourassa, Auburn University, Auburn, AL 36849, USA *rzk0108@auburn.edu

Introduction/Objectives: Animal welfare concerns have resulted in a shift toward controlled atmosphere stunning (CAS) as an alternative to commonly used electrical stunning (ES) for broiler chickens. However, CAS has been shown to result in a more rapid meat pH decline postmortem. Water immersion chilling and air chilling are used to reduce carcass temperature and minimize microbial growth. However, a slower cooling rate for air chilling can result in greater pH decline postmortem. Therefore, we hypothesized that different rates of pH decline in ES and CAS coupled with air or water cooling will impact the muscle-specific effect during retail display storage. Retail displays and lights within cases influence consumer attraction while purchasing meat. However, these lights also enhance light-induced oxidation during retail storage. The objective of this study was to compare effects on pH, color stability, lipid oxidation, drip loss, shear force, and microbial count during retail display storage.

Materials and Methods: The experiment was conducted at Charles C. Miller Jr. Poultry Research and Education Center at Auburn University. For trials, 60 birds were used. Either CAS or ES were conducted, with poststunning procedures adhering to standard industry practices. For ES, birds were removed from their transport crates, shackled, electrical water bath stunned at 20 mA/bird for 12 s, mechanically neck cut, bled for 240 s, hard scalded at 54°C for 160 s, and then defeathered for 35 s. For CAS, birds were stunned in their transport crates by exposure to increasing concentrations of CO₂ within 5 phases from 20% to 85% over the course of 6 min with O₂ added to achieve 21% during the first 90 s. After the CAS process, the same processing parameters as ES birds were used. Following defeathering, carcasses continued through evisceration, and then half of the birds were ice water immersion chilled (IC) for 2 h, and half were air chilled (AC) at 4°C for 3 h, then deboned for each treatment, resulting in 4 treatments: CAS/IC (n = 15), CAS/AC (n = 15), ES/IC (n = 15), and ES/AC (n = 15). This 2 × 2 design resulted in 4 treatments defined as CAS/IC, CAS/AC, ES/IC, and ES/AC. The skinless breast fillets and boneless, skinless thighs were weighed, sealed in a zip-top bag, and placed on ice within a cooler for subsequent evaluation of proximate analysis, pH, color (L*, a*, b*, hue, chroma), lipid oxidation (mg MDA/kg), drip loss (%), shear force (N) and aerobic bacteria levels (log 10 CFU/mL) at 24 h postdeboning for day 0 analysis. Fillets and thighs used for retail light display (3,000 lux) were placed into Styrofoam trays, overwrapped with polyvinyl chloride film, and placed into simulated retail display storage for 7 d. On day 7, samples were analyzed for pH, color, lipid oxidation, drip loss, shear force, and aerobic bacteria. The experiment design was a completely randomized design (n = 15 per treatment). All data were analyzed using the GLIMMIX procedure in SAS, with significance at P < 0.05.

Results: There was no difference between treatments for protein in fillets, whereas CAS fillets had the least moisture percentage (P < 0.001). Both stunning and chilling methods impacted fillet and thigh pH and color after deboning. For fillets and thighs, CAS had higher pH than ES (P < 0.001). For fillets, hue was lower and chroma was higher for CAS than ES (P ≤ 0.034). However, CAS thighs were lighter, yellower, and higher hue than ES thighs (P ≤ 0.044). IC fillets had higher pH than AC (P < 0.001). IC resulted in higher thigh pH, lightness, and hue than AC (P < 0.001). Both fillets and thighs had interactions between stunning and chilling methods for redness. Fillets from CAS/IC were the reddest (P = 0.004), whereas thighs from ES/AC were the reddest (P < 0.001). After 24 h, AC fillets had higher chroma than IC (P = 0.018). There was an interaction between stunning and chilling for fillet pH in which ES/AC was the highest and CAS/AC was lowest (P < 0.001). ES thighs were lighter than CAS thighs (P = 0.025), and both redness and hue had stunning and chilling interactions. CAS/AC thighs were redder than ES/AC thighs (P = 0.025), whereas CAS/IC had higher hue than CAS/AC (P = 0.016). CAS fillets had less lipid oxidation than ES (P = 0.013), but thighs had more lipid oxidation from CAS than ES (P = 0.033). Thighs also had higher lipid oxidation from IC compared with AC (P = 0.001). Thigh drip loss was higher for CAS than ES (P = 0.019) with no difference in fillets. ES fillets had lower shear force (P < 0.001) compared with CAS, whereas IC had lower shear force than AC (P = 0.023). After the 7 d of retail display, CAS/AC had the highest pH (P < 0.001), whereas ES/IC thighs had greater pH (P < 0.001). There was no effect of stunning and chilling on fillet and thigh drip loss. For color stability, ES/IC breast fillets had greater L* (P < 0.001), and CAS/AC had lower b* (P = 0.009), whereas CAS/AC had more chroma (P < 0.001). However, CAS/AC thighs had a greater a* (P = 0.007), whereas CAS/IC had more hue value (P = 0.006) after display storage. Lipid oxidation was greater (P = 0.016) in AC chilled fillets with no difference in stunning method. There was no significant effect of stunning or chilling in thighs. AC fillets had higher (P = 0.004) shear force after retail display storage, whereas ES/AC thighs had greater (P = 0.027) shear force. On day 0, breast fillets had no significant effect of stunning as well as chilling on aerobic plate counts, whereas after 7 d, CAS/IC had the lowest aerobic plate counts (P = 0.002).

Conclusion: This study examined the impact of broiler breast fillet and thigh stunning and chilling combinations at 24 h and 7 d of storage on poultry meat quality during retail display. For breast fillets, CAS combined with IC (CAS/IC) proved optimal, yielding higher pH, reduced lipid oxidation, lower shear force, and improved microbial stability, alongside enhanced color retention (lower hue, higher chroma). In contrast, thighs processed via CAS exhibited higher lipid oxidation and drip loss, suggesting ES paired with AC (ES/AC) as preferable for minimizing oxidative degradation, although CAS/AC thighs demonstrated superior color attributes (higher redness and hue). Future research must focus on metabolic profiles of CAS/ES coupled AC/IC chilling methods that provides more valuable insights about muscle-specific effects of stunning and chilling during retails display storage, and along with this, more research could explore whether informing consumers about the stunning methods influences their acceptance in sensory attributes between electrical- and gas-stunned chicken.

Funding Source: This work was supported by the United States Department of Agriculture Agricultural Research Service, Athens, GA (project number 6040-42440-001-011-S); the Alabama Agricultural Experiment Station; and the Hatch Program of the National Institute of Food and Agriculture, US Department of Agriculture.

Keywords: quality, stunning, retail, chilling, muscle-specific.

96 Effects of a High-Sugar or High-Protein Diet on Carcass Composition, Proximate Composition, and Shelf-Life Indicators in Biomedical Swine Models

Shelby E. Raber¹*, Emily R. Barr¹, Kemsley Gallegos¹, Jeremy L. Burkett², Hannah C. Cunningham-Hollinger¹, and Cody L. Gifford¹, ¹Department of Animal Science, University of Wyoming, Laramie, WY 82071, USA, ²School of Science, Department of Agriculture, Casper College, Casper, WY 82601, USA *sraber1@uwyo.edu

Introduction/Objectives: The objective of this study was to compare the impacts of feeding a Western-style diet (WSD) or a high-protein (HP) diet adapted for swine based on human dietary macronutrient targets to evaluate the impact of diet on muscling and body composition, crude fat and muscle chemistry attributes, and objective muscle color to better understand the impact of diet on physiological growth during specific growth phases using swine as a biomedical model.

Materials and Methods: Duroc × Landrace × York crossbred pigs were randomly assigned to dietary treatments during 2 phases of the study. During phase 1, pigs (n = 30) started acclimating to an adapted HP or WSD at a mean body weight of 45 kg and remained on each diet for 8 wk. After 8 wk on each diet, a subsample (n = 5/treatment group) were harvested at the University of Wyoming Meat Laboratory to evaluate physiological impacts of diet. During phase 2, remaining pigs were assigned to diets consisting of 8 additional weeks of HP, 8 additional weeks of WSD, HP to WSD, or WSD to HP. Following harvest, carcass quality metrics, muscle tissue samples, muscling metrics, empty organ weights, and adipose tissue deposition at the 1st, 3rd, 5th, 7th, 10th, and lumbar regions were collected. Objective color measurements (L*, a*, b*) were measured during a 7-d display period. Loin samples fabricated into 2.54-cm-thick portions were frozen for subsequent analysis and frozen. Specified loin samples were homogenized and stored at –80°C for muscle chemistry analysis, including proximate analysis. R statistical software was used to analyze data. The lm function from the lme4 package was used to evaluate the fixed effects of diet. Significant treatment means were separated with Tukey’s adjusted pairwise comparisons using the emmeans package. An α less than or equal to 0.05 was used to determine significant effects and pairwise comparisons.

Results: Diet did not impact (P > 0.05) final live weight in either phase 1 or phase 2. During phase 1, pigs fed the WSD had greater hot carcass weight (HCW; P = 0.0205) than pigs fed the HP diet. There was no impact of diet on HCW during phase 2. Measurements of loin eye area and 10th-rib fat thickness were not impacted (P > 0.05) by diet during phase 1 or phase 2. During phase 1, pigs fed the WSD for 8 wk had greater last-rib fat (P = 0.001) than other treatments, but diet did not impact (P > 0.05) this fat metric in phase 2. Loin samples from pigs fed HP for 8 wk followed by WSD for 8 wk and pigs fed the HP diet for 16 wk had greater (P = 0.0164) redness values. Crude fat was greater (P = 0.0266) among loin samples from pigs fed a WSD for 16 wk than pigs that started on a HP diet and switched to a WSD diet during phase 2.

Conclusion: A WSD impacts composition of muscle and fat metrics, muscle chemistry, and objective color differences in biomedical swine during prepubertal and postpubertal growth phases. Additional research is needed to determine whether major impacts earlier in the animals’ growth phases program composition and health outcomes more than surrounding puberty.

Funding Source: Wyoming IDeA Networks of Biomedical Research Excellence (INBRE) Network for Biomedical Research Excellence.

Keywords: diet quality, swine, biomedical.

97 Correlations Between Different Shear Devices in Measuring Texture of Various Pork Loins

Marta Rodríguez-Fernández¹, Isabel Revilla¹, Chaoyue Wang², Ana M. Vivar-Quintana¹, and Shai Barbut²*, ¹Universidad de Salamanca, Zamora, Spain, ²University of Guelph, Guelph, Canada *sbarbut@uoguelph.ca

Introduction/Objectives: Among the available methods for measuring meat texture, the Warner-Bratzler shear force (WBSF) test has historically been the most widely used worldwide because of its reputation for evaluating tenderness. However, the National Cattlemen’s Beef Association currently recommends the slice shear force (SSF) test, as it provides faster analysis. In this method, samples are shared just after cooking, allowing for a more precise identification of tenderness differences. In recent years, alternative techniques have emerged, including the Meullenet-Owens razor shear (BMORS) test, recognized as the fastest, precise, and simplest method for evaluating poultry meat tenderness. However, despite its advantages, its application to pork meat remains limited. This study aimed to compare the effectiveness of new methodologies, such as BMORS, with traditional methods (WBSF and SSF) in evaluating meat tenderness across different pork meat sources; establish correlations between the parameters obtained; and determine the viability and accuracy of evaluating pork loin meat.

Materials and Methods: A total of 342 pork loin samples from 13 different groups were selected. The animals analyzed represent different breeds, management systems, and diets. Pork loin samples between T9 and T13 (longissimus thoracis), with a thickness of 3.5 cm, were kept at 4°C for 72 h, and then vacuum packed, frozen, and stored at −20°C for up to 3 mo. Samples for hot analysis were grilled (plate-grill KGJ442, GGM Gastro Inter., Ochtrup, Germany) preheated to 200°C. When the center reached 40°C, the samples were turned over until reaching 68°C, removed from the grill, and allowed to reach 70°C internally. Samples were also analyzed at refrigerated temperature 4°C after 6 h of storage. For WBSF analysis, 6 cylindrical portions (1.27-cm diameter) were obtained parallel to the muscle fiber direction and later sheared in the perpendicular direction of the fibers using a 2.97-mm-thick Warner-Bratzler blade. For SSF analysis, a kit was used to cut 2 portions from the each slice, which were sheared using a flat blade (70 mm wide; 1,168 mm thick) with a half-round beveled cutting edge. BMORS analyses were performed at 6 different points along the entire slice surface with a blunt blade (9 mm wide; 0. 42 mm thick) positioned at 90° to the surface. Both WBSF and SSF blades were attached to a TA-XT2i texturometer (Texture Technologies, Hamilton, MA) using a crosshead speed of 2 mm/s, whereas BMORS used a crosshead speed of 10 mm/s. WBSF and BMORS were performed on both hot and room-temperature samples and SSF only on hot samples. The values recorded were shear force, which is the maximum force recorded (N), and work, which is the area under the force-strain curve (N × mm) from the start of the test to the maximum force. Correlations between the different parameters were studied using a 2-tailed Pearson significance correlation.

Results: A pairwise Pearson correlation analysis was carried out to evaluate the significant relationships between texture parameters obtained by different measuring devices and probes. First, the maximum force obtained by the SSF device (only applied to hot grilled samples) showed a significant correlation with the force obtained after WBSF test of both hot samples (0.256; P < 0.01) and cold samples (0.329; P < 0.01). Furthermore, SSF work showed significant correlations with WBSF work; for cold cooked samples (0.678; P < 0.01) and hot grilled samples (0.504 P < 0.01), the coefficient values were higher than those found for the force values. As for the WBSF probe, significant correlations were identified for the maximum force of cold samples with that of hot samples (0.362, P < 0.01) and also between hot samples WBSF work and cold samples WBSF work (0.663, P < 0.01). This suggests a correlation resulting from the mechanical resistance of the meat fibers’ weave when evaluated at different temperatures. Both methods captured related mechanical characteristics of the sample, although with different sensitivities depending on the temperatures, as was also previously reported by other studies. The results obtained by using the BMORS probe on hot samples showed positive correlations between force and the WBSF parameters (force and work) in both cold samples (0.279 and 0.268; P <0.01) and hot samples (0.225 and 0.369; P < 0.01). Similar correlations were found for both force (0.264; P < 0.01) and work (0.264 and 0.238; P < 0.01) obtained for the SSF test. The BMORS work showed the same type of positive correlations—that is, with both force and work obtained after applying WBSF and SSF but with lower Pearson coefficients values. The BMORS test applied to cold cooked samples showed significant and higher correlations for both BMORS force and work, with the work of other test. Thus, the correlations with the WBSF work of cold samples were 0.411 and 0.649 (<0.01) for BMORS force and BMORS work respectively, whereas for the WBSF work of hot samples, the values were 0.417 and 0.489 (P < 0.01) for force and work, respectively. The correlation values with the SFF work were: 0.513 (P < 0.01) with force and 0.681 (P < 0.01) with work. Overall, the correlations were higher for BMORS work than for BMORS force in all cases. The BMORS results indicate a strong association between BMORS texture parameters and other shear test parameters, but under specific thermal conditions.

Conclusion: Results of the study indicated that methods of sample preparation and probe used have a determining influence on the evaluation of meat texture. The BMORS test applied to cold, cooked samples showed the strongest correlations for both force and work with other texture parameters. This suggests their suitability for evaluating the mechanical force of the meat tissue under these conditions. On the other hand, when the BMORS test was performed on hot samples, fewer significant correlations were found. Having established correlations between SFF and BMORS in cold samples meant that they provide similar information and could be used as an alternative for texture evaluation, especially because of their speed and simplicity. This study showed the possibility of optimizing the selection of instrumental techniques according to available analytical conditions.

Funding Source: Universidad de Salamanca, Zamora, Spain.

Keywords: SSF, BMORS, WBS, pork, texture.

98 Influence of Retail Display Case Conditions and Packaging Types on Palatability of Fresh Beef Steaks From 3 Different Muscles

Stephanie Shimer¹*, Sarah Shoup¹, Elizabeth Neal², Janeal Yancy¹, Morgan Denzer³, Derico Setyabrata¹, Jerrad legako², Kelly Vierck¹, ¹Department of Animal Science, University of Arkansas, Fayetteville, AR 72701, USA, ²Department of Animal and Food Science, Texas Tech University, Lubbock, TX 79409, USA, ³Department of Food Science, University of Arkansas, Fayetteville, AR 72701, USA *sshimer@uark.edu

Introduction/Objectives: Sustainability is becoming an increasing concern to both retailers and consumers of fresh meat products. Energy efficiency can be improved by the addition of doors to fresh meat retail display cases. However, little is known regarding the effects of retail display cases on beef quality attributes, particularly palatability. The objective of this study was to determine the influence of retail case type, muscle, and package scheme on consumer perception of tenderness, juiciness, and flavor of fresh beef steaks.

Materials and Methods: Paired beef striploins, eye of rounds, and top sirloin butts were selected from US Department of Agriculture (USDA) Low Choice carcasses (n = 20). Subprimals were wet aged for 14 d in dark storage. Following aging, subprimals were fabricated into 2.54-cm steaks (n = 18 steaks per subprimal), representative of the gluteus medius (GM), longissimus lumborum (LL), and semitendinosus (ST) steaks. Each steak was randomly assigned to 1 of 3 packaging schemes, including modified atmosphere packaging (MAP), polyvinyl chloride overwrap (OW), or vacuum (VAC). MAP steaks were immediately packaged into a traditional PVC overwrap tray and stored in a mother bag (31.1% CO₂, 0.4% CO, and 68.5% N). OW steaks remained in vacuum packaging until further processing before retail display. Steaks were transported under refrigerated temperatures (0–4°C) to the University of Arkansas Red Meat Abattoir (Fayetteville, AR). Steaks were aged for an additional 7 d in the dark (0–2°C) before further processing. After storage, OW were repackaged into polyvinyl chloride overwrap, and MAP steaks were removed from mother bags. All steaks were randomly assigned to either an open-fronted multideck case and a closed-door case. After the retail display period, all steaks designated for consumer panel analysis were vacuum packaged and frozen. Steaks were transported to Texas Tech University while frozen (<0°C) for consumer analysis. The samples were cooked on a clam-shell grill to an internal temperature of 71°C and cut into 2.54 × 1 × 1 cm³ cubes. Panelists (n = 360) were asked to rate tenderness, juiciness, flavor, and overall liking on a scale of 0 (dislike extremely) to 100 (like extremely). Panelists determined acceptability of palatability traits and overall liking for consumed samples. An exit survey was conducted to collect consumer demographics and determine the importance of purchasing traits in fresh beef retail scenarios. The study design was a split-split plot design, in which muscle, packaging type, and case type served as fixed effects. Collection round and time were incorporated into the model as random effects. Data were analyzed using PROC GLIMMIX. Significance was declared at P value less than 0.05. Least-squares means were separated using F-Test.

Results: No significant 2-way or 3-way interactions were observed for evaluation or acceptability of palatability traits analyzed. Tenderness, juiciness, flavor, and overall liking scores were all significantly influenced by muscle effects (P < 0.0001). LL steaks were rated as juicier, more flavorful, more tender, and higher in overall liking compared with ST or GM steaks (P < 0.0001). No significant case or packaging main effects were observed for all palatability traits analyzed. However, there was a tendency for OW steaks to exhibit lower scores than VAC or MAP steaks (P = 0.059). There was a significant packaging effect for the acceptability of the palatability traits. VAC steaks were rated as the most acceptable in flavor compared with MAP and OW steaks (P < 0.0001). Similarly, a significant muscle effect was observed, exhibiting greater juiciness, tenderness, and overall liking acceptability in LL steaks regardless of retail display case or packaging scheme. The flavor acceptability of LL and GM was not statistically different, but both were more acceptable than ST steaks. ST steaks were determined to be the least acceptable in flavor, juiciness, tenderness, and overall (P < 0.0001). Consumers identified price, color, USDA quality grade, and steak size as critical factors in purchasing fresh beef. Among these, color was the most significant purchasing trait for consumers. Grass/grain feeding claims and packaging type were equally rated as the least important purchasing factors.

Conclusion: These data indicate that retail case type does not play a role in beef palatability. Packaging scheme may impact flavor acceptability for consumers but does not impact juiciness, tenderness, or overall liking. The current results indicated that consumer purchase intent is driven by a myriad of factors, including visual appearance, inherent muscle properties, and USDA quality grade. Lean color, price, USDA quality grade, and size remain incredibly important traits to modern consumers. This knowledge may be used to improve sustainability of modern fresh beef retail environments by decreasing energy use in retail display cases.

Funding Source: Research coordinated by the National Cattlemen’s Beef Association, a contractor to the Beef Checkoff.

Keywords: muscle, packaging, retail case, consumers, retail display.

99 Impact of Vinegar and Fermented Onion Juice on the Quality and Shelf Life of Fresh Pork Breakfast Sausage

Emily Little¹, Isa Maria Reynoso¹*, Ryen Comey¹, Sawyer Wyatt Smith¹, Li Zhang¹, Brian Smith², Xue Zhang¹, and Wes Schilling¹, ¹Mississippi State University, MS 39762, USA, ²Hawkins Inc., Roseville, MN 55113, USA *iar57@msstate.edu

Introduction/Objectives: The demand for clean-label meat products has increased interest in using natural alternatives to synthetic preservatives in fresh pork breakfast sausage. This study evaluated the effectiveness of dry vinegar (DV) and fermented onion juice (FOJ) in extending pork breakfast sausage shelf life through microbiological and instrumental analysis, lipid oxidation assessment, and sensory evaluation over a 9-d refrigerated storage period.

Materials and Methods: A randomized complete block design with 3 replications was used to evaluate the efficacy of DV and FOJ at lengthening the shelf life of pork sausage. Fresh pork shoulders and hams (24 h postmortem) were coarsely ground, and then portioned into 4 treatments (7 kg batch/treatment): control (no antimicrobial), 0.5% FOJ, 0.5% DV, and a combination (CMB; 0.25% each). Each sausage treatment was then stuffed into casings, frozen, and then sliced into 1.27-cm-thick patties before being placed on trays (3 patties/tray), overwrapped in PVC film, and stored at 4°C under fluorescent lighting (F32T8/SPX35/ECO2) to mimic retail display conditions for 9 d. For all treatments, 4 trays of each treatment were randomly selected at each of the 4 time points (days 1, 4, 7, and 9) for the following analyses. Microbiological analyses included total aerobic bacteria, psychotropic bacteria, lactic acid bacteria as well as yeast and mold, wherein each treatment was tested in duplicates on each sampling day. Instrumental analyses included color (L*, a*, b*; CM-600d, Konica Minolta Inc., Tokyo, Japan), pH (HI 98163, Hannah Instruments Inc., Woonsocket, RI), and water activity (Aqualab 4TE: Pullman, WA), in which 3 patties for each treatment on each day were used for analysis. Lipid oxidation for each treatment on each day was assessed using thiobarbituric acid reactive substances (TBARS) method (Cayman Chemical TBARS Assay Kit protocol) for quantification of lipid oxidation products. Descriptive sensory analysis of raw and cooked patties was performed by trained panelists (n = 4–6) evaluating aroma, appearance, and flavor attributes as well as degree of differences compared with a typical breakfast sausage. The raw patties were evaluated for aroma (sour, oxidized, rancid, and off-notes) and appearance (darkness and slimy). For cooked patties, the same attributes in raw patties were evaluated, but with the inclusion of flavor intensity and spoilage aroma and flavor. Proc MIXED was used to analyze the effect of treatment and day on the analyzed attributes, with replication considered as a random factor. Tukey’s honestly significance difference test was used to separate means when differences occurred among treatments (P < 0.05).

Results: Microbiological analysis indicated that DV and CMB (P < 0.05) reduced aerobic and psychotropic bacterial counts by days 7 and 9 in comparison to the control and FOJ. The CMB also exhibited the lowest lactic acid bacteria counts (P < 0.05) by day 9. Yeast counts increased over time with no differences (P > 0.05) across treatments on each day of testing, reaching approximately 7 log CFU/g by day 9. Water activity and pH remained stable across treatments and throughout the storage, suggesting minimal impact of DV and FOJ on meat chemistry. Lipid oxidation did not differ among treatments (P > 0.05). Instrumental color analysis revealed a significant decline in redness (a* values) over time (P < 0.05) for the control and DV, whereas FOJ and CMB exhibited a more stable color profile, with no significant decline (P < 0.05) in redness by day 9. Sensory analysis of raw patties treated with CMB demonstrated less (P < 0.05) oxidation and off-note aroma scores in comparison to the control by day 9. This suggests that DV and FOJ together may mitigate spoilage-associated sensory changes given that the usage levels are optimized for shelf-life extension of breakfast sausages. For cooked patties, no differences existed among treatments in terms of sour aroma, flavor intensity, or oxidized flavor by day 7 (P > 0.05). This illustrates that the inherent acidity of either DV or FOJ (alone or in combination) did not influence the aroma of the cooked patty. Cooked patties treated with DV and CMB received lesser (P < 0.05) ratings for spoilage and degree of differences than the control throughout the shelf-life period.

Conclusion: These findings suggest that DV, alone or combined with FOJ, may improve microbial stability and sensory quality while supporting clean-label trends. This research is particularly relevant, as the demand for natural alternatives to synthetic preservatives continues to increase and can provide insight into the effectiveness of clean-label ingredients for maintaining meat quality and stability. Future studies will include gas chromatography–mass spectrometry to analyze volatile compounds associated with sensory characteristics of pork sausage during shelf life. Microbial species found on pork sausage samples during shelf life may also be identified to better elucidate the antimicrobial mechanisms of the clean-label preservatives.

Funding Source: National Pork Board.

Keywords: sausage, vinegar, onion, quality, sensory.

100 Determination of Consumer Purchase Thresholds for Discoloration of Beef Steaks in Retail Display

Stephanie L. Witberler¹, Lauren M. Frink¹, Mason J. Prester¹, Chesney A. Effling¹, Erin S. Beyer¹, Jessie L. Vipham¹, Morgan D. Zumbaugh¹, Michael D. Chao¹, Lindsey N. Drey², and Travis G. O’Quinn¹, ¹Kansas State University, Manhattan, KS 66506, USA, ²Cargill, Wichita, KS 67214, USA *switberler26@ksu.edu

Introduction/Objectives: Consumers view meat color as one of the most important factors influencing the purchase of beef at retail. As meat discolors, consumers’ likelihood to purchase decreases. Therefore, the objective of this study was to determine and develop predictive models for consumer purchase likelihood based on objective measures of steak redness and discoloration and to identify thresholds for consumer purchase of beef striploin steaks using objective measures of beef quality.

Materials and Methods: The study was designed in 2 phases. Phase 1 required consumers to evaluate steak samples from various days of display ranging in discoloration from fresh to 100% discolored. Phase 2 required consumers to evaluate samples from the same day of display with similar discoloration. For both phases, commercially packaged steaks were procured from a major beef processor in a case-ready format, identical to packages that would otherwise be displayed and sold at retail. Steaks were received in packages of 2 steaks, so 1 steak was covered with a piece of black matte tape so only 1 steak was visible. Steaks were all the same US Department of Agriculture quality grade (upper 2/3 Choice) and were packaged and stored identically prior to the simulated retail display period. For each phase, steaks were removed from their mother bag, placed in coffin-style retail cases, and displayed under florescent lights for the preplanned display period (0–14 d) in order to create differences in both steak color and discoloration. Consumers (N = 200 for phase 1; 176 for phase 2) evaluated steaks for overall appearance liking and identified whether they would purchase the product (yes/no) if it was fully priced as well as if it was sold at a discount. Additionally, numerous objective color measures (L*, a*, b*, chroma, hue angle) were assessed on each sample, and each was evaluated by a trained descriptive sensory panel for overall redness, with 100 being bright cherry red and 0 being extremely dark red, percentage discoloration (0–100%), and external fat color, with 100 being bright white and 0 being brownish-white. All data were analyzed using SAS with α set at 0.05.

Results: In both phases of the study, all objective measures evaluated were predictors (P < 0.05) of consumer purchase intent. The predictive models accounted for 30% to 78% of the variation in consumer purchase intent for steaks sold at full price and 27% to 72% of the variation when sold at a discount for phase 1. In phase 2, the models were less predictive, with models only accounting for 11% to 57% of the variation in consumer purchase likelihood in both full-priced and discounted samples. a* value and trained sensory panel discoloration scores were some of the best predictors evaluated. These models showed that even minimal discoloration has a large impact on consumer purchasing likelihood, with steaks that had 12% to 22% discoloration only having a 50% chance of being purchased at full price for phases 1 and 2, respectively. When steaks were discounted, consumers were more tolerant of discoloration. In phase 1, steaks with 35.8% discoloration had a 50% chance of being purchased, and in phase 2, steaks with 56.8% discoloration had the same likelihood. Similarly, a* values were lower at each threshold of purchase likelihood when steaks were discounted. For phase 1, a* values of 25.3, 29.9, and 34.4 were associated with a 50%, 75%, and 90% likelihood of purchase, respectively, compared with 20.3, 25.8, and 31.3 when discounted. In phase 2, a* values of 23.6 and 34.2 were associated with a 50% and 75% likelihood of purchase at full price, whereas discounted thresholds dropped to 15.9 and 25.5 for a*. Pearson correlation coefficients supported the importance of redness and discoloration. In phase 1, a* was highly correlated with trained panel redness scores (r = 0.90) and consumer appearance scores (r = 0.87). These relationships weakened in phase 2, particularly between a* and consumer appearance scores (r = 0.69), likely because of the uniform display time. Other color measures (b*, chroma, fat color) showed similar patterns with stronger associations in phase 1. Linear regression models showed all objective measurements were predictors of consumer appearance ratings (P < 0.05). In phase 1, models explained 32% to 80% of the variation in appearance scores; in phase 2, they explained only 22% to 48%. The a* value explained 76% of the variation in phase 1 and 48% in phase 2. Trained panel discoloration scores accounted for 59% and 37% of variation, respectively. As redness increased, consumer appearance scores improved; as discoloration increased, scores declined.

Conclusion: The a* values were one of the most predictive measures, accounting for 64% of the variation in consumer purchase intent when steaks are sold at full price. Consumers expected steaks to be almost completely free of discoloration to be willing to purchase, as steaks with just 12% discoloration were associated with only a 50% likelihood of purchase. Any perceived defect would likely result in a decrease in likelihood to purchase. During phase 2, when all steaks evaluated by consumers were similar in appearance, consumers were more selective than in phase 1 when steaks had a wide range of variation. These findings offer valuable insights into the impact of discoloration on consumer purchase decisions using objective measurements and can help retailers reduce waste, improve sales, and better meet consumer expectations.

Figure 1.

Probability of a consumer purchasing a beef striploin steak based on a* value and pricing—phase 1.

Funding Source: Research coordinated by the National Cattlemen’s Beef Association, a contractor to the Beef Checkoff.

Keywords: beef, color, consumer, discoloration, retail.

101 The Effects of Sodium Bisulfate, an Inorganic Acid, Used as a Short-Duration Dip on the Quality and Shelf Life of Ground Beef

Mack P. Myer¹, Josie N. Hernandez¹, Emily R. Barr¹, Cody L. Gifford¹, Dana K. Dittoe¹, and Christina Ovall², ¹Animal Science Department, University of Wyoming, Laramie, WY 82071, USA, ²Jones-Hamilton Co., Walbridge, OH 43465, USA *ddittoe@uwyo.edu

Introduction/Objectives: Multiple factors affect the microbial load present within ground beef, such as the age, season of the year the animal is slaughtered, lymphatic system, and the combination of multiple within 1 package. Therefore, it is important to implement antimicrobial interventions to reduce the microbial load and extend shelf life. In the current study, the objective was to determine the effect of sodium bisulfate (SBS), an inorganic acid, when used as a short-duration spray on beef trim on the subsequent physical and chemical quality of ground beef over a 28-d shelf life. The present study hypothesizes when SBS is used on beef trim as a short-duration dip, the overall pH, objective color, and shelf life would be unaffected.

Materials and Methods: In the present study, beef trim was fabricated from multiple beef carcasses and separated into 7 batches, each assigned to 1 of the 7 antimicrobial treatments: no treatment (NT), tap water (TW), SBS (3% wt/vol), Assist (pH 1.1), lactic acid (LA, 4% wt/vol), peracetic acid (PAA, 500 ppm), and the combination of SBS + PAA. Samples were dipped for 10 s into respective treatments and removed to drip for at least 2 min on sanitized smoking racks. After treatment, trim was ground, weighed, and formed into 1-lb bricks; vacuum packaged; and stored at 4°C under continuous LED light to simulate retail display conditions for 28 d. Ground beef quality was evaluated on days 1, 7, 14, 21, and 28 for pH, objective color, and shelf life. Additionally, homogenates were collected to assess the microbial ecology over 28 d. Samples were aseptically opened and allowed to bloom for 30 min prior to examining objective color and pH. For microbial analysis, 50 g of ground beef was homogenized with 150 mL of neutralizing buffered peptone water in sterile filter bags for 2 min at 200 rpm. Homogenized samples were serially diluted with 0.1% buffered peptone water, plated using pour and dot plating techniques on respective media, and incubated to enumerate common spoilage indicator microorganisms, including aerobic mesophiles, Enterobacteriaceae, lactic acid bacteria (LAB), Pseudomonas spp., and psychrotrophs. Bacterial counts were recorded as CFU/g, Log10 transformed. Quality and microbial date were analyzed using a linear mixed effect model with pairwise differences determined by day using Tukey’s honestly significant difference and significance determined at P value less than 0.05 (mixed effect = day).

Results: There was no treatment by day interaction on ground beef pH (P > 0.05). There was a treatment by day interaction on objective color and microbial counts (P < 0.05). There was a treatment effect on L*, a*, and b* within each sample day (P < 0.05). Samples treated with SBS + PAA did not differ from NT, PAA, and SBS in L* values within each day (P > 0.05), except day1 differed from NT and day 28 differed from SBS (P < 0.05). Additionally, no antimicrobial treatment was lighter than TW or darker than NT (P < 0.05). The a* values of samples treated with SBS were consistent to samples treated by SBS + PAA within each sample day and, as well, PAA was comparable to NT within each day (P > 0.05). The b* values were similar between SBS + PAA, LA, Assist, and SBS (P > 0.05), except on day 28, when SBS + PAA differed from Assist (P < 0.05). Additionally, NT- and TW-treated samples had comparable b* values within each day, and SBS was similar to LA and Assist (P > 0.05). There was a treatment effect on microbial shelf life within each sample day (P < 0.05). Samples treated with SBS and LA had higher aerobic mesophile levels on days 1 and 7 (P < 0.05). By days 21 and 28, NT and TW samples increased and surpassed spoilage (>7 log CFU/g), whereas SBS and PAA were below spoilage (6.61 and 6.56 log CFU/g on day 28). Enterobacteriaceae levels among LA- and SBS-treated samples (2.0–2.20 log CFU/g) were higher than all other treatments (∼1.8 log CFU/g), except on day 1, when LA-treated ground beef had higher levels (3.92 log CFU/g) than all other treatments (P < 0.05). LAB were greater among LA and SBS than all other treatments on day 1 (3.92 and 3.63 log CFU/g) (P < 0.05); however, by day 7, SBS maintained LAB levels comparable to PAA (2.15 and 2.11 log CFU/g) (P > 0.05). By days 21 and 28, NT and TW samples spoiled (> 7 log CFU/g), whereas SBS + PAA– and Assist-treated samples were not different from one another and did not spoil (5.25 and 5.27 log CFU/g) (P > 0.05). Pseudomonas spp. recovered from Assist and SBS, PAA, and SBS + PAA, and SBS- and LA-treated samples were not different on any day (P > 0.05). On days 1, 14, and 21, psychrotroph levels recovered from LA-, Assist-, SBS-, and SBS + PAA–treated samples were not different (P > 0.05). On day 7, psychrotroph levels of SBS + PAA–treated samples were lower than other samples (P < 0.05), and on day 28, SBS-treated samples were not different than PAA-treated samples (P > 0.05).

Conclusion: Antimicrobial treatments affected color stability and microbial spoilage over 28 d (P < 0.05). However, SBS treatments (SBS and SBS + PAA) were generally comparable to industry controls, Assist and LA, in color values, with SBS treatments not differing from PAA in lightness (L*). Spoilage was indicated by aerobic mesophiles, LAB, and psychrotophic bacteria on NT and TW samples by day 28. All other treatments showed an extended shelf life, maintaining microbial levels below 7 log CFU/g for all microorganisms evaluated. Throughout shelf life, SBS, PAA, LA, and Assist had comparable recovered shelf-life microbial indicator levels. These results indicate SBS may be an effective alternative antimicrobial for extending the shelf life of ground beef.

Funding Source: We acknowledge the in-kind support of chemical solutions from Safe Foods Chemical Innovations and Jones-Hamilton Co.

Keywords: ground beef, sodium bisulfate, spoilage.

102 Consumer Evaluations and Warner-Bratzler Shear Force of Food Service Tenderloin Steaks From 6 Different Sources

Lauren T. Lee^*, Sage L. Boleman, Spencer B. Tindel, Kerri B. Gehring, and Jeffrey W. Savell, Texas A&M AgriLife Research, Texas A&M University, College Station, TX 77840, USA *lee99@tamu.edu

Introduction/Objectives: Tenderloins are often one of the highest-priced subprimals and steaks in the marketplace because of their tenderness and flavor. Consequently, food service establishments often seek alternative cuts that provide comparable eating experiences to US Department of Agriculture (USDA) Choice and USDA Prime steaks but at a lower price point. It is of interest to determine whether incorporating additional beef tenderloin sources into the US food service sector could provide a more cost-effective tenderloin option for consumers while still delivering a satisfying eating experience. This study evaluated alternative tenderloin sources that are either readily available to meet consumer demand or offered at a lower price point than what is found in the traditional US market. The study included 6 different sources of tenderloin steaks and aimed to determine the effect of source on consumer sensory ratings and Warner-Bratzler shear force (WBSF) objective tenderness.

Materials and Methods: Tenderloins were sourced from 6 carcass types: (1) USDA Choice carcasses, (2) USDA Select carcasses, (3) white-fat cow carcasses, (4) yellow-fat cow carcasses, (5) Uruguayan carcasses, and (6) Australian carcasses. Twenty-seven Institutional Meat Purchase Specifications #190A tenderloins were collected from each source type (n = 162). Each tenderloin was fabricated into 6 steaks (n = 162 steaks per source). Three steaks were used for sensory evaluation, 2 steaks were used for WBSF testing, and 1 steak was held in reserve. All steaks were cooked on a preheated (∼177°C) Star International Commercial flat-top grill (Max Model 536TGF; St. Louis, MO). After placing on the grill, steaks were flipped when internal temperature reached 35°C and then cooked to a final temperature of 70°C. Internal steak temperatures were monitored using digital thermometer probes (ThermoWorksThermoPop, American Fork, UT). For each steak, pre- and postcook weights were recorded to calculate cook yields. In addition, cook times were calculated by recording the time each steak was placed on and removed from the grills. Consumer sensory panel procedures were approved by the Texas A&M Institutional Review Board for the Use of Humans in Research (protocol number STUDY2024-0286). Consumers evaluated sensory steaks for juiciness like/dislike, flavor like/dislike, tenderness like/dislike, and overall like/dislike. For steaks destined for WBSF, three 1.27-cm-diameter cores were taken from each parallel to the muscle fibers using a handheld coring device. Cores were sheared once, perpendicular to the muscle fibers on a United Testing Machine (United SSTM-500; Huntington Beach, CA) at a crosshead speed of 200 mm/min using a 10-kg load cell and a 1.02-cm-thick V-shaped blade with a 60° angle and a half-round peak. Average Newtons required to slice the 3 cores from each steak was calculated. Data were analyzed utilizing JMP Pro (v. 15.2.1; SAS Institute, Cary, NC). The fit model standard least-squares function was used for 1-way analysis of variance, and mean comparisons were conducted using Student’s t test at an α of P value less than 0.05. Microsoft Excel (Microsoft Corporation, Redmond, WA) was used to calculate frequencies for consumer panelists’ demographics.

Results: For overall like/dislike, white-fat cow steaks and Australian steaks had among the highest ratings (P < 0.05), whereas Uruguayan steaks had the lowest (P < 0.05) ratings. USDA Choice steaks ranked higher (P < 0.05) in overall like/dislike than USDA Select steaks, whereas yellow-fat cow steaks did not differ (P > 0.05) from either USDA Choice or USDA Select steaks. White-fat cow steaks, USDA Choice steaks, and Australian steaks had among the highest tenderness like/dislike ratings (P < 0.05). Uruguayan steaks and yellow-fat cow steaks had among the lowest (P < 0.05) tenderness like/dislike ratings. White-fat cow steaks, Australian steaks, and USDA Choice steaks had among the highest (P < 0.05) overall scores for flavor like/dislike, whereas Uruguayan steaks had the lowest (P < 0.05). Flavor like/dislike ratings for USDA Choice and USDA Select steaks did not differ (P > 0.05). Consumers ranked white-fat cow steaks, yellow-fat cow steaks, and Australian steaks highest (P < 0.05) for juiciness liking. In contrast, Uruguayan steaks, USDA Choice steaks, and USDA Select steaks were ranked lowest for juiciness (P < 0.05). Australian and white-fat cow steaks were ranked highest (P < 0.05) overall and received among the highest ratings for tenderness, juiciness, and flavor like/dislike. In contrast, USDA Choice steaks received among the lowest juiciness like/dislike ratings, which likely impacted the overall like/dislike of these steaks. Uruguayan steaks received the lowest or among the lowest ratings for overall like/dislike, tenderness like/dislike, flavor like/dislike, and juiciness like/dislike, with flavor like/dislike being most likely to have the largest impact on overall like/dislike. White-fat cow steaks, yellow-fat cow steaks, and Australian steaks had among the lowest (P < 0.05). USDA Choice steaks, Australian steaks, and yellow-fat cow steaks had similar WBSF values. USDA Select and Uruguayan steaks had among the highest WBSF values.

Conclusion: This study identified potential alternative sources for food service tenderloins that may be more cost effective, without having to sacrifice consumer acceptability. The emphasis consumers place on tenderness resulted in tenderloins from white-fat cow carcasses ranking higher among palatability traits across all 4 factors this study tested for. Consumers also found tenderloins from Australian cattle to have no differences or improved palatability traits when compared with USDA Choice tenderloins. Results from this study indicate white-fat cow and Australian carcasses could both serve as potential sources of tenderloins at lower costs for food service establishments without sacrificing a consumer’s eating experience. Purveyors will be able to use these data to source food service products to meet consumer demands.

Keywords: beef, consumer, tenderness, WBSF, tenderloin.

103 Carcass Weight Prediction Through a Computer Vision System

Nathália F. Souza¹, Gutierrez J. F. Assis², Jenifer M. L. Ramos¹, Cris L. C. Nunes¹, Lilian K. E. S. Jesus¹, Guilherme H. Freitas¹, Ana C. F. S. Souza¹, João RR Dorea³, and Mario L. Chizzotti¹*, ¹UFV, Viçosa, MG, Brazil, ²EPAMIG-ITAP, Pitangui, MG, Brazil, ³University of Wisconsin –Madison, Madison, WI 53706, USA *mariochizzotti@ufv.br

Introduction/Objectives: Accurate prediction of carcass weight is crucial for efficient meat production and processing. Among the various approaches for carcass analysis, image-based methods, leveraging advanced computer vision techniques, offer an alternative technique that enhances accuracy and efficiency. The primary objective of this study was to develop a computer vision system to predict beef carcass weight using shape descriptors extracted from segmented images.

Materials and Methods: A total of 598 RGB images of half beef carcasses, with a resolution of 1280 × 720 pixels, were captured in a slaughterhouse environment along with their respective weights in 2019. These images were preannotated using Roboflow and saved as “.txt” files, then divided into training (70%) and validation (30%) sets. Intersection over union (IoU) and precision were used for model evaluation. Segmentation was performed using the You Only Look Once (YOLO) architecture from the Ultralytics library via transfer learning with the “yolo11-seg.pt” weight. The model was trained on a server at the iDATA of Federal University of Viçosa. After segmentation, shape descriptors, such as area, perimeter, convex hull area (HConvex), solidity, aspect ratio (AR), extent, equivalent diameter (ED), circularity, eccentricity, orientation radians (OR), major axis length (Major), minor axis length (Minor), elongation, CentroidX (CX), and CentroidY (CY), were extracted. These descriptors underwent Pearson correlation analysis to assess relationships between dependent and independent variables using RStudio. Subsequently, the combined dataset (image features and carcass weights) was used to train the least absolute shrinkage and selection operator (LASSO) regression model, which applies L1 penalization. The dataset was further split into training (70%) and validation (30%) sets for LASSO, with performance evaluated using the coefficient of determination (R²) and root mean square error (RMSE).

Results: The YOLO model for beef carcass segmentation (Figure 1) demonstrated exceptional performance, achieving an IoU of 0.96 and a precision of 0.99. These metrics are consistent with previous studies, such as Gonçalves et al. (2020), which reported similar accuracy in beef carcass segmentation while comparing 2 image segmentation methods (Superpixel + CNN and SegNet). The high precision and IoU indicate that the YOLO model effectively captures the targeted carcass regions, offering a reliable approach to automated carcass analysis. Pearson correlation analysis (Figure 2) was performed to assess potential multicollinearity among variables. This analysis revealed strong correlations between several variables, including area and ED (r = 1.00), area and HConvex (r = 0.98), and minor and ED (r = 0.94). These strong correlations suggest redundancy among some variables, highlighting the need for feature selection to improve model interpretability and performance. To address this challenge, the LASSO regression model was employed. LASSO penalizes irrelevant variables and mitigates multicollinearity, allowing for selecting the most informative predictors. The model demonstrated a strong correlation between predicted and actual carcass weights, achieving an R² of 0.7918 and an RMSE of 12.94 kg, which reflects high predictive accuracy. The predictive performance of the model underscores its robustness and reliability in estimating carcass weight from geometric descriptors. The contribution of each variable to carcass weight prediction is depicted in Figure 3. The most influential variables identified were eccentricity (328.770), circularity (226.901), AR (262.500), extent (184.824), and OR (84.593), indicating that shape and orientation characteristics play a pivotal role in estimating carcass weight. Other variables that positively contributed to the model include ED (0.552), major (0.502), minor (0.962), elongation (19.542), and HConvex (0.000096), suggesting that structural features also capture relevant information. On the other hand, some variables exhibited negative coefficients, such as solidity (−11.993), area (−0.002), perimeter (−0.042), and CX (−0.214), indicating a slight inverse relationship with carcass weight. Additionally, CY (0.145) demonstrated minimal impact on the predictive model. These findings indicate that although some geometric descriptors have significant contributions, others may be less relevant to weight prediction. Furthermore, Figure 3 also presents a scatter plot comparing observed and predicted carcass weights. The close alignment of data points along the regression line reflects the model’s robust predictive capacity. This visualization not only demonstrates the accuracy of the LASSO model but also highlights its ability to generalize well to new data.

Conclusion: The YOLO segmentation model effectively segments carcass regions, providing reliable shape descriptors for carcass weight prediction. The LASSO regression model uses these descriptors to predict weight accurately, demonstrating the potential for automating carcass weight estimation in meat processing.

Figure 1.

Carcass Inference Using the Trained YOLO Model.

Figure 2.

Correlation matrix highlighting multicollinear variables. HConvex: Convex Hull Area; AR: Aspect Ratio; ED: Equivalent Diameter; OR: Orientation Radians; Major: Major Axis Length; Minor: Minor Axis Length; CX: CentroidX; CY CentroidY

Figure 3.

Contribution of Variables in the LASSO model and Beef Carcass Weight Prediction. HConvex: Convex Hull Area; AR: Aspect Ratio; ED: Equivalent Diameter; OR: Orientation Radians; Major: Major Axis Length; Minor: Minor Axis Length; CX: CentroidX; CY: CentroidY.

Funding Source: INCT-CA, CNPq, CAPES, FINEP 0248/22, and FAPEMIG RED00172-22, BPD00648-22.

Keywords: YOLO segmentation, shape descriptors.

104 Impact of in Utero Heat Stress on Technological and Processed-Meat Properties of Pork

Dong-Jin Shin¹*, Sung-Su Kim¹, Jin-Kyu Seo¹, Caitlyn Sulliva², Jay S. Johnson², and Yuan H. Brad Kim¹, ¹Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, USA, ²Division of Animal Sciences, University of Missouri, Columbia, MO 65211, USA *shin425@purdue.edu

Introduction/Objectives: Climate change threatens the efficiency and sustainability of pork production, and in utero heat stress (IUHS) has been recognized as particularly detrimental to offspring. This condition arises early in embryonic development when the fetus lacks the ability to dissipate heat, leading to hyperthermia. IUHS is considered to have long-term consequences, potentially compromising piglet growth performance and final meat quality. However, research on the technological and processed-meat properties of pork from IUHS-affected offspring with different genomic heat sensitivities (heat tolerant and heat sensitive) remains limited. Therefore, this study aimed to evaluate the effects of IUHS and heat sensitivities on technological properties of pork emulsions.

Materials and Methods: Pigs were assigned to 4 groups based on the sow’s genomic heat sensitivity and IUHS exposure (n = 9 per group): pigs from heat-tolerant sow under thermoneutral (Tol-TN) or IUHS conditions (Tol-HS) and pigs from heat-sensitive sow under thermoneutral (Sen-TN) or IUHS conditions (Sen-HS). Genomic heat sensitivity of sows was discriminated using single-step genomic best linear unbiased prediction method. Heat stress conditions to the offsprings were defined as thermoneutral (17–22°C) and IUHS (cyclic heat stress, 26°C at night/32°C during the day). From day 60 of gestation until farrowing, all pigs were maintained under thermoneutral conditions. After birth, their offspring were raised in group pens under normal commercial production conditions. At 6 mo of age, barrows were slaughtered at Purdue University Meat Laboratory. At 1 d postmortem, all leg muscles were deboned, ground, and stored frozen until use. The samples were analyzed for quality properties (proximate composition, cooking loss, pH, water holding capacity, instrumental color, and texture profile analysis) and technological properties (protein denaturation, emulsion activity index, and protein solubility). For the pork emulsion application, Tol-TN and Sen-HS meat, which exhibited the most distinct technological properties, were used. In addition, the effects of basic additives (phosphate and salt) were also considered, as they may confound or mask the influence of IUHS. The emulsion was manufactured using different combinations of basal additives, including N (no phosphate/salt), P (phosphate), S (salt), and PS (phosphate + salt). All treatments contained nitrite. The proximate composition, cooking yield, emulsion stability, color, and TPA were analyzed on the emulsion sausages. The effects of heat tolerance and IUHS on raw meat and the effects of selected meat types and additives on sausage were analyzed 2-way. Least-squares means were estimated using the PROC GLIMMIX procedure in SAS 9.4, with Tukey’s test employed for post hoc comparisons (P < 0.05).

Results: The proximate composition of raw meat was influenced by genetic type, wherein Tol generally exhibited higher moisture content and lower protein content than the other treatments (P < 0.05). Myofibrillar and total protein solubility were significantly affected by the interaction between genetic type and IUHS, with Tol-TN showing higher solubility than Sen-HS (P < 0.001). However, no differences were observed in texture profile analysis of ground raw meat (P > 0.05). For the emulsion sausage application, samples from Tol-TN and Sen-HS were selected based on their differences in technological properties. Tol-TN exhibited higher cooking loss than Sen-HS (P < 0.05), regardless of additive effect. Regarding the textural properties of sausages, Tol-TN had lower hardness than Sen-HS, with cohesiveness and chewiness following the same trend (P < 0.05). The emulsion stability was not affected by the animal treatment (P > 0.05). These differences in the quality properties of emulsion sausage could be attributed to the differed protein solubility of raw meat.

Conclusion: The results suggest that the combination of the sow’s heat sensitivity and in utero heat stress adversely influenced the technological properties of pork. Sen-HS exhibited lower moisture contents and protein solubility than Tol-TN. Furthermore, sausages made from Sen-HS exhibited lower cooking yields and greater hardness than those of Tol-TN, indicating poorer emulsification. These findings highlight the potential adverse impacts of in utero heat stress on the technological and processed-meat properties of pork from IUHS-affected offspring, especially when the sow is heat sensitive. Therefore, continued efforts to select heat-tolerant pigs would be a possible strategy to maintain meat quality and technological characteristics.

Funding Source: This project is funded by the Center of Excellence for Bison Studies.

Keywords: IUHS; pork; technological; sausage; processed.

105 Metabolic and Biochemical Factors Influencing the Shelf-Life Stability of Beef Muscles During Postmortem Aging

Lamis Ali*, Mohammad Alruzzi, Chandler Stafford, Sulaiman Matarneh, and Stephan van Vliet, Department of Nutrition, Dietetics and Food Science, Utah State University, Logan, UT 84322, USA *lamis.ali@usu.edu

Introduction/Objectives: Shelf-life stability and meat quality are critical for consumer satisfaction and product sustainability in the beef industry. Postmortem biochemical changes, including pH decline, protein degradation, and oxidative stress, play key roles in determining meat color stability and overall shelf life. These changes are influenced by muscle fiber type and mitochondrial content, which vary across muscles. For example, oxidative muscles, such as psoas major (PM), are more prone to discoloration, whereas glycolytic muscles such as longissimus thoracis (LT) tend to retain color better. Semimembranosus (SM) exhibits intermediate characteristics. Differences in enzyme activity and metabolite abundance likely contribute to these variations, but their specific impact across muscles and aging durations is not fully understood. The objective of this study was to assess the influence of mitochondrial content and metabolic profiles and to identify metabolites associated with the shelf-life stability of different bovine muscles over time.

Materials and Methods: Eight steers of similar genetic background and raised under identical feeding and management conditions were harvested at the Utah State University animal harvest facility using standard commercial procedures and in accordance with US Department of Agriculture inspection. Within 30 min postmortem, the LT, SM, and PM muscles were excised from one side of each carcass, divided into 3 portions, and assigned to aging periods of 0, 7, and 14 d. One portion was snap-frozen in liquid nitrogen (0 d), whereas the remaining portions were vacuum packed and stored at 4°C until the designated aging time point. For pH determination, powdered meat tissue (100 mg) was homogenized in a cold buffer (5 mM iodoacetic acid and 150 mM KCl, pH 7.0) at a 1:8 (w/v) ratio, centrifuged at 17,000 × g for 5 min, and allowed to equilibrate to 25°C before pH was measured using an Orion Star A214 pH meter calibrated with pH 4, 7, and 10 buffer solutions. Color measurements were conducted using a Konica Minolta CR-400 chromameter after blooming the steak surfaces for 20 min at room temperature. CIE L* (lightness), a* (redness), and b* (yellowness) values were collected from 3 random surface locations and averaged. The proportions of oxymyoglobin, deoxymyoglobin, and metmyoglobin (MMb) were determined via the Krzywicki (1979) method using absorbance values at 474, 525, and 572 nm and normalized to A700. For Western blotting, 100 mg of powdered tissue was homogenized at a 1:10 (w/v) ratio in titin solubilization buffer (8 M urea, 2 M thiourea, 3% SDS, 75 mM DTT, 50 mM Tris-HCl, pH 6.8) using a bead-beating homogenizer. After centrifugation at 10,000 × g for 10 min, supernatants were collected, and protein concentrations were determined using the BioRad RCDC protein assay. Proteins of interest— succinate dehydrogenase (SDH; 70 kDa), lactate dehydrogenase (LDH; 35 kDa), glyceraldehyde-3-phosphate dehydrogenase (GAPDH; 37 kDa), and myoglobin (17 kDa)—were quantified via SDS-PAGE and Western blotting. Band intensities were normalized to total protein per lane and then further normalized to a reference sample within each blot.

Results: Although discoloration increased in all muscles as aging progressed, the LT exhibited significantly greater color stability compared with the SM and PM muscles (P < 0.05). LT maintained higher a* values, indicating better redness retention throughout the aging period. Correspondingly, LT had a lower proportion of MMb, the oxidized form of myoglobin associated with discoloration, compared with SM and PM (P < 0.05). Myoglobin content was significantly lower in LT than in SM and PM (P < 0.05), suggesting reduced susceptibility to oxidative discoloration. LT had lower levels of SDH, a mitochondrial enzyme indicative of oxidative metabolism, than SM and PM (P < 0.05). This lower oxidative capacity in LT may contribute to its improved color stability and resistance to oxidative stress during storage. Conversely, LDH, a glycolytic enzyme, was found in higher abundance in LT than in SM and PM (P < 0.05), consistent with its classification as a glycolytic muscle with lower oxidative stress potential. GAPDH, another glycolytic enzyme, showed higher abundance in LT and SM compared with PM (P < 0.05), further supporting the metabolic distinction between these muscles. These enzyme expression patterns support the notion that oxidative muscles, such as PM, which possess higher mitochondrial content and SDH levels, are more prone to lipid oxidation and discoloration, whereas glycolytic muscles, such as LT, exhibit enhanced color stability because of reduced oxidative metabolism and higher LDH activity. SM, having intermediate characteristics, displayed moderate color stability and enzyme profiles between LT and PM. These results indicate that postmortem biochemical traits, such as enzyme activity and myoglobin content, vary significantly by muscle type, contributing to differences in meat quality during aging. The clear association between lower oxidative enzyme abundance and improved color stability suggests that metabolic and mitochondrial characteristics play a critical role in shelf-life stability. Understanding these muscle-specific differences is essential for predicting discoloration trends and improving meat processing strategies to enhance the appearance, freshness, and marketability of beef products.

Conclusion: This study highlights the significant impact of muscle-specific metabolic and enzymatic differences on postmortem beef quality and shelf-life stability. The observed variations in color stability, pH, and protein degradation across LT, SM, and PM muscles were closely linked to their oxidative and glycolytic enzyme activities as well as mitochondrial content. LT, a more glycolytic muscle, demonstrated greater color stability and lower oxidative enzyme abundance, whereas PM, a highly oxidative muscle, was more prone to discoloration and protein degradation during aging. These enzymatic differences, along with mitochondrial content, underscore the biochemical fluctuation underlying muscle-specific postmortem changes in beef. Understanding these mechanisms offers valuable insights into the development of muscle-tailored strategies to improve beef shelf life and quality. However, further research is needed to determine the specific role of individual metabolites and their interactions in regulating postmortem biochemical pathways and influencing beef quality across aging periods.

Funding Source: US Department of Agriculture (USDA) National Institute of Food and Agriculture (NIFA).

Keywords: meat quality, shelf-life stability.

106 How to Use Krzywicki’s Equations on Colorimeter Measurements on Meat Surfaces to More Robustly Quantify Myoglobin Forms?

Daqing (Daching) Piao¹*, Ranjith Ramanathan², Morgan L. Denzer², Morgan Pfeiffer², and Gretchen Mafi², ¹School of Electrical and Computer Engineering, Oklahoma State University, OK 74078, USA, ²Department of Animal and Food Sciences, Oklahoma State University, Stillwater, OK 74078, USA *daqing.piao@okstate.edu

Introduction/Objectives: Meat color is an important sensory attribute that influences purchasing decisions. The perceived color of meat is strongly associated with myoglobin oxygen saturation or, equivalently, the relative proportions of 3 redox forms of myoglobin including oxymyoglobin (Oxy), deoxymyoglobin (Deoxy), and metmyoglobin (Met). There are 2 approaches to quantify the percentage numbers of myoglobin forms on meat surfaces, using commercial handheld devices, such as a colorimeter. The method originated by Krzywicki converts the spectral reflectance at 4 wavelengths (474, 525, 572, and 730 nm but 700 nm in practice) to a spectral reflex attenuance, then uses a set of equations to compute the percentage numbers of Met and Deoxy. Krzywicki’s equations do not require creating myolobin form standards. However, Krzywicki’s equations can produce unrealistic numbers of myoglobin forms. The objective of this research is to develop an in-depth understanding of Krzywicki’s equations and test whether a modified approach enables more robust practical uses.

Materials and Methods: Vacuum-packaged US Department of Agriculture (USDA) Choice loins were transported on ice to the University’s Robert Kerr Food and Agricultural Products Center. Approximately 6 d postmortem, muscles were sliced into 2.54-cm-thick steaks and packaged immediately after cutting in white Styrofoam trays overwrapped with polystyrene polyvinyl chloride film (15,500–16,275 cm³ O₂/m²/24 h at 23°C). All steaks were placed in a coffin-style retail display case for 7 d at 2°C ± 1°C. The average lighting in the different areas of display case ranged from 1,612 to 2,152 lux throughout retail display. A total of 44 USDA Choice loins were procured at 3 different times (14 psoas major [PM], 22 longissimus lumborum [LL], and 8 semitendinosus [ST]). The steaks from each loin were placed on Styrofoam trays wrapped with a polyvinyl chloride film. Surface color was measured daily using a handheld spectrophotometer. The number of days of retail display was 6 or 7. The measurements from 7 steaks of LL muscles over a retail display of 6 d were used for sub-aim 1 testing a baseline configuration, and the entire set of 44 steaks was used for sub-aim 2 testing a modified approach of utilizing Krzywicki’s equation. Raw color analysis daily instrumental color was measured using a HunterLab 4500L MiniScan EZ Spectrophotometer (2.5-cm aperture, illuminant A, and 10° standard observer angle). The surface of each steak was read at 3, 5, or 6 randomly selected positions, and the surface color was characterized by the Commission Internationale de l´Eclairage (CIE) L*, a*, and b* values and reflectance over 400 to 700 nm. Chroma was determined using CIE a* and b* values. The experimental design was a randomized complete block. Loin from each animal was served as a block. Main treatment effect was time. Previous studies reported that LL, PM, and ST muscles have differences in color stability. Hence, data were analyzed separately for muscle type. For each variable [Oxy]%, [Deoxy]%, and [Met]%, mean and standard deviation (STD) were calculated. The progression of [Met]% among PM, LL, and ST muscles with time was compared and considered significant at P value less than 0.05.

Results: Direct estimation of [Oxy]%, [Deoxy]%, and [Met]% of the 7 LL steaks over the retail display were compared using the original and a modified approach of Krywicki’s equation. Testing on colorimeter measurements indicated that Krzywicki’s equation for directly estimating [Oxy]% is sensitive to the baseline reference projected for 730 nm. The modified Krzywicki’s equations performed better, with or without including 730 nm, in specifically resolving a more realistic increase of the [Met]% during the retail display. The 2 algorithms (original and modified) have been applied for estimating [Met]% of the total 44 muscles of 3 types. The results are presented in Figure 1. The left panel summarizes the most relevant equations of each of the 2 algorithms of implementing Krzywicki’s equations. The right panel compares the [Met]% estimated by 2 algorithms of implementing Krzywicki’s equations against chroma over the duration of display. Within the right panel, the top figure corresponds to 14 PM muscles combining 2 groups, the middle figure corresponds to 22 LL muscles combining 3 groups, and the bottom figure corresponds to 8 ST muscles of 1 group. Within each figure of a specific muscle type, the trace marked by black empty diamonds corresponds to applying the original algorithm, and the trace marked by purple solid circles corresponds to applying the modified algorithm. Of the 8 ST muscles, both the chroma and [Met]% remain relatively stable over the duration (7 d) of retail display. Of the 22 LT muscles, the chroma reduced steadily, and [Met]% increased steadily over the durations (5 or 6 d) of retail display. Of the 14 PM muscles, the chroma reduced steadily over the durations (5 or 6 d) of retail display, and [Met]% increased grossly over the duration of display, but it had a pronounced change appearing as a sudden increase (jump) of [Met]% as the chroma reduced to slightly below 30.

Conclusion: This study revisited Krzywicki’s individual equations of [Oxy]%, [Deoxy]%, and [Met]% based on tissue optics. The original and a modified approach to Krzywicki’s equations were tested on 44 loins (LL, n = 22; PM, n = 14; ST, n = 8). Testing on colorimeter measurements indicated that Krzywicki’s equation for directly estimating [Oxy]% could be sensitive to the baseline reference projected for 730 nm. The modified Krzywicki’s equations performed better, with or without including 730 nm, in specifically resolving a more realistic increase of the [Met]% during the retail display. The modified algorithm applied to PM muscles revealed a pronounced rapid increase of the [Met]% as the chroma reduced to approximately 30, compared with a steady increase of the [Met]% in LL muscles at similar numbers of chroma. The results suggest that modified Krzywicki’s equations provide a more realistic estimation of the percentage numbers of myoglobin forms on steak surfaces than original equations.

Figure 1.

Referenced in text above

Funding Source: US Department of Agriculture National Institute of Food and Agriculture (100005825) (2022-67017-36538) grant program.

Keywords: myoglobin, discoloration, Krzywicki’s equations, colorimeter.

107 Exploring the Effects of Increasing Weight at Slaughter on Belly Quality Attributes of Gilts and Barrows

Manuel Juárez¹*, Justice B. Dorleku¹, Benjamin M. Bohrer², Philip O. Soladoye¹, and Tawanda Tayengwa¹, ¹Agriculture and Agri-Food Canada (AAFC), Lacombe, Alberta, Canada, ²Department of Animal Sciences, The Ohio State University, Columbus, OH 43210, USA *manuel.juarez@agr.gc.ca

Introduction/Objectives: The slaughter weight of commercial pigs in North America has been consistently increasing over time, from 110 to 115 kg in 2010 to the current weight of approximately 130 kg. Increasing carcass weight is known to have significant impacts on pork quality traits linked to, among other factors, changes in the chilling rate, and these effects are often different in gilts and barrows. However, few studies have explored the impact of increasing slaughter weight on pork belly quality. Pork bellies constitute nearly 20% of the total carcass value (Mandigo, 2000 <https://eposterboards.submittable.com/submit/307982/amsa-rmc-abstract-submission-portal#_ENREF_22>), with certain buyers willing to pay premiums for primal cuts that meet specific quality standards. Packers prefer bellies that are fairly thick and firm, as these characteristics lead to higher processing yields and increased profitability (Person et al., 2005 <https://eposterboards.submittable.com/submit/307982/amsa-rmc-abstract-submission-portal#_ENREF_31>). This study aimed to evaluate the impact of increased slaughter weight on a comprehensive set of quality attributes of bellies from gilts and barrows.

Materials and Methods: All experimental procedures were approved by the Agriculture and Agri-Food Canada Lacombe Research and Development Centre’s (AAFC-LRDC, AB, Canada) Animal Care Committee. Pigs were cared for following commercial practices, as outlined under the guidelines established by the Canadian Council on Animal Care (2009). A total of 2,110 commercially pigs, including 1,055 barrows and 1,055 gilts (Large White × Landrace sows × Duroc boars; Genesus Genetic Technology, MB, Canada), were slaughtered at 2 different slaughter weights (light: 114.7 ± 0.16 kg; heavy: 128.3 ± 0.14 kg) at the AAFC-LRDC federally inspected abattoir over 75 different slaughter dates. After slaughter, lean meat yield was measured between the third- and fourth-last ribs using a grading probe (Anitech PG100, Anitech Information Systems Inc., Markham, ON, Canada). Carcasses were then separated into primal cuts following the International Meat Purchase Specifications (IMPS) for pork (IMPS, 2014). Individual primal cuts were scanned using dual energy x-ray absorptiometry to measure lean and fat content (Soladoye et al., 2016). Total carcass lean and fat were calculated as the sum of fat tissues from all individual primal cuts. A pork chop from the center of the loin was used to measure intramuscular fat content using the Smart Trac Fat Analyzer Model 907,955 (CEM Corporation, Matthews, NC). A 5-g sample of backfat from the shoulder was sampled from each carcass and stored at −80°C until further fatty acid analyses following the protocol described previously (Turner et al., 2014), and iodine value was then calculated (AOCS, 1998). Belly weight percentage, length, and width as well as side lean, side fat, intermuscular fat (side seam), subcutaneous fat (side subcutaneous), and side thicknesses were measured following previously published protocols (Soladoye et al., 2017). Individual bellies were also tested using the Belly Bender V2, which provides an objective measurement (°) of belly firmness (Uttaro et al., 2024). Data were analyzed using the Mixed Model algorithm of the SAS Institute, Inc. (v9.4; SAS Inst. Inc.), incorporating weight, sex, and their interaction as fixed factors, with kill date as a random effect. When the model indicated significance (P < 0.05), group means were determined using the LSMEANS statement.

Results: For most carcass traits except lean meat yield percentage, significant interactive effects (P < 0.05) were observed between weight and sex. Total carcass fat percentage was highest in heavy males (34.2%) and lowest in light females (29.6%). Intramuscular fat content was highest in both light and heavy males (4.10%) and lowest in light females (3.55%). Lean meat yield percentage was consistently higher (P < 0.001) in light pigs (59.7%) compared with heavy pigs (50.2%) and in females (60.0%) compared with males (58.8%). Regarding belly characteristics, males (18.7%) and heavy pigs (18.8%) had higher (P < 0.05) belly weight percentage than females (18.6%) and light pigs (18.5%). Bellies from heavy male pigs had the highest fat content (34.8%, P = 0.016), whereas light female pigs had the lowest (31.2%). Belly length and width were greatest in heavy (69.8 cm and 25.4 cm, respectively) and female pigs (68.2 cm and 25.4 cm, respectively) (P < 0.05). Side lean thickness was lowest in light males (2.13 cm, P = 0.033). Side fat, seam, subcutaneous, and total thickness were consistently higher in heavy (2.77 cm, 4.03 cm, 2.34 cm, and 1.45 cm, respectively) and male pigs (2.74 cm, 4.10 cm, 2.41 cm, and 1.46 cm, respectively) (P < 0.001). The same trend was observed for the belly bend angle, with higher values in heavy (149.3°) and male pigs (148°) (P < 0.001).

Conclusion: As expected, increasing the slaughter weight in commercial pigs affected carcass composition and lean meat yield. The interactive effects between slaughter weight and sex, which were not observed in the traditional grading probe evaluations, should be considered as animals continue to get heavier. Similarly, total belly fat content was influenced by the interaction between weight and sex, with differences between gilts and barrows becoming smaller in heavier pigs. Conversely, belly dimensional traits, firmness, and iodine value were not affected by this interaction; fat layers became thicker and firmer as both males and females grew heavier. This trend needs to be monitored, as excess belly fat, although beneficial for firmness, is not desirable for premium buyers. Future research should explore the impact of heavier slaughter weights (140–150 kg) and their interaction with other novel production factors, such as immunocastration.

Funding Source: The authors would like to acknowledge funding from Swine Innovation Porc (Project #1787 “Classifying Canadian pork based on quality attributes”).

Keywords: pork, belly, weight, sex, firmness.

108 Muscle Fiber Type Differences Between Conventional Beef, Beef × Dairy, and Holstein Steers

James Brister*, Jacob, McMillan, Luke Fuemiss, Dale Woerner, Brad Johnson, Blake Forarker, Meat Science & Muscle Biology, Texas Tech University, Lubbock, TX 79409, USA *jmbrister@outlook.com

Introduction/Objectives: Certain meat qualities, such as tenderness, color, and water holding capacity, are linked to proportions of muscle fiber types, wherein type I and IIA correlate with higher-quality meat and IIX with poorer quality. In a previous study, subprimal yield percentage was greater in conventional beef cattle and high-yielding (HY) beef × dairy cattle than low-yielding (LY) beef × dairy cattle and dairy cattle. The objective of this study was to compare muscle fiber type characteristics between conventional beef steers, HY and LY beef × dairy steers, and Holstein steers and relate these muscle characteristics to traditional measures of muscularity, such as ribeye area and subprimal yield percentage.

Materials and Methods: To obtain muscle tissue samples, conventional beef steers, beef × dairy steers, and Holstein steers were harvested and selected for fabrication based on industry average hot carcass weight and fat thickness for their respective cattle type. Beef × dairy steers were subdivided into HY and LY groups after fabrication. To collect data on the myosin heavy chains (MHC) for the classes of steers, frozen samples of the longissimus dorsi were cut perpendicular to the muscle fibers to produce sections, which were fixed onto glass slides. The slides were then prepared with immunohistochemical staining and artificially colored and analyzed using NIS-Elements Imaging software. Low-quality images were culled from the image bank, and MHC types I, IIA, and IIX of each sample were counted, and cross-sectional area was measured. The mean cross-sectional area (CSA) and mean CSA proportional to MHC count of each fiber type were calculated for each sample. Mean CSA of MHC, proportional count of MHC, and proportional CSA were compared between cattle type (n = 11–14 carcasses per cattle type). A Pearson correlation was conducted between mean CSA of each MHC type and both subprimal yield percentage and ribeye area.

Results: Mean CSA of MHC-I was not different between cattle types (P = 0.134). Mean CSA of both MHC-IIA and MHC-IIX was greatest (P < 0.05) in HY beef × dairy, intermediate (P < 0.05) in Holstein, and least (P < 0.05) in LY beef × dairy and conventional beef. Comparing the proportional counts of all 3 MHC types showed no differences between classes (MHC-I, P = 0.142; MHC-IIA, P = 0.152; MHC-IIX, P = 0.202). Analysis of mean CSA proportional to MHC count of MHC-I showed no differences between classes (P = 0.230), whereas the same analysis of MHC-IIA was the greatest (P < 0.05) in beef × dairy HY, intermediate (P < 0.05) in both beef × dairy LY and Holstein, and least (P < 0.05) in conventional beef. MHC-IIX was greatest (P < 0.05) in conventional beef, intermediate (P < 0.05) in both beef × dairy LY and Holstein, and least (P < 0.05) in beef × dairy HY. The Pearson correlation of both MHC-I and MHC-IIX mean CSA showed no correlation to ribeye area (MHC-1: P = 0.740, r = 0.047; MHC-IIX: P = 0.079, r = 0.243), whereas the Pearson correlation of MHC-IIA showed positive correlation to ribeye area (P < 0.05, r = 0.335). The Pearson correlation of mean CSA of all MHC types showed no correlation to subprimal yield percentage (MHC-I: P = 0.219, r = 0.171; MHC-IIA: P = 0.089, r = 0.236; MHC-IIX: P = 0.212, r = 0.174).

Conclusion: Mean CSA proportional to MHC count for MHC-IIA fibers wherein beef × dairy HY is greater than the other 3 classes demonstrated a positive quality obtained through crossbreeding that is not present in solely conventional beef or dairy steers. The data involving mean CSA proportional to MHC count for MHC-IIX in which conventional beef is greater than the other 3 classes demonstrates that there is potential for genetic selection to decrease the higher proportional mean CSA of type IIX fibers in conventional beef while increasing the proportional mean CSA of type IIA fibers, possibly by the inclusion of dairy genetics. The correlation between mean CSA of MHC-IIA and ribeye area shows that larger MHC-IIA fibers can influence specific muscularity measures and increase ribeye area, with an opportunity for further research on effects of CSA of MHC-IIA on different muscularity measures.

Funding Source: Cargill Protein.

Keywords: fiber type, yield, beef-on-dairy.

109 Investigation of Composition, pH, Tenderness, Cook Loss, and Volatile Compounds of M. Longissimus Lumborum Steaks From Beef Carcasses of 4 Color Categories

Thomas W. Dobbins¹*, Manuel S. Hernandez¹, Bradley J. Johnson¹, Dale R. Woerner¹, Jerrad F. Legako¹, Nicholas C. Hardcastle², and Ranjith Ramanathan³, ¹Department of Animal and Food Sciences, Texas Tech University, Lubbock, TX 79409, USA, ²Cargill Protein, Wichita, KS 67202, USA, ³Department of Animal and Food Sciences, Oklahoma State University, Stillwater, OK 74075 USA *tdobbins@ttu.edu

Introduction/Objectives: Meat color is one of the primary decision tools consumers use when purchasing beef. Variation in color leads to large economic losses each year, especially related to dark cutting beef, which is generally associated with a dark red or purple color and increased pH. The most recent beef quality audit reported that 1.8% of cattle in the United States are identified as dark cutting, and these cattle lead to an approximate $288 million economic loss. Furthermore, changes in pH can also lead to differences in tenderness, water holding capacity, and flavor development. Thus, variation in the color of beef carcasses can alter palatability and consumer perception through direct and indirect mechanisms. The objective of this study was to evaluate the composition, tenderness, cook loss, and volatile compound profile of M. longissimus lumborum beef steaks from 4 carcass color categories.

Materials and Methods: Carcasses were collected across 9 consecutive months from 2 commercial abattoirs. A E+V grading camera was used to evaluate carcass color, backfat thickness, and marbling score. Carcasses were categorized according to the lowest color score from the grading camera and placed accordingly: dark (DARK; L* ≤ 55), intermediate (INT; 55 < L* ≤ 59), normal (NORM; 60 ≤ L* <80), or light (LIGHT; L* ≤ 80). At each collection, 6 carcasses per color category were collected for a total of 215 carcasses across the entire study (DARK = 53; INT = 54; NORM = 54; LIGHT = 54). A 5.08-cm portion was removed from each side, transported to Texas Tech University, aged until 5 d postmortem to be snap-frozen and homogenized or 14 d postmortem and frozen as a steak at −20°C until further analysis. Powder homogenate from the 5-d samples was utilized for determination of pH by creating a slurry with water, and the pH was determined using a benchtop pH meter. Steaks aged 14 d were utilized for proximate analysis, slice shear force (SSF), and volatile compound analyses. Samples were coarse ground and fine ground through a tabletop grinder prior to proximate analysis. Percentage of moisture, fat, protein, and collagen was measured using near infrared spectroscopy. Another steak aged to 14 d postmortem from each carcass was weighed then cooked on a flat-top grill at a surface temperature of 163°C to a target internal temperature of 71°C. Following cooking, the steak was weighed again, and a 1 × 5–cm slice was removed from the lateral end. The removed slice was sheared perpendicular to the muscle fiber orientation using an SSF machine. The remaining components of the cooked steak were snap-frozen in liquid nitrogen and homogenized. Cook loss was calculated as the percentage change in initial and final weight after cooking. The cooked homogenate was utilized for volatile compound analysis wherein volatile compounds were extracted through headspace-solid phase microextraction and analyzed using gas chromatography–mass spectrometry. All data were analyzed using a generalized mixed linear model with significance declared at P value less than or equal to 0.05 and tendencies at P value less than or equal to 0.10, with a main effect of color category. Peak cook temperature, percentage fat, and marbling score were considered as covariates and included in the model if P value was less than or equal to 0.10.

Results: Camera color scores were greatest (P < 0.05) in LIGHT carcasses and least (P < 0.05) in DARK carcasses; NORM carcasses were greater (P < 0.05) than INT and DARK, whereas INT was greater (P < 0.05) than DARK. Backfat thickness was increased (P < 0.05) in LIGHT carcasses compared with INT and DARK, whereas NORM carcasses had greater (P < 0.05) backfat than INT. Marbling scores were greater (P < 0.05) in LIGHT carcasses compared with NORM and INT, whereas DARK carcasses had increased (P < 0.05) marbling scores compared with INT. Muscle pH was greatest (P < 0.05) in DARK (6.44) carcasses, and INT (5.84) carcasses had an increased (P < 0.05) pH compared with NORM (5.55) and LIGHT (5.43). SSF values were increased (P < 0.05) in INT (17.54 kg) carcasses compared with all other color categories (DARK = 14.93 kg; NORM = 14.80 kg; LIGHT = 14.63 kg). Cook loss was least (P < 0.05) in DARK (13.19%) carcasses, whereas INT (16.99%) carcasses had less (P < 0.05) cook loss compared with LIGHT (18.97%) carcasses. Fat percentage was greatest (P < 0.05) in LIGHT (5.75%) carcasses, whereas NORM (3.89%) carcasses had an increased (P < 0.05) fat percentage compared with INT (2.60%). Moisture content was greatest (P < 0.05) in INT carcasses (72.28%). DARK (71.77%) and NORM (71.02%) carcasses had increased (P < 0.05) moisture content compared with LIGHT (70.15%) carcasses. Protein content was increased (P < 0.05) in NORM (24.50%) carcasses compared with DARK (23.96%) and LIGHT (23.77%) carcasses. Additionally, protein content was greater (P < 0.05) in INT (24.26%) carcasses compared with LIGHT (23.77%). There were no differences (P > 0.05) in the percentage of collagen between carcass color categories. Varied impact was observed for 61 targeted volatile compounds. Twenty-five compounds differed (P < 0.05) between color categories, and an additional 5 compounds tended to differ (P < 0.10) between categories. Furans, ketones, oxalones, pyrazines, pyrroles, Strecker aldehydes, sulfides, and thiopenes associated the Maillard reaction were reduced (P < 0.05) in DARK carcasses. There were no differences (P > 0.05) between color categories in alcohols or terpenes within lipid degradation pathways. There tended (P < 0.10) to be variation in the abundance of esters in lipid degradation pathways across color categories. Aldehydes, carboxylic acids, hydrocarbons, and ketones associated with lipid degradation pathways were reduced (P < 0.05) in DARK carcasses.

Conclusion: The color associated with beef is strongly related to the ultimate pH of the muscle. Furthermore, the interaction of pH and color also contributes to variation in both tenderness and water holding capacity of these steaks. Both DARK and INT carcasses produce steaks of less desirable color; however, INT carcasses produce tougher steaks. Through increases in pH and subsequent increases in water holding capacity, the production of volatile flavor compounds associated with the Maillard reaction are reduced during the cooking process. This study concludes that variation in color attributed to differences in pH and other factors not only influence the formation of an undesirable darker color but also reduce volatile compounds associated with a positive eating experience. Finally, the differences between NORM and LIGHT beef are almost exclusively related to the composition of the meat.

Funding Source: Research coordinated by the National Cattlemen’s Beef Association, a contractor to the Beef Checkoff.

Keywords: beef, dark cutters, meat quality.

110 Improved Ground Beef Shelf-Life Estimation Using a Spoilage Gas Sensor for Water-Soluble Volatile Compounds and Predictive Modeling

Jimena Rodriguez^1,*, Sabrina Blandon¹, Giandrin Barandun², Max Grell², and Jerrad F. Legako¹, ¹Texas Tech University, Lubbock, TX 79409, USA, ²Blakbear Ltd, London, UK *jimerodr@ttu.edu

Introduction/Objectives: Ground beef is commonly prepared in polyvinyl chloride (PVC) overwrap packaging for purchase at retail. The shelf life of ground beef is a key quality concern for processors, retailers, and consumers. However, existing methods for assessing shelf life are slow, labor intensive, and unable to account for variation between individual packages. Current “use-by” or “best-by” dates are not entirely applicable, given that they are not reflective of individual package shelf life. In this study, we evaluate the use of a spoilage gas sensor for water-soluble volatile compounds as a rapid, nondestructive tool for shelf-life estimation of ground beef. By correlating sensor responses with standard spoilage indicators, we demonstrate its potential for real-time prediction and improved assessment of package-to-package shelf-life variability.

Materials and Methods: Five 4.5-kg, 85% lean ground beef chubs were obtained from a local purveyor and transported to Texas Tech University. Approximately 0.28 kg of ground beef was weighed, formed into a brick and placed onto a black polystyrene tray with an absorbent pad and spoilage gas sensor and then overwrapped with oxygen-permeable PVC film (n = 51). Packages were randomly assigned to a display period—0 to 7 d—and immediately placed into a multideck-style retail case under continuous fluorescent lighting. Each day, samples were removed from the retail case and measured for surface color, lipid oxidation, and microbial quantification. Sensor data were collected continuously from individual sensors through a BLE5.0 gateway and subsequently uploaded to a cloud server for further processing. Resulting sensor data were retained as daily sensor response adjusted for temperature. Using a previously developed predictive model, the sensor data were analyzed to estimate aerobic counts (AC) in ground beef, generating a predicted AC value (CFU/g) for each sensor on each sampling day. Surface color was recorded daily using a Hunter MiniScan EZ colorimeter. Collected CIE L*, a*, b* values were utilized to measure surface color and used to calculate chroma and hue angle. Concentrations of malondialdehyde were measured daily using the 2-thiobarbituric acid reactive substances (TBARS) assay following the method modified by Luque et al. (2011). Lastly, AC and lactic acid bacteria (LAB) were measured daily over the 7-d display period through the use of TEMPO. All data were transformed into log 10 CFU/g for statistical analyses. Meat quality data were analyzed using the GLIMMIX procedure of SAS version 9.4, wherein day served as fixed effect, and package was the experimental unit. Quality and sensor data were averaged to obtain a singular numerical value for assigned display period and used for statistical analysis. Meat quality, raw sensor, and sensor model (AC) data were used to run a linear regression using R, wherein lab-collected data was set as a dependent variable and sensor and model data as an independent variable.

Results: The following parameters showed significant changes over the display period (P < 0.001): Color quality and stability decreased, with day 0 samples exhibiting the highest a* (redness) values that declined over time. Similarly, chroma and hue values decreased throughout the display period. Lipid oxidation increased with longer display times. Both aerobic and lactic acid bacterial concentrations were higher with increased display duration. Linear regression was conducted to examine the relationship between average meat quality data, raw sensor output, and AC model output. Average a* (redness) values reported an adjusted R² of 0.52 for raw sensor data and 0.77 for model output data. Chroma (intensity) was found to have an R² of 0.56 for raw sensor data and 0.79 for model output data. The lipid oxidation relationship had an adjusted R² value of 0.61 for the raw sensor data and 0.79 for the model output data. Aerobic bacterial count had an R² of 0.77 for raw sensor data and 0.93 for the model output data. LAB had an R² of 0.46 for raw sensor data and 0.67 for the model output data.

Conclusion: Deterioration of ground beef samples was evident over the 7-d simulated retail display. Positive correlations were observed between meat quality parameters, raw sensor output, and data from the predictive model. The model, designed to predict aerobic colony counts, performed best in this task (R² = 0.93). Compared with direct sensor output, the model improved prediction accuracy by more than 0.23 R² on average for color degradation and lipid oxidation. Raw sensor values show a nonlinear but monotonic relationship with lipid oxidation data, suggesting that a model can be trained to more accurately predict TBARS measurements. A similar trend was observed for color degradation, although the latter may present cyclical patterns that require more advanced modeling approaches. These findings support the feasibility of rapid, real-time shelf-life prediction with high predictive accuracy for aerobic counts. Future work may further augment models to increase accuracy of other key meat quality attributes.

Funding Source: Funded in part by Blakbear.

Keywords: real-time measurement, meat quality, packaging.

111 Location and Cutting Style Influence Beef Bottom Round (Biceps Femoris) Steak Tenderness and Display Color Attributes

J. Anna Scott^*, Clint T. Lee, Dewey Hamp Thomas, and Alexander M. Stelzleni, University of Georgia, Athens, GA 30602, USA *jameson.scott@uga.edu

Introduction/Objectives: The biceps femoris (bottom round) was previously identified as a possible value-added cut from the beef round to maximize profitability from each carcass; however, greater merchandizing has not been adapted because of its varying fiber orientation, color and color stability, and inconsistent tenderness. Common fabrication practices for the bottom round are to cut into steaks and roasts in a proximal to distal orientation with little attention to muscle fiber direction or location within the subprimal, leading to increased variation. Research has shown that when steak fabrication is reoriented perpendicular to fiber orientation, tenderness is improved, as opposed to inevitably being parallel to fiber orientation with traditional fabrication in areas of the bottom round. The objective of this study was to evaluate an economical change in cutting methods of the beef bottom round to understand which locations are best suited to increase steak yields and maximize tenderness and color shelf life.

Materials and Methods: Sixty paired Institutional Meat Purchase Specifications (IMPS) #171B beef bottom rounds were selected 3 d postmortem. Fifteen carcasses from US Department of Agriculture Prime (PR) and Low Choice (LC) were utilized. Bottom rounds were vacuum sealed and transported (164 km) to the University of Georgia Meat Science and Technology Center for continued aging (0 ± 2°C). Fourteen days postmortem, bottom rounds were fabricated by removing the ischiatic head and separated into 3 sections (dorsal [S1], medial [S2], distal [S3]) perpendicular to the long-axis based on predominant fiber orientation. Right side (RS) bottom rounds were fabricated into 2.54-cm steaks perpendicular to the muscle’s long-axis simulating traditional fabrication. Left side (LS) bottom rounds were fabricated into 2.54-cm steaks perpendicular to each section’s predominant fiber orientation. Steaks were randomly assigned to either Warner-Bratzler shear force (WBSF) or retail display. Steaks designated for WBSF were vacuum sealed and frozen (−20°C) for subsequent analysis. Steaks designated for retail display were placed onto Styrofoam 2S trays, overwrapped with polyvinyl chloride film, and placed in Hussman open-top coffin cases (2 ± 2°C) under continuous light (lux » 1,781). Steaks for WBSF analysis were thawed (2 ± 2°C) 24 h and cooked on clam-shell grills (63°C) targeting medium-rare degree of doneness. Following cooking, steaks were cooled overnight (2 ± 2°C). Six cores (1.27-cm diameter) were removed parallel to fiber orientation and sheared (crosshead speed: 250 mm/min; load cell of 500 N). The peak force was recorded and averaged. During 5-d simulated retail display, CIE L*, a*, and b* and spectral measurements were recorded daily (Hunter LAB MiniScan, Illuminant A 10°), with 3 scans taken per sample and averaged. Hue angle, chroma, and Delta E were calculated. Data were analyzed as a split-split-plot utilizing Proc MIXED (SAS Inst., V9.4). Carcass was considered the whole plot, biceps femoris from the respective side was the sub-plot, and section within biceps femoris was the sub-sub-plot. Fixed effects included quality grade (QG), fabrication, section location, and day. Steak within location was the random term. Means were separated using the PDIFF option in LSMEANS with Tukey’s adjustment at α less than or equal to 0.05.

Results: Steaks fabricated traditionally lost more moisture thawing than steaks alternatively fabricated (P < 0.01). No other differences were observed for percentage thaw loss (P > 0.30). There was a fabrication × QG interaction for percentage cook loss (P = 0.05), wherein RS-LC steaks exhibited greater cook loss than LS-LC (P = 0.03). There was a fabrication × section interaction (P = 0.05) for WBSF, wherein RS-S2 steaks were less tender (P < 0.01) than all other steaks. Overall, steaks fabricated traditionally and from S2 were less tender (P < 0.01). Steaks from S1 and S3 exhibited similar WBSF (P = 0.50). As retail display days increased, color quality decreased. To highlight the fabrication, section, and QG effects, data were analyzed by day. There were no 2-way or 3-way interactions for L* or a* (P > 0.09). Prime steaks had greater L* (P ≤ 0.03; all days) and a* (P ≤ 0.01; days 1, 2, 3, 4, 5) than LC. On all days, S2 steaks were lighter (P < 0.05) compared with S1 and S3, which were similar (P > 0.05) on days 0, 1, and 3; however, on days 2, 4, and 5, S3 steaks were lighter (P < 0.05) than S1. Section effects for a* were different on days 1, 2, and 5 (P < 0.04). On days 1 and 2, S3 steaks were less red (P < 0.05) than S1, and on day 5, S2 was redder than S3 (P < 0.05). On days 1 and 2, RS steaks were lighter (P < 0.05) compared with LS steaks. Steaks from RS had greater (P < 0.05) a* on days 1, 2, 3, and 4 compared with LS. There was a fabrication effect for chroma on days 1, 2, and 3, wherein RS steaks were more saturated (P < 0.05) than LS. There was a QG effect on days 1, 2, 3, 4, and 5, as PR steaks were greater (P < 0.05) than LC. There was a section effect on days 1 and 2, wherein S1 steaks were greater (P < 0.05) than S3. On day 5, S2 steaks were greater (P > 0.05) than S3. For hue, LS steaks were greater (P < 0.05) on all days compared with RS. On days 0 and 1, S1 steaks had a lower hue value (P < 0.05) compared with S2 and S3. On day 2, S2 was greater (P < 0.05) than S1 but was similar (P > 0.05) to S3. For DE, there was a fabrication effect on days 1, 2, 3, and 4, as LS steaks had greater (P < 0.05) change compared with RS. There was a QG effect for all days, as LC steaks had greater (P < 0.05) change than PR. On day 5, there was a section effect, as S3 had greater (P < 0.05) change compared with S2.

Conclusion: Changes in fabrication techniques based on muscle fiber orientation and location within the bottom round showed improvements in tenderness. Although all samples would be considered tender according to WBSF, the differences are such that a consumer may still be able to detect difference. Therefore, these preliminary data suggest the dorsal and distal sections could be used as a value-added steak product; however, the medial section would still be best utilized as a roast product. A similar section trend follows for color evaluations, as the medial section was initially lighter and less red in color and had the greatest change over time, suggesting it would be least suitable for retail display. Further work needs to be done to characterize fiber type differences within the biceps femoris and trained taste panels to possibly further investigate differences in fabrication methods.

Funding Source: Georgia Commodity Commission for Beef (GACCB).

Keywords: tenderness, color, biceps femoris.

112 Shelf-Life and Color Stability of Deli-Style Ham and Turkey Slices Treated With Far Ultraviolet-C Light

Jonathan J. McDonald*, Hui Zhang, Jenny Park, Yi-Cheng Wang, and Bailey Harsh, University of Illinois, Urbana-Champaign, IL 61820, USA *jm93@illinois.edu

Introduction/Objectives: Ultraviolet light, specifically the 254-nm wavelength classified as ultraviolet-C (UVC; 200–280 nm), has been approved by the US Food and Drug Administration for surface microorganism control since the late 2000s, although it can pose a health risk to humans. Far-UVC (200–230 nm) is a safer wavelength range while remaining effective at microorganism control and may be an alternative to higher-wavelength UVC. Domestically, ready-to-eat deli meat sales have doubled in the past decade, with $48.6 billion of sales in 2024. With deli meat demand growing, food safety interventions are needed to reduce the risk of foodborne illness outbreaks. Prior research has reported 222-nm far-UVC had a 1-log reduction of salmonella and listeria in deli turkey meat. However, far-UVC effects on meat quality were not investigated. Therefore, the objective of the current study was to evaluate the impact of far-UVC treatment on deli turkey and ham visual quality over a 5-d period.

Materials and Methods: Commercially available presliced deli turkey quarter-loaves (N = 20) and deli ham loaves (N = 20), with 2 brands used for each protein source, were purchased. For each deli turkey quarter-loaf, the light-exposed face was discarded, then 3 consecutive 1.2- to 1.5-cm-thick slices were used for retail display. For deli turkey, 3 treatments were used: no far-UVC light (CON), 222-nm far-UVC light treated for 3 min to a dose of 337 mJ/cm² (L-UVC), and 222-nm far-UVC light treated for 7 min to a dose of 786.3 mJ/cm² (H-UVC). For deli ham loaves, loaves were sliced until diameter was consistent, and slices were selected similar to turkey. Only 2 treatments were applied to deli ham: CON and H-UVC. Retail display slices were placed in 25.4 × 20.4–cm 1.25-mm-thick Reloc Slider Deli Bags (FantaPak Co., Livonia, MI), assigned a random 3-digit number, and placed in a 3°C upright retail style display cooler under LED lights (4000K, ElectraLED, Inc., Clearwater, FL) for 5 d. Turkey and ham trials occurred separately with turkey packages left in the cooler for the entire 5 d, whereas hams remained in dark storage, preventing rapid surface discoloration, except for an hour daily for evaluation. Instrumental color (CIE L*, a*, and b*) and spectral data were collected with a HunterLab Miniscan EZ (Hunter Associates Laboratory Inc., Reston, VA) equipped with illuminant D65, 10° standard observer angle, a view area of 31.8 mm, and was calibrated with a black and white tiles. Six panelists evaluated samples on a 7-point hedonic scale (1 = very definitely would not purchase, 2 = definitely would not purchase, 3 = probably would not purchase, 4 = may or may not purchase, 5 = probably would purchase, 6 = definitely would purchase, 7 = very definitely would purchase). Visual likelihood of purchase and objective color were evaluated daily. Data were analyzed in SAS as a repeated-measures mixed model with main effect of treatment and day. Deli brand was included as a block. Means were sliced by day, and significance was determined at P < 0.05.

Results: In turkey, no treatment × day effect (P > 0.90) was observed for lightness (L*) or 570/650 nm ratio. No treatment × day effect was observed for redness (a*). CON turkey was 10.5% redder than L-UVC and H-UVC on day 2 of display (P < 0.05), which did not differ from each other (P = 0.56). A treatment × day effect was observed for yellowness (b*) and chroma (C*), with treatment differences observed on days 1, 2, and 3 of display. However, by day 4, no differences (P > 0.38) in yellowness or chroma were observed between treatments. H-UVC turkey had a 7.7% more saturated color (C*) and was 8.2% more yellow on day 1 of display than L-UVC and CON turkey (P < 0.05). CON turkey color was 2.9% less saturated and 3.2% less yellow on day 1 of display than L-UVC turkey (P < 0.05). On days 2 and 3 of retail display, H-UVC turkey color was 3.4% and 3.3%, respectively, more saturated (C*) and 3.7% and 3.5%, respectively, more yellow (P < 0.01) than L-UVC and CON turkey, which did not differ from each other (P > 0.75). A treatment effect was observed for day 1 to day 5 ΔE (P < 0.03). H-UVC turkey had, on average, a 23.7% greater color change (ΔE) than L-UVC and CON (P < 0.01), which did not differ from each other (P = 0.08). There was a treatment × day effect observed for visual likelihood of purchase only on day 5 of display (P = 0.03). On day 5 of display, CON and L-UVC turkey had greater purchase intent scores than H-UVC turkey (P < 0.05) and did not differ from each other (P = 0.64). There was no treatment or treatment × day effect for ham visual likelihood of purchase, lightness (L*), redness (a*), or 570/650 nm ratio on any display day (P > 0.16). A treatment effect was observed for yellowness (b*) and day 1 to day 5 ΔE (P < 0.03). H-UVC ham was 3.8% more yellow than CON ham on day 1 of display (P < 0.01). CON ham had a 9.5% greater color change (ΔE) from day 1 to day 5 of retail display than H-UVC ham (P = 0.03). A treatment effect was observed for chroma (C*; P = 0.04). H-UVC ham had a 1.2% more saturated color (C*) than CON ham (P = 0.04).

Conclusion: Instrumental color differences were found between far-UVC–treated deli meat and nontreated deli meat, yet these differences did not translate to meaningful differences in likelihood of purchase for evaluators. Therefore, the far-UVC light treatment doses used in the present study would not be expected to detrimentally affect meat quality during retail shelf display. However, the authors observed deli turkey samples appeared to be very yellow immediately after far-UVC treatment with the color returning to near normal values prior to initiation of shelf-life study. For that reason, as well as the long treatment times required, far-UVC light treatment may not be practical for immediate use on fresh sliced deli meat in brick-and-mortar stores. However, far-UVC light treatment may have applications in large production plants as a postpacking microbial intervention or for use on deli counters and slicing equipment.

Funding Source: This work is supported in part by the US Department of Agriculture’s National Institute of Food and Agriculture Food Safety and Defense Program (2022-67017-36291).

Keywords: deli meat, ultraviolet, shelf life, ham, turkey.

113 Prediction of Beef Carcass Composition From Millimeter Radar Scans Using Data Augmentation, and Machine Learning Methods

Jacob McMillan*, Dale Woerner, Andres Mendizabal, Victor Sheng, Rohit Soni, and Blake Foraker, Texas Tech University, Lubbock, TX 79409, USA *jacob.mcmillan@ttu.edu

Introduction/Objectives: Many metrics have historically been used to determine the saleable yield of beef carcasses. Recent developments in technology have given us the opportunity to reevaluate how we determine saleable yield. Computed tomography (CT) scans are a useful tool in determining the composition of carcasses through the differentiation of tissues like muscle, fat, and bone. This is a very accurate, noninvasive method of determining total carcass composition. Our first objective was to build a machine learning model to process spatial point cloud data obtained from millimeter radar measurement of live cattle to accurately predict the CT composition of beef carcasses. A subsequent part of training the model was to digitally replicate the point clouds using data augmentation techniques to train the machine learning model with a larger sample size. The second objective of this study was to validate the CT composition model against its directional relationship with saleable subprimal yield.

Materials and Methods: To obtain training data, cattle (n = 95) were harvested at the Washington State University (WSU) Meat Laboratory. Millimeter radar measurements (SizeR, Geissler Corporation, Minneapolis, MN) of fed steers and heifers and mature cows were taken immediately prior to harvest. Live weight was obtained using a certified scale immediately after scanning with the radar system and before stunning. After chilling, carcass left sides were separated into primal cuts. These cuts were CT scanned (Aquilion 16, Toshiba Medical Systems, Tokyo, Japan) at WSU Veterinary Teaching Hospital. The scans for each cut were imported as image sequences to ImageJ for data processing. Each sequence was converted to 32-bit, and a histogram of pixels binned at 2500 one-unit intervals from −500 to +1999 Hounsfield units (HU), was created. Muscle, fat, and bone were segmented by applying a curvilinear function to the pixel density across HU. Thresholds for each tissue were determined at inflection points on the function. A 3-dimensional convoluted neural network model (3D-CNN) was built in Python with the help of researchers from the Department of Computer Science at Texas Tech University. The model was designed to predict (output) CT volumes of muscle, fat, and bone tissues based on the point cloud data from each individual animal’s millimeter radar scan (input). To obtain testing data for the model, fed steers (n = 37) were harvested at West Texas A&M University Meat Science Laboratory. Millimeter radar measurements of live animals were taken immediately prior to harvest, and subprimal cutout data were collected. Although true CT volumes were not collected on these carcasses, their cutout yields were tested against the CT predictions of the 3D-CNN. Comparisons were made between predicted volumes and real cutout weights as well as percentages for each of those factors. All data analysis was done in RStudio software using Pearson correlations.

Results: On the training data set (n = 95), in which true CT volumes are a known variable, the model performed adequately. The 3D-CNN’s predicted percentages of muscle, fat, and bone were moderately related to true values, with R² of 0.47, 0.51, and 0.51, respectively. Additionally, predicted total carcass volumes were also moderately related to true values with R² of 0.52. Although the training model was not developed to directly predict saleable yield, it was believed that saleable yield would be directionally related to CT tissue composition. Of carcass tissues, bone predicted from millimeter radar measurements was most related to actual CT bone weight (R² = 0.12). Additional modeling and data processing are required to achieve higher accuracies in validating the use of morphological measurements to predict tissue volumes.

Conclusion: Although the 3D-CNN model demonstrated moderate effectiveness in predicting CT composition of beef carcasses, the validation of such a model on a testing data set indicated opportunity for improvement. Adjustments to model’s architecture are still ongoing, and further use of data augmentation and data preprocessing could provide greater accuracy. The use of a machine learning model to predict not only composition but also saleable yield of beef carcasses is very possible with current technology; however, considerable work remains to have more confidence in such a model.

Funding Source: Funded by The Beef Checkoff.

Keywords: neural network, yield prediction, computed tomography.

114 Impact of Different Processing Plants and Further Processing Facilities on Ground Beef Color Stability and Reducing Ability

Ashley Rivera¹*, Cameron Catrett¹, Morgan Denzer¹, Edward Yancey², Jacob R. Tuell³, and Derico Setyabrata¹, ¹Department of Animal Science, University of Arkansas, Fayetteville, AR 72701, USA, ²Tyson Foods Inc., Springdale, AR 72762, USA, ³School of Agricultural Sciences, Northwest Missouri State University, Maryville, MO 66468, USA *ashpau27@gmail.com

Introduction/Objectives: Color deterioration is a major meat quality defect that often leads to product rejection and decreased retail sales. Color stability is influenced by the oxygen consumption rate and metmyoglobin-reducing ability of the product. Although it has been documented that color quality and shelf life are highly dependent on intrinsic meat characteristics, information on the influence of postmortem environment in color quality remains limited. Hence, this study aims to evaluate how different production plants and processing facilities affect the color quality of ground beef.

Materials and Methods: Ground beef chuck chubs (80% lean, 20% fat) from 3 different batches were collected from 2 beef processing source plants managed by the same company (SP1 and SP2, n = 3/source plant). Chubs were collected from ground beef produced 3 d prior to the collection. Chubs were collected simultaneously from both source plants on the same day to ensure similar postprocessing product age and then transported to the University of Arkansas (UARK; ∼7.5 h from each plant). Samples were placed in coolers with ice, and the temperature was checked regularly to ensure product temperature did not reach higher than 4°C. The next day, the samples were randomly assigned for further processing at either UARK or the Northwest Missouri State University (NWMSU) facility. Samples designated to NWMSU facilities were then transported to the facility in a manner similar to that previously described (∼5.5 h). All samples were further processed simultaneously in each facility by regrinding samples using an identical 3-mm plate to form 450-g ground beef loaves (n = 2/batch). Samples were overwrapped with oxygen-permeable polyvinyl chloride film on foam trays with soaker pads. Samples from NWMSU were then transported back to UARK in a similar manner as previously described, with a shelf in the cooler to reduce the impact of product stacking. All samples (UARK and NWMSU) were simultaneously displayed at the UARK facility immediately upon arrival for 5 d in a simulated retail display under light. The redness (a*), chroma, oxygen consumption rate (OC), and metmyoglobin-reducing ability (MRA) were determined for all samples before and after display using HunterLab MiniScan. The study design was a randomized complete block with split-split-plot arrangement, and the study was repeated twice. The processing source plants, further processing facilities, display day, and their interactions were fixed effects, whereas batch was the random effect. The collection period served as the block, the processing source plants as the whole plot factor, the further processing facilities as the split-plot factor, and the display day as the split-split-plot factor. Data were analyzed using the lme4 and emmeans packages in RStudio. Means were separated (F-test, P < 0.05) by least significant differences.

Results: Significant color source plant and day interaction was observed for both redness (a*) and chroma, exhibiting reduced color stability on samples from SP2. A similar redness value was observed at day 1 (d1) of the display regardless of the source plant (P > 0.05). However, SP1 had a greater a* at day 5 (d5) of the display compared with SP2 samples (P < 0.05). For chroma, SP2-d1 had the greatest color saturation, followed by SP1-d1, SP1-d5, and SP2-d5, which had the lowest color saturation (P < 0.05). The MRA of the samples was significantly impacted by a source plant × further processing facility × day interaction. At d1 of display, the SP2-UARK samples exhibited lower reducing ability compared with SP2-NWMSU samples (P < 0.05), although not different compared with both SP1-UARK and SP1-NWMSU samples (P > 0.05). At d5 of the display, however, SP1 samples were observed to have greater reducing ability compared with SP2, regardless of the further processing facilities (P < 0.05). A significant source plant × day interaction was observed on the OC of the samples. Although not different on d1 of display (P > 0.05), SP1 exhibited greater OC compared with SP2 at the end of the display (P < 0.05), potentially contributing to the greater color observed in SP1. Similarly, a further processing facility × day interaction significantly impacted the OC of the product, showing a lower OC on NWMSU-d5 samples compared with all other treatments (P < 0.05).

Conclusion: The results of this study suggested that the color stability and reducing capability of ground beef were greatly influenced by the processing source plant. Further processing facilities only minimally impacted the color quality, mainly by altering the OC and MRA of the product. Investigation on the impact of microbial community alterations on the color quality is currently in progress.

Funding Source: Research coordinated by the National Cattlemen’s Beef Association, a contractor to the Beef Checkoff.

Keywords: color stability, ground beef, shelf life, reducing ability, postmortem environment.

115 Characterizing the Reflectance and Scattering Properties of Psoas Major and Longissimus Lumborum Muscles During Retail Display Using Noncontact Diffuse Reflectance Spectroscopy and Optical Coherence Tomography

Daqing (Daching) Piao¹*, Scott Mattison¹, Ardalan Farazmand¹, Nafiseh Farahzadi¹, Anuj Sharma², and Ranjith Ramanathan², ¹School of Electrical and Computer Engineering, Oklahoma State University, OK 74078, USA, ²Department of Animal and Food Sciences, Oklahoma State University, Stillwater, OK 74078, USA *daqing.piao@okstate.edu

Introduction/Objectives: Meat color is an important sensory attribute that influences purchasing decisions. Surface measurement of color is based on the spectral changes in diffuse light reflection. More specifically, spectral characteristics are influenced by the absorption of chromophores such as myoglobin. We recently developed and published a noncontact diffuse reflectance spectroscopy (DRS) approach to quantify metmyoglobin formation during storage. Surface measurement of diffuse light reflection is also affected by the scatterers in the meat matrix, including muscle fibers. Therefore, assessing both absorption and scattering of the muscle may enable a more robust prediction of discoloration. The optical coherence tomography (OCT) provides high-resolution, cross-sectional imaging of biological tissues, most commonly in medical diagnostics. The objective of the current study was to use muscles of contrasting color stability (longissimus lumborum [LL] and psoas major [PM]) to investigate a combination of noncontact DRS and OCT imaging to understand light reflectance and scattering properties during retail display.

Materials and Methods: Eight USDA Choice Porterhouse steak sections (containing LL and PM muscles) were purchased from local purveyors. The muscles were approximately 21 d postmortem. Muscles were sliced into 2.54-cm-thick Porterhouse steak, packaged immediately after cutting in white Styrofoam trays with socker pads, and overwrapped with polystyrene polyvinyl chloride film (15,500–16,275 cm³, O₂/m²/24 h at 23°C). All steaks were placed in a coffin-style retail display case for up to 4 d at 2±1°C, during which there was continuous LED lighting at 1,100 lux. All packages were rotated daily to minimize the effects of variation in light intensity or temperature due to location. Surface color, myoglobin form, and scattering of the steaks were measured repeatedly using a handheld colorimeter, noncontact DRS, and OCT during 4 d of storage. Raw instrumental color of the steaks was measured daily using a HunterLab 4500L MiniScan EZ spectrophotometer (2.5-cm aperture, illuminant A, and 10° standard observer angle). The instrument color was measured at 3 randomly selected positions on both the PM and LL muscles. Both a* values and percentage metmyoglobin from reflectance measurements were used to characterize color changes with storage time. The PM and LL muscles of each steak were measured by noncontact DRS at 5 randomly selected positions on each muscle to quantify surface myoglobin forms. Subsequently, the PM and LL muscles of each steak were placed under noncontact OCT to image at 5 randomly selected positions on each muscle. To compare scattering properties of 2 muscles, the penetration depth (for signal-to-noise ratio > 2) and signal decay rate (dB/mm) of OCT was characterized. The experimental design was a randomized complete block. The loin from each animal served as a block—that is, each loin was used as a random term. The main effects include muscle type, days of retails display, and their interactions. The data were analyzed using the Proc Mixed Procedure of SAS and considered significant at P value less than 0.05. The Repeated option in MIXED was used to model the covariance structure caused by repeated measurements on the same sample during storage.

Results: There was a significant muscle type × storage time interaction (P < 0.05) result for metmyoglobin and a* values. As expected, PM steaks discolored more (P < 0.05) than LL on day 4 of storage. HunterLab MiniScan and noncontact DRS had a similar trend, indicating discoloration with storage time. The main effect of muscle type (P < 0.05) was significant for scattering properties. Psoas muscles had significantly different scattering properties (P < 0.05) than LL muscles. For example, the depth of penetration of PM was 2.26 ± 0.41 mm compared with (P < 0.05) 1.5 ± 0.20 for LL.

Conclusion: Noncontact dual-modality DRS and OCT have been applied to assess the discoloration of PM and LL. Noncontact DRS revealed changes of myoglobin forms consistent with those estimated by using measurements of the HunterLab MiniScan spectrophotometer. The PM muscles showed greater penetration of OCT signals accompanied with slower rate of signal decay, indicating a more isotropic scattering that may suggest smaller fiber sizes. This work has demonstrated using OCT to provide scattering-related depth-resolvable muscle morphology information that is inaccessible to noncontact DRS. Developing novel tools will help with understanding meat discoloration and minimize losses from wasting discolored beef.

Figure 1.

(Left): Metmyoglobin assessed using contact colorimeter and non-contact diffuse reflectance spectroscopy over day 0 to day 4, between PM and LL muscles. (Right) Penetration depth and signal to noise ratio of the back-scattered light measured by optical coherence tomography over day 0 to day 4, between PM and LL muscles.

Funding Source: US Department of Agriculture National Institute of Food and Agriculture (100005825) (2022-67017-36538) grant program.

Keywords: myoglobin, DRS, OCT, PM, LL.

116 Inclusion of Lubabegron Fumarate and Betaine in Beef Feedlot Diets and Impacts on Carcass Characteristics, Water-Holding Capacity, Tenderness, and Shelf Life

Amy Volk¹*, Kendall Swanson¹, Christy Finck¹, Kiersten Gundersen¹, Wanda Keller¹, Jacob Arntzen¹, Jessica Syring¹, Kasey Maddock-Carlin¹ and Zach Carlson², ¹Animal Sciences, North Dakota State University, Fargo, ND 58105, USA, ²Danisco Animal Nutrition and Health, Cedar Rapids, IA 52404, USA *amy.l.volk@ndsu.edu

Introduction/Objectives: Lubabegron fumarate (LUB), a β-adrenergic modulator used in beef feedlot diets, has been shown to improve lean beef yields but may reduce marbling scores and tenderness. Conversely, betaine (BET), a naturally occurring osmolyte and methyl donor, has been shown to increase fat deposition in beef cattle. Furthermore, betaine supplementation has demonstrated improvements in tenderness and cook loss in lamb and pork, although research on its effects on beef quality is limited. The objectives of this study were to evaluate the combined effects of LUB and BET supplementation on beef carcass characteristics, meat quality, tenderness, and shelf life of beef striploins.

Materials and Methods: All animal procedures were approved by the North Dakota State University (NDSU) Institutional Animal Care and Use Committee (Protocol #20240033). Fifty-three steers (476 ± 5.3 kg initial body weight), predominantly of Angus and Simmental breeding, were stratified by weight and randomly assigned to treatment in a 2 × 2 factorial arrangement, wherein diets were supplemented with or without LUB (0.032% of dry matter [DM] for 56 d, starting 63 d before slaughter, followed by a 7-d withdrawal) and supplemented with or without BET (0.28% of DM for 7 d before slaughter). Steers received a growth-promoting implant (200 mg trenbolone acetate, 20 mg estradiol 17β+, and 29 mg tylosin tartrate; Elanco Animal Health) and were fed a diet containing 10% forage (corn silage and grass hay) and 90% concentrate (dry-rolled corn, dried grains with solubles, urea, limestone, salt, vitamin and trace mineral mix, and monensin). Steers were transported to a commercial beef processing plant on 2 different days. Carcass data (hot carcass weight [HCW], dressing percentage, ribeye area, 12th-rib backfat, KPH, and marbling score) were collected, and US Department of Agriculture (USDA) Final Yield Grade was determined; striploins (Institutional Meat Purchase Specifications #180, N = 53) were transported to NDSU Meat Science Laboratory for further fabrication and analyses. The loins were aged in vacuum packaging for 14 d at 4°C. Loins were fabricated into four 2.5-cm-thick steaks for further analysis. Tenderness was evaluated by Warner-Bratzler shear force (WBSF) on day-14 and day-21–aged steaks, with cook loss percentage calculated. Drip loss was measured with 14-d–aged, 50-g samples that were either suspended for 48 h or were stored in plastic storage bags for 6 d. Simulated retail display was evaluated on day-14–aged steaks placed on Styrofoam trays overwrapped with PVC, displayed in a retail cooler for 14 d where daily measurements of L*, a*, and b* were taken with a Minolta colorimeter. Data were analyzed using PROC MIXED in SAS as a randomized complete block design for effects of treatments and their interaction, with initial weight as a covariate for HCW and dressing percentage and marketing date as the covariate for all other traits. Means were considered significant when P value was less than 0.05.

Results: LUB increased (P = 0.03) HCW, and there was a tendency for an interaction between LUB and BET on HCW (P = 0.07) and dressing percentage (DP; P = 0.06), in which steers fed BET tended to have higher HCW and DP when also fed LUB. LUB decreased (P < 0.05) marbling score and USDA Yield Grade and increased (P = 0.03) ribeye area. BET increased (P < 0.05) USDA Yield Grade and 12th-rib backfat. LUB increased (P < 0.02) 14-d purge loss in boneless striploins. BET tended (P < 0.08) to decrease purge loss and drip loss. Neither LUB nor BET impacted (P > 0.05) kidney, pelvic, and heart fat, cook loss, or water loss. Striploins aged for 14 d were not impacted (P > 0.05) by LUB or BET for WBSF; however, d-21 striploins had greater (P < 0.01) shear force values when LUB was fed. LUB and BET did not affect (P > 0.05) L* values on steaks displayed for 14 d. However, LUB decreased (P < 0.05) a* values after day 10. When LUB was supplemented, BET decreased (P < 0.03) a* and b* on day 2 of retail display.

Conclusion: LUB supplementation improved carcass yield but negatively impacted tenderness and increased purge loss. BET supplementation tended to reduce purge loss and may help mitigate some of the LUB-related moisture loss. However, BET increased backfat, leading to higher USDA Yield Grades. Although LUB decreased redness of steaks in simulated retail display, this effect was not apparent until after day 10 beyond typical retail display durations.

Funding Source: College of Agriculture, Food Systems, and Natural Resources, North Dakota State University, Fargo, North Dakota, and Danisco Animal Nutrition and Health, Cedar Rapids, Iowa.

Keywords: lubabegron, betaine, beef, quality, shelf life.

117 Evaluating Beef Conformation as a Predictor of Carcass Cutout Value

Mark Miller and Anna Carlock, Department of Animal and Food Sciences, Texas Tech University, Lubbock, TX 79409, USA *mfmrraider@aol.com

Introduction/Objectives: Standard grading systems emphasize ribeye area and subcutaneous fat thickness, but these traits alone may not capture the full spectrum of carcass composition. This study investigates whether paired carcasses that differ only in conformation score exhibit consistent differences in red meat yield (RMY) and cutout value and seeks to identify which readily measured linear dimensions best predict those differences. Improved understanding of conformation effects could refine carcass evaluation protocols and strengthen value-based marketing and breeding strategies.

Materials and Methods: Thirty-one carcass pairs (n = 62) were selected from the holding cooler chain at Nebraska Beef (Omaha, NE) immediately before grading. Pairs were matched based on similar hot carcass weight (HCW) and fat thickness to isolate conformation: 1—light muscled (dairy typed)—to 8—heavy muscled (double-muscled beef type)—and ribeye area as the primary variables. On each carcass, trained personnel recorded 23 linear measurements—including vertebral spans, aitch-bone lengths, rib spans, and limb girths—using a calibrated tape measure; mean values were used for analysis. In addition, each carcass was scanned using Polycam on an iPad to generate a high-resolution 3D surface mesh, capturing muscle bulge and curvature. Each carcass was then fabricated into US Department of Agriculture–standard primals (brisket, chuck, rib, loin, round) and subprimals; all saleable lean cuts, fat trimmings, and bone segments were weighed to ±1% accuracy. Total RMY (kg and %) and cutout value (USD per 100-lb HCW) were calculated. Paired t-tests (for normal data) compared high- versus low-conformation carcasses (α = 0.05).

Results: The difference in conformation score between paired carcasses ranged from 2 to 6 points, with nearly half of the pairs exhibiting a 4-point gap (48.4%). Although HCW, cold carcass weight, and fat thickness were effectively held constant (P > 0.24), high-conformation carcasses averaged a 1.74-cm²-larger ribeye area (P < 0.001) and a 0.63-unit improvement in yield grade (P < 0.001). Among the 23 linear measurements, 10 showed significant negative mean differences—indicating a more compact build in high-conformation carcasses. The largest reductions occurred in spans from the first rib to the aitch-bone (–6.27 cm, P < 0.001) and from the thoracic to lumbar vertebrae (–5.22 cm, P < 0.001). Smaller but still significant contractions were also seen in hip and loin regions (P < 0.02), whereas limb girths and certain rib cut lengths remained unchanged (P > 0.18). High-conformation carcasses delivered 1.92 percentage points more saleable lean meat (48.70% vs. 46.78%; P < 0.001) and added USD 7.12 per 100-lb carcass in cutout value (P = 0.0026). When broken down by primal, the round showed the most pronounced gains—0.85% higher yield (P = 0.0001) and USD 3.89 greater value (P = 0.0007)—whereas other primals exhibited positive but nonsignificant trends.

Conclusion: These results demonstrate that carcass conformation exerts a measurable impact on both RMY and economic value beyond traditional ribeye and fat metrics. Incorporating aitch-bone and vertebral span measurements—or even simple tape-measure surrogates—into grading could improve prediction of saleable meat and carcass worth. As an early phase of a larger project, this work underscores the potential for conformation-based selection and value-based marketing to enhance consistency, efficiency, and profitability throughout the beef supply chain. Future work will expand sample size, refine 3D imaging protocols, and explore genetic and management interactions that drive conformation and yield.

Funding Source: Texas Tech Department of Animal and Food Sciences.

Keywords: meat yield, conformation, cutout value.

118 Gut Microbiota of Channel and Hybrid Catfish Under Ammonia Stress Revealed by Full-Length 16S Ribosomal RNA Nanopore Sequencing

Guyue Tang^1,*, Wes Schilling¹, Peter Allen¹, Li Zhang¹, Chuan-yu Hsu¹, Ryen Comey¹, Emily Little², Daniel Joyce¹, Brian Ott², Geoff Waldbieser², and Xue Zhang¹, ¹Mississippi State University, Starkville, MS, USA, ²US Department of Agriculture (USDA)-Agricultural Research Service (ARS), Warmwater Aquaculture Research Unit: Stoneville, MS, USA *gt467@msstate.edu

Introduction/Objectives: The gut microbiome plays a vital role in catfish health, immunity, and nutrient absorption. In catfish aquaculture, environmental stressors, such as high ammonia concentration, may cause compromised growth and disease susceptibility. Although channel catfish (Ictalurus punctatus) historically dominated US catfish production, hybrid catfish (♂Ictalurus furcatus × ♀I. punctatus) have gained popularity due to faster growth, improved disease resistance, and higher yield. However, little is known about how ammonia stress affects the gut microbiota of these 2 fish types. Therefore, the objectives of this research are to (1) characterize the intestinal microbiota of channel and hybrid catfish under control and ammonia stress conditions and (2) determine the effects of fish types and ammonia stress on gut microbial composition and diversity.

Materials and Methods: Channel (n = 120) and hybrid (n = 120) catfish were raised in 200-L tanks for 5 wk under 2 ammonia conditions: control (0.8–0.9 mg N/L total ammonia [15–19 μg N/L unionized ammonia]) and high ammonia stress (13–16 mg N/L total ammonia [190–210 μg N/L unionized ammonia]). Each tank (n = 30 fish, 99–166 g per fish) was randomly assigned to 1 of the following 4 treatments: channel catfish control (CC), channel catfish under high ammonia stress (CA), hybrid catfish control (HC), and hybrid catfish under high ammonia stress (HA). A split-plot arrangement in a randomized complete block design, with 2 replications (occasions), was used to determine the impact of the 4 treatments on the gut microbiota. At harvest, intestine content (n = 12/treatment) from fish was collected for microbiome analysis. Total genomic DNA (gDNA) was extracted using the QIAamp PowerFecal Pro DNA Kit (Qiagen, Germantown, MD) with a modified protocol. The quantity and quality of extracted gDNA were checked using Nanodrop 2000 spectrophotometer (Thermofisher Scientific, Waltham, MA) and agarose gel electrophoresis, respectively. A quantitative polymerase chain reaction (PCR) assay targeting bacterial 16S ribosomal RNA (rRNA) gene was used to normalize bacterial DNA amounts, ensuring equal amounts of bacterial gDNA template for PCR amplification. Full-length 16S rRNA (V1–V9 region) were amplified using primers 27F and 1492R. After PCR product cleanup and quantification, 150 ng of purified PCR amplicon from each sample was barcoded using the Nanopore Native Barcoding Expansion 96 Kit (Oxford Nanopore Technologies, Oxford, UK). Pooled samples were purified with AMPure XP beads (Beckman Coulter, Brea, CA) ligated with native barcoding sequencing adapters and loaded onto Nanopore R10.4.1 flow cells (Oxford Nanopore Technologies) for a 24-h sequencing run on a GridION platform (Oxford Nanopore Technologies). Basecalling and demultiplexing were performed using Guppy. Sequences were processed in Emu v3.4.5 and analyzed in R (v4.3.2). α diversity was evaluated using Chao1 and Shannon indices, whereas β diversity was calculated using Bray-Curtis dissimilarity and visualized via principal coordinate analysis. Relative abundances at the genus and species levels were compared using the Kruskal-Wallis test with Dunn’s post hoc test and Benjamini-Hochberg correction.

Results: Hybrid catfish exhibited significantly greater species richness than channel catfish (Chao1, P < 0.05), whereas species evenness (Shannon index) did not differ (P > 0.05) among treatments. β diversity analysis based on species data indicated differences between fish species (P < 0.05) but not between ammonia treatments (P > 0.05). Channel catfish displayed more variability in microbial profiles, whereas hybrid catfish exhibited tighter clustering, suggesting a more uniform microbiota. At the genus level, the 9 most abundant genera identified across all samples were Lactococcus, Cetobacterium, Romboutsia, Plesiomonas, Exiguobacterium, Paracoccus, Deinococcus, Clostridium, and Gemmobacter. Lactococcus was the dominant genus across all treatments but was particularly more abundant (P < 0.05) in hybrid catfish (61.9% in HA and 40.0% in HC) than channel catfish (27.9% in CA and 21.7% in CC). In hybrid catfish, most other genera accounted for less than 10% of the microbial composition due to the nearly 50% dominance of Lactococcus. In contrast, channel catfish maintained a more evenly distributed microbiota. Notably, for the top 3 prevalent genera (Lactococcus, Cetobacterium, and Romboutsia), differences in the relative abundance were primarily driven by fish species rather than ammonia exposure. At the species level, the top 6 dominant bacterial species identified were Lactococcus lactis, Cetobacterium somerae, Romboutsia timonensis, Lactococcus garvieae, Plesiomonas shigelloides, and Exiguobacterium sp. AT1b. L. garvieae was relatively more prevalent (P < 0.05) in hybrid catfish (∼10% relative abundance) compared with channel catfish (∼5%). Given that L. garvieae is a known fish pathogen, its elevated presence in hybrid catfish may have health implications. Ammonia stress had a limited impact on microbiota diversity or community structure. Differences in the relative abundance for dominant bacterial taxa were primarily driven by fish type rather than ammonia exposure. The tighter clustering of microbial communities in hybrid catfish may reflect a response to suboptimal growing conditions.

Conclusion: This study demonstrates that host species is the primary determinant of gut microbiota composition in catfish, with hybrid catfish exhibiting higher species richness but lower microbial balance due to the dominance of L. lactis. In contrast, channel catfish maintained a more diverse and balanced microbiota with significant representation of C. somerae and R. timonensis, which may provide digestive and immune benefits. Although elevated ammonia levels negatively impaired the growth performance in both species, they did not significantly alter microbial diversity or community structure under the tested conditions. These findings highlight the stronger influence of host species over environmental factors in shaping the intestinal microbiome of catfish.

Funding Source: This research was supported by the US Department of Agriculture (USDA)-Agricultural Research Service (ARS) Mississippi Center for Enhancing Utilization and Safety of Catfish and Other Aquatic Food.

Keywords: gut microbiota, catfish, ammonia stress.

119 Exploring the Functional Role of Spoilage Bacterial Growth on Beef Longissimus Lumborum Color During Retail Display

Colton L. Smith*, Ifigenia Geornaras, Jessica L. Metcalf, Jessica E. Prenni, Robert J. Delmore, and Mahesh N. Nair, Colorado State University, Fort Collins, CO 80523, USA *coltonlevismith@gmail.com

Introduction/Objectives: Beef wastage due to discoloration during retail display results in an economic loss of more than $3.7 billion for the beef industry every year. The intrinsic biochemical basis for meat color and discoloration has been well characterized, but the role of extrinsic factors on meat discoloration is not fully understood. Specifically, the functional role of spoilage bacterial growth on meat color stability remains to be thoroughly investigated. Previous studies have indicated that the growth of spoilage bacteria during retail display results in a significant decrease in the color stability of aerobically packaged beef. The objective of this study was to explore the functional role of spoilage bacteria on fresh beef longissimus lumborum (LL) steak discoloration during retail display using a multi-omic approach to characterize the microbial composition, changes in bacterial metabolism, and changes in metabolites.

Materials and Methods: Ten (n = 10) US Department of Agriculture Select beef striploins (LL) were wet aged (2°C, 14 d). Following aging, they were decontaminated by immersion in boiling water. After decontamination, the boiled surface was aseptically removed, and loins were fabricated into 1-cm-thick steaks. Steaks were randomly assigned to a decontaminated control treatment (DCON) or were inoculated (∼4 log CFU/cm²; INOC treatment) on the upper, light-exposed surface with a mixture of 6 beef spoilage bacteria consisting of 3 Pseudomonas spp. and 3 lactic acid bacteria (LAB). The steaks were wrapped in oxygen-permeable film on soaker pad–lined foam trays and retail displayed for 8 d. One steak per treatment per striploin was analyzed daily for objective and subjective color, microbial load, lipid oxidation (thiobarbituric acid reactive substances [TBARS]), 16S ribosomal RNA (rRNA) gene sequencing, metatranscriptomics, and surface metabolomics. Objective color measurements (L*, a*, b*) were obtained with a HunterLab Miniscan. Six to 8 trained panelists evaluated surface redness on a scale of 1 to 8, with 1 being reddest, and percentage discoloration from 0% to 100%. The culture-dependent microbial analysis included determination of aerobic plate counts, Pseudomonas spp. counts, and LAB counts reported as log CFU/cm². The TBARS and pH were measured using the top 2 mm of the light-exposed surface of each steak. The pH was measured after homogenizing meat in water (1:5). The metabolite analysis was performed using gas chromatography–mass spectrometry. All INOC samples were analyzed for 16S rRNA gene sequencing. A subset of samples was analyzed by metatranscriptomics and metabolomics. Specifically, 4 samples from display days 3 to 6 representing both treatments from the same striploin were analyzed for metabolites. In contrast, metatranscriptomics analysis was conducted on the subset of INOC samples. Microbial DNA and RNA were extracted from steak surface rinsates. The 16S rRNA gene sequencing was analyzed using QIIME2 and R with the vegan and adonis packages. The metatranscriptomics data were analyzed using Humann 2.0, with KEGG Orthology, and MaAsLin3.0 package in R. All other parameters were analyzed in a mixed factorial model, using analysis of variance through the lme4 and emmeans packages in R, with carcass as a random variable. Results are presented as estimated marginal means, and α was set at 0.05.

Results: There was a treatment-by-day interaction (P < 0.05) for L*, a*, and b* values; lean color scores; and percentage surface discoloration. The L* values (lightness) were similar (P ³ 0.05) between treatments until day 5, after which INOC had lower L* values compared with DCON. The a* (redness) and b* (yellowness) values of the treatments were similar (P ³ 0.05) from days 0 to 4 but were lower (P < 0.05) in INOC compared with DCON on days 5 to 7. From days 5 to 7, panelists scored INOC LL steaks as darker red and more discolored (P < 0.05) compared with DCON steaks. There was a treatment-by-day interaction (P < 0.05) for microbial populations of all count types evaluated, with INOC having greater population levels throughout the display period. There was a display day effect (P < 0.05) for TBARS and pH, with both values increasing over the display period for both treatments. The metabolomic analysis indicated that there were 10 metabolites that had treatment-by-day interactions (P < 0.05). Among these, 5 were associated with carbohydrate metabolism, and 2 were associated with amino acid metabolism. Furthermore, the nitrogenous compounds hypoxanthine, xanthine, and urea increased (P < 0.05) from days 4 to 6 more rapidly in the INOC samples. Results from 16S rRNA gene sequencing of INOC samples indicated that α diversity decreased (P < 0.05) over the display period, as measured with Shannon’s, Simpson’s, and Inverse Simpson’s indices. Beta diversity, as evaluated with weighted UniFrac distances, was influenced (P < 0.05) by display day, with each of days 0, 1, 2, 3, and 4 having different (P < 0.05) β diversities. Conversely, display days 4 to 7 were similar (P ³ 0.05) to each other but had less diversity compared with days 0 to 3. Results for metatranscriptomics showed there were 1073 metabolic pathways with significant changes (P < 0.05) from days 3 to 6. Analysis of the pathways revealed a general shift in microbial pathway abundance over days 3 to 6 with substantial changes to energy metabolism pathways. In general, days 3 and 4 had a greater prevalence (P < 0.05) of carbohydrate metabolism-associated gene transcripts compared with days 5 and 6, which had a greater prevalence of amino acid–associated metabolism pathways detected. Furthermore, there was an increase in prevalence (P < 0.05) of lipid biosynthesis protein pathways from day 3 to 6.

Conclusion: Results from this study provide further evidence that bacterial growth during retail display can influence fresh beef discoloration. However, changes in oxidation or pH were not substantial enough to cause faster surface discoloration in the inoculated steaks. These results also indicate that the changes in the microbial metabolism from primarily carbohydrate utilization to amino acid utilization coincide with changes in the color stability of aerobically packaged beef LL steaks, suggesting that microbial metabolic functional changes are contributing to beef discoloration. Further research is needed to investigate the specific changes, especially concerning metabolites, to better elucidate the microbial function in discoloration in aerobically packaged fresh beef LL steaks.

Funding Source: Research coordinated by the National Cattlemen’s Beef Association, a contractor to the Beef Checkoff.

Keywords: beef color, shelf life, microbiome, metabolomics.

120 Effects of Dietary Citrate Supplementation on Muscle Metabolites of Rattus sp. Males for Potential Use as Livestock Models

MacKenzie G. Chapman*, Stephen B. Smith, Spencer B. Tindel, Jeffrey W. Savell, and Kerri B. Gehring, Texas A&M AgriLife Research, Texas A&M University, College Station, TX 77840, USA *mackenzie.chapman@tamu.edu

Introduction/Objectives: Citrate is an essential substrate for mitochondrial function, glycolysis, and fatty acid synthesis, acting as a main regulator of these processes. During the conversion of muscle to meat, glycolytic substrates undergo several reactions. Meat quality is largely dependent on these postmortem reactions, affecting rate of postmortem pH decline and ultimate pH. The enzyme 6-phosphofructokinase of glycolysis is inhibited by adenosine triphosphate, especially in the presence of citrate, which directs glucose-6-phosphate to glycogen production and depresses glycolysis. Supplementing exogenous citrate could have an impact on cellular citrate concentrations, indicating whether citrate supplementation could promote various cellular pathways of importance to meat quality. The objectives of this study were to determine whether dietary citrate supplementation (1) has an impact on cellular glycolytic metabolites in rat liver, M. soleus, M. gastrocnemius, and longissimus dorsi and 2) impacts adipose tissue accumulation and body weight.

Materials and Methods: This experiment was performed under Texas A&M University Animal Use Protocol number 2024-0056 for the ethical treatment of rats. Genetically similar Rattus sp. males (n = 24) were divided into 3 treatment groups (n = 8 rats/group): (1) CONTROL (sugar water), (2) LOW (1.5% citrate in water), and (3) HIGH (3% citrate in water). To prepare the water solutions, respective amounts of citric acid (LOW: 0.015 g/mL; HIGH: 0.03 g/mL) were added and stirred, and pH was adjusted to 7.35 to 7.40. Additionally, all water solutions contained 17% sugar (340 g per 2000 mL) to entice consumption. Each group underwent treatment for a 2-wk period, and body weight was measured daily. After 2 wk, rats were anesthetized with sodium pentobarbital (60 mg/kg) and exsanguinated using the guillotine method. Immediately following exsanguination, the epidydimal fat pad, liver, M. soleus, M. gastrocnemius, and longissimus dorsi were dissected and immersed in liquid nitrogen. Samples were transported to the Texas A&M Meat Science Laboratory and stored in −80°C freezer until subsequent analyses of tissue metabolites and weight measurements. Frozen tissue samples were weighed, dissolved in 5 mL of 50% perchloric acid, neutralized with 200 μL of potassium bicarbonate, and then centrifuged at 1500 rpm for 30 min. The supernatant fraction of each sample was transferred into centrifuge tubes for subsequent metabolite analysis. Lactate and citrate levels were analyzed with a Beckman DU-7400 spectrophotometer (Palo Alto, CA) set at 339 nm, following a modified version of Bergmeyer (1974). Data were analyzed with JMP Pro (v. 16.0.0; SAS Institute, Cary, NC). The Fit Model Standard Least Squares function was used for analysis of variance comparisons, and mean comparisons were conducted using Tukey’s test at an α of P < 0.05.

Results: With the epidydimal fat pad weight, there was a treatment effect (P < 0.0001), wherein the HIGH group had the lowest fat pad weight (20.5 ± 4.3 g), and the LOW and CONTROL groups did not differ (P = 0.64) (Table 1). For final weight, there was a treatment effect (P < 0.0001). The CONTROL and LOW groups did not differ at the final weight post–2-wk treatment period (P = 0.52); however, the HIGH group had the lowest final weight (Table 1). For lactate, there were treatment (P = 0.0007) and muscle (P = 0.0002) effects. For treatment, the HIGH group had the highest levels of muscle lactate, and the CONTROL and LOW groups did not differ (Table 1). For tissue type, the M. soleus had the highest (P < 0.05) level of muscle lactate level (0.46 ± 0.04 micromole/g), whereas the liver, M. gastrocnemius, and longissimus dorsi did not differ in lactate concentration (P > 0.05). For citrate level, there was a treatment effect (P = 0.024). The HIGH group had the highest level of citrate in tissues, whereas the CONTROL and LOW groups did not differ in citrate concentration (Table 1).

Conclusion: Results from this study show that citrate supplementation in the drinking water of Rattus sp. males over a 2-wk trial period had a significant effect on muscle concentrations of lactate and citrate. These preliminary findings indicate that citrate supplementation in live animal models may present an avenue to alter postmortem meat quality traits, as cellular metabolites that fuel metabolic pathways for oxygen consumption and mitochondrial function in postmortem muscle. Citrate supplementation may offer a way to impact postmortem pH decline, which could impact meat quality traits, such as color stability and protein functionality. Further research is needed to determine the effects of dietary citrate supplementation on postmortem pH and muscle color.

Funding Source: This study was funded, in part, by Texas A&M AgriLife Research.

Keywords: citrate, pH, glycolysis, meat quality, postmortem.

121 Harvest Co-Product Yields of Purebred Angus Compared With Angus × Holstein Crossbred Steers

Thomas C. Petit*, Trent E. Schwartz, Loni W. Lucherk, and Ty E. Lawrence, West Texas A&M University, Canyon, TX 79016, USA *tpetit@wtamu.edu

Introduction/Objectives: Purebred dairy cattle are typically discounted when marketed to beef processors, due to unfavorable carcass muscling attributes, ergonomic carcass length complications, and marketing limitations. Dairy-crossbred cattle allow producers to add value to the dairy industry by providing a product that reduces discounts and improves marketability. Angus and Angus × Holstein cattle differ in genetic composition, thus potentially impacting the yield outcomes of co-products at harvest. Our objective was to quantify absolute weight and percentage yield similarities and differences for harvest co-products between purebred black Angus (A) and Angus × Holstein (AH) steers.

Materials and Methods: Cattle (N = 40), consisting of A steers (N = 20) and AH steers (N = 20) originating from 4 different feedlots, were harvested on 4 different days at the West Texas A&M University Caviness Meat Science & Innovation Center. All cattle were immobilized via captive bolt stunner and were weighed before and after exsanguination. Hides were removed from carcasses with the aid of pneumatic dehiders. The gastrointestinal tract and internal organs were removed from the carcass; the 4-compartment stomach and small and large intestines were separated, washed clean, and weighed. Omental and mesenteric fat was removed from the gastrointestinal tract and weighed. Absolute weights of all harvest co-products removed from the carcass throughout the harvest process were recorded. Hot carcass weights were observed and recorded to calculate the dressing percentage of each animal. Empty body weight (EBW) was calculated by adding all carcass and noncarcass components minus fill. Yield of each co-product was also calculated as a percentage of empty body weight. Data were analyzed via mixed models using a completely randomized design with an α level set to 0.05; breed type was the main effect, and feedyard was the random effect.

Results: Stun weight of AH steers was 9.9% heavier than A steers (P < 0.01; 720.47 kg vs. 655.81 kg) at harvest. Fill of AH cattle was 22% greater (P < 0.01; AH = 43.73 kg, A = 35.79 kg) than A steers; removal of fill yielded 9.1% heavier EBW for AH steers (P < 0.01; 676.84 kg vs. 620.12 kg) compared with A steers. Additionally, AH steers had 7.7% heavier hot carcass weights (P < 0.01; 465.58 kg vs. 432.11 kg) but lower dressed yields (P < 0.01; 64.57% vs. 65.83%) than A steers. No difference (P ≥ 0.31) between cattle types was observed for metacarpals, oxlips, or hide as a percentage of EBW. No difference (P ≥ 0.11) was observed between cattle types for initial head weight, oxlips, head without tongue, sternomandibluaris, cheek meat, untrimmed tongue, larynx, hyoid bone, tonsils, weasand, tongue root, salivary glands and associated fat, head meat, trimmed head, brain, or pituitary gland when expressed as a percentage of EBW. No difference (P ≥ 0.13) between cattle types was detected for tendons, oxtail, spinal cord, thymus, total blood, penis, fat trim, and muscle trim expressed as a percentage of EBW. No difference (P ≥ 0.24) existed for reticulum, omasum, abomasum, small intestine, large intestine, bung, bung trim, heart fat, pericardium, aorta, lungs, trachea, esophagus, liver with the gallbladder removed, pancreas, and bladder with contents when expressed as a percentage of EBW. Metatarsals (P < 0.01; 0.76% vs. 0.69%), kidney-pelvic-heart fat (P < 0.01; 2.62% vs. 2.17%), omental fat (P < 0.01; 3.72% vs. 3.23%), and mesenteric fat (P = 0.02; 3.04% vs 2.74%) represented a greater proportion of EBW for AH steers than A steers. Additionally, AH steers tended to have heavier kidneys (0.21%), heart (0.49%), and spleen (0.18%) than A steers (P ≤ 0.06; 0.19%, 0.46%, 0.16%) when expressed as percentage of EBW. Trimmed tongue (P = 0.05; 0.18% vs. 0.17%) and rumen (P = 0.04; 1.86% vs. 1.71%) of A steers represented a greater percentage of EBW than AH steers.

Conclusion: Because of the larger body weight of AH steers, most weights were heavier than those collected from A steers. Most harvest co-products were a similar percentage of EBW between cattle types. The few differences observed between AH and A steers were heavily influenced by increased proportion of bone, fat, and visceral organ composition of AH steers. However, A steers yielded higher dressed carcass percentages than AH steers.

Funding Source: Funding for this project was provided by the Iowa Beef Industry Council’s State Checkoff Program.

Keywords: bovine, breed, carcass, slaughter, weights.

122 Impact of in Utero Heat Stress on Meat Quality in Barrows From Heat-Tolerant and Heat-Sensitive Sows

Dylan Metzel¹*, Jin-Kyu Seo¹, Dong-Jin Shin¹, Evie Sierra¹, James Markworth¹, Yuan H. Brad Kim¹, Caitlyn Sullivan², and Jay S. Johnson², ¹Purdue University, West Lafayette, IN 47907, USA, ²University of Missouri, Columbia, MO 65211, USA *dmetzel@purdue.edu

Introduction/Objectives: In utero heat stress (IUHS) is a growing concern in the swine industry, as high temperatures increase the risk of fetal heat stress exposure. Such conditions may lead to offspring with inferior meat quality attributes; however, research on these effects remains limited. The objective of this study was to determine the impact of IUHS on meat quality attributes in barrows derived from sows with different genetic heat tolerance (heat sensitive vs. heat tolerant), providing insights into meat quality variations associated with IUHS.

Materials and Methods: The pig treatment groups included a genomically heat-tolerant population exposed to in utero thermoneutral (IUTN) conditions (constant 17°C to 22°C chamber; TTN; n = 9), a genomically heat-tolerant population exposed to IUHS conditions (cyclic heat stress [HS] temperatures of 26°C at night to 32°C during the day applied to pregnant gilts; THS; n = 9), a genomically heat-sensitive population exposed to IUTN conditions (STN; n = 9), and a genomically heat-sensitive population exposed to IUHS conditions (SHS; n = 9). From day 60 of gestation to farrowing, all pigs were exposed to IUTN conditions, and from birth to 6 mo of age, all pigs were exposed to thermoneutral conditions and raised in group pens under normal commercial production conditions. At 6 mo of age, 36 barrows were slaughtered at the Purdue University Meat Laboratory. At 1-d postmortem, 9 pairs of 2 muscles, including the M. longissimus thoracis et lumborum (LL) and M. psoas major (PM), were obtained from carcasses from each group. Each muscle pair was vacuum packaged and randomly assigned to 1 of 2 aging times (1 and 10 d). Upon aging, chops were cut, overwrap packaged with polyvinyl chloride film, and displayed under light for 7 d. Water holding capacity (WHC) and Warner-Bratzler shear force (WBSF) were determined, along with muscle fiber type determination. All traits were analyzed using least-squares means in the PROC GLIMMIX procedure of SAS 9.4, with post hoc comparisons conducted using the Tukey-Kramer test (P < 0.05). In the statistical model, treatment, aging time, and their interaction were considered fixed effects, whereas each animal serves as a block and a random effect.

Results: Drip loss in the LL muscle was significantly higher in the IUHS groups (THS, 4.73%; SHS, 5.26%) than in the IUTN groups (TTN, 4.01%; STN, 4.03%) (P < 0.05). TTN had a significantly lower centrifugal loss than the other treatments in LL. No significant treatment effects on WHC were found in PM. The redness (CIE a*) and color intensity (chroma) in PM were lowest in SHS compared with other treatments (P < 0.05). During the 10-d display period, the CIE a* value was higher in TTN than SHS in both the LL (5.18 vs. 4.21) and PM (11.13 vs. 9.51) (P < 0.05). Similarly, the hue angle was lower in TTN than SHS in the LL (68.64 vs. 78.29) and PM (52.95 vs. 57.85), indicating better color stability in TTN (P < 0.05). At 2 d postmortem, TTN had lower WBSF than THS and SHS in LL (P < 0.05). WBSF in PM was not affected by treatments (P > 0.05). The LL of the IUHS group had a higher type IIX fiber ratio than that of the IUTN group (40.35% vs. 30.52%; P < 0.05).

Conclusion: These results suggest a muscle-specific response to IUHS in quality attributes of meat from barrows, with IUHS having more pronounced negative impacts on WHC, instrumental tenderness, and color stability of LL compared with PM. This may be partially attributed to the changes in muscle fiber type composition under IUHS. Heat stress sensitivity of the sows may exacerbate the negative impacts of IUHS on the offspring. Further research is warranted to investigate mitochondrial characteristics and changes in lipidomes and metabolomes of muscles affected by IUHS.

Funding Source: US Department of Agriculture (USDA)–Agriculture and Food Research Initiative (AFRI) National Institute of Food and Agriculture (NIFA) (2023) Grant and Brain Pool Korea.

Keywords: in utero heat stress; different breeding; muscle fiber type.

123 Efficacy of Natural and Synthetic Antioxidants on Color and Shelf Life of Ground Beef Patties in Retail Display

Vallie Yancey¹, Ashlyn Davis¹, Cameron Catrett², Peyton Arnold², Ashley Pitti², Paul Dahunsi², Janeal Yancey³*, Edward Yancey II⁴, and Derico Setyabrata², ¹Huntsville High School FFA, Huntsville, AR 72740, USA, ²Department of Animal Science, University of Arkansas, Fayetteville, AR 72701, USA, ³Department of Animal Science, University of Arkansas System Division of Agriculture, Fayetteville, AR 72701, USA, ⁴Tyson Foods, Springdale, AR 72762, USA *jws09@uark.edu

Introduction/Objectives: Ground beef is a very versatile and dynamic product, but it comes with shelf-life and discoloration challenges. Processors are trying to alleviate these issues by using both natural and synthetic antioxidants to improve shelf life in the retail case. With consumer concerns about the use of synthetic ingredients in food, it is pertinent to find natural alternatives to synthetic antioxidants. The objective of this study was to understand the efficacy of synthetic and natural antioxidants on ground beef shelf-life attributes.

Materials and Methods: Previously frozen ground beef (80% lean) was obtained from commercial processing plants, equally allocated into 3 batches, and assigned to 1 of 3 treatments, including untreated control (CON), 0.25% rosemary extract (RSM), or 0.02% butylated hydroxide (BHA). Ground beef was mixed in a table-top mixer for 1.5 min, formed into 125-g patties, and packed on foam trays with polyvinyl chloride overwrap and an absorbent pad. Packages were placed in simulated retail display under continuous LED lighting in an open-front multideck display case for 5 d. Objective color (L*, a*, b*, hue angle, and chroma) was measured on 2 patties every 24 h throughout display using a MiniScan EZ spectrophotometer. On display days 1 and 5, patties were removed from display, analyzed for microbial enumeration, vacuum packaged, and frozen until 2-thiobarbituric acid reactive substances (TBARS) analysis. The study was a randomized complete block design with a split-plot arrangement. Batch served as the block, treatment as the split-plot, and display day as the sub-plot. Color data were analyzed as repeated measures while microbial enumeration and TBARS data were analyzed with a 3 × 2 factorial arrangement. Data were fit using a mixed model and analyzed using the lme4 and emmeans package in RStudio with the fixed effects of treatment, display day, and their interaction.

Results: Ground beef color quality decreased as expected throughout display, with patties becoming less red, with decreased chroma values and greater hue angles (P < 0.05). Patties treated with BHA were redder (a*) and yellower (b*) and had a greater color saturation (chroma) and decreased hue angle than CON patties (P < 0.05). RSM patties did not differ from CON patties for each objective color measurement (P > 0.05). There was a treatment × day interaction for oxidation (P = 0.01), wherein both BHA and RSM patties had decreased TBARS values on day 5 compared with CON patties (P < 0.01); however, all CON, RSM, and BHA day-1 TBARS values did not differ (P > 0.71). There was no treatment × day interaction nor treatment main effect for aerobic plate counts (P > 0.67); however, there was a day main effect in which day 5 samples had elevated pates counts compared with day 1.

Conclusion: Ground beef patties treated with BHA had increased color stability during 5 d of display compared with CON patties, whereas RSM patties were intermediate. Both RSM and BHA were equally effective in reducing oxidation compared with CON patties. Neither antioxidant treatment was effective at inhibiting aerobic bacterial growth in ground beef patties during display.

Keywords: antioxidant, BHA, beef, color, rosemary.

124 Influence of Maternal Genetic Line on Finishing Pig Carcass and Pork Quality Characteristics

Matt Schulte¹*, Caroline Mitchell¹, and Eli Gjerlaug Enger², ¹Topigs Norsvin, Meerendonkweg 25, 5216 TZ Den Bosch, The Netherlands, ²Norsvin, Storhamargata 44, 2317 Hamar, Norway *matt.schulte@topigsnorsvin.com

Introduction/Objectives: Carcass and meat quality characteristics are influenced by genetic selection criteria. Many studies have assessed the impact of the sire line on carcass and meat quality characteristics. However, limited studies have assessed the impact of the maternal contribution to these traits. It was hypothesized that maternal genetic lines impact finishing pig carcass characteristics and pork quality traits differently. Therefore, the objective of this study was to evaluate the influence of modern maternal genetic lines on finishing pig carcass and meat quality characteristics.

Materials and Methods: Weaned pigs originating from the same farrowing barn were tracked throughout finishing to assess carcass and meat quality characteristics. Maternal genetic lines included genetic line 1 (commercial hybrid sow line of Topigs Norsvin: TN70 [Landrace × Large White]) and another commercially relevant maternal line (genetic line 2; Landrace × Large White) bred to a Duroc sire line. Finishing pigs (n = 800 per genetic line) were tracked through a commercial plant in the Midwestern United States at the time of harvest. Hot carcass weights (HCW) were collected during 3 marketing events, and dressing percentages were calculated. Primal weights (bone-in ham, belly, bone-in and boneless loin) were collected from a subset of finishing pigs (n = 240 per genetic line). A subset of boneless loins (n = 120 per genetic line) was collected and transported to the University of Illinois meat lab (Champaign, IL) and aged for 14 d prior to measuring the following loin chop quality characteristics: National Pork Producers Council (NPPC) color, marbling, and firmness scores; ultimate pH, L*, a*, and b*; percentage cook loss; and Warner-Bratzler shear force. Sensory characteristics (tenderness, juiciness, and flavor) were evaluated on loin chops (n = 40 per genetic line) from 1 marketing date. Carcass data were analyzed using PROC MIXED of SAS 9.4 (SAS Institute Inc., Cary, NC) with fixed effects of genetic line and gender. For primal weight analysis, HCW was used as a covariate. Loin chop data analysis included fixed effects of genetic line, gender, and marketing date. Significance was denoted with a P value less than or equal to 0.05.

Results: Market pigs from genetic line 1 had greater hot carcass weights and yields. No significant differences in primal weight were found. Loin chop analysis identified that genetic line 1 had a greater NPPC marbling score and sensory juiciness. Genetic line 2 had a lesser b* value. No other loin chop quality characteristics differed between maternal genetic lines.

Conclusion: The results of this study demonstrate the influence maternal genetic lines can have on finishing pig carcass and loin quality characteristics. The use of precise phenotyping methods, such as computed tomography scanning and near-infrared spectroscopy, can help to further enhance selection efficiency in paternal and maternal lines for carcass and meat quality characteristics. Further investigation into the contribution of the maternal genetic line to other carcass and meat quality characteristics is warranted to continue identifying how modern maternal genetics may influence market pig carcass and meat quality traits.

Funding Source: None.

Keywords: pork quality, genetics, carcass quality.

125 The Effect of Blue Light on Beef Quality

Amelia M. Miller*, Spencer B. Tindel, Jeffrey W. Savell, and Kerri B. Gehring, Texas A&M AgriLife Research, Texas A&M University, College Station, TX 77840, USA *amelia.miller@tamu.edu

Introduction/Objectives: As technology advances, it is of interest to explore new methods of preserving beef quality and reducing food waste. An emerging technology used in the medical and food industries are light-emitting diodes (LED) within the blue light spectrum, which ranges from 400 to 480 nm. Blue-light LEDs are a low-cost, low-energy, environmentally safe technology that could provide benefits to the meat industry. Previous studies have explored the use of this technology on dairy, produce, and food contact surfaces; however, limited research exists on fresh beef. The objective of this study was to evaluate the effect of blue-light application on fresh beef quality.

Materials and Methods: Beef striploins (M. longissimus lumborum; n = 8) were sourced, aged for 21 d, faced, and cut into approximate 2.54-cm steaks until 80 steaks were achieved. Steaks were assigned to 1 of 5 experimental groups (0, 1, 3, 5, or 7 d) for a 7-d trial period, with each group consisting of 16 steaks (n = 80; 5 groups × 16 steaks per group). Day 0 steaks were evaluated for baseline data on objective and subjective color, pH, aerobic plate counts (APC) and thiobarbituric acid reactive substances assay (TBARS). The remaining steaks (n = 64) were assigned to LIGHT or NOLIGHT groups and stored under approximate 2°C refrigeration for their respective number of days. Steaks assigned to LIGHT (n = 32) were placed approximately 15.24 cm under 405 nm LED bulbs, whereas steaks assigned to the NOLIGHT group were placed under blackout curtains and served as the control. On their assigned experimental day, steaks (n = 16; 8 LIGHT + 8 NOLIGHT) were removed from the cooler and analyzed for the same attributes as day-0 steaks. Objective color was measured in triplicate using a calibrated colorimeter, and L*, a*, and b* values were recorded. Subjective color evaluation of lean color (1–8 scale), amount of lean discoloration (1–5 scale), and amount of browning (1–6 scale) was performed by a group of 8 trained panelists in accordance with American Meat Science Association guidelines. Color measurements were taken before and after 30-min bloom. Measurements of pH were taken using a calibrated handheld pH meter. For APC sampling, steak surfaces were swabbed using 3M sterile dry-sponges moistened with Butterfield’s Buffer and plated onto Petrifilm aerobic count plates using a 9-dilution method. APC plate films were incubated for 48 h prior to counting and conversion to logarithms. TBARS was used to measure lipid oxidation by evaluating ppm of malonaldehyde per kilogram. Data were analyzed using JMP Pro (v.16.0.0; SAS Institute, Cary, NC). The Fit Model Standard Least Squares function was used for analysis of variance, and mean comparisons were conducted using Tukey’s honestly significant difference when appropriate at an α of P value less than 0.05.

Results: LIGHT steaks remained under blue light for 1, 3, 5, or 7 d receiving 535.68 J/cm², 1,607.04 J/cm², 2,678.40 J/cm², or 3,749.76 J/cm² of energy dosages, respectively. For subjective color evaluations (Table 1), there was a significant (P < 0.05) interaction between treatment and day for all subjective color variables in both packaged and unpackaged steaks. For packaged steaks, lean color values were higher (P < 0.0001) for LIGHT day-7 steaks compared with all others across treatment and time. For lean color, LIGHT packaged steaks from days 0 and 1 did not differ (P > 0.05) from NOLIGHT packaged steaks on days 0, 1, 3, and 5. For browning, LIGHT packaged day 5 and day 7 steaks had higher (P < 0.0001) values when compared with all other groups, whereas LIGHT AND NOLIGHT steaks did not differ (P > 0.05) in browning values until day 3. Discoloration values of packaged steaks showed a similar trend, wherein steaks subjected to LIGHT on day 0 and day 1 did not differ (P > 0.05) from NOLIGHT steaks from days 0, 1, and 3. Furthermore, discoloration values for LIGHT steaks from days 5 and 7 were higher (P < 0.0001) than all other days for both LIGHT and NOLIGHT groups. These results indicate an effect from blue light occurring around day 3. There were no light treatment main effects on any CIE values measured in packaged or unpackaged steaks (P > 0.05). Furthermore, there were no light treatment effects (P > 0.05) on pH, APC, or TBARS analyses.

Conclusion: The results of this study showed that 405-nm blue LEDs had negative effects on the color of beef beginning around day 3 of the trial period. Although there were no light treatment effects on pH, APC, or TBARS values, subjective color changes due to light were shown. At this point in the study, steaks had received an approximate energy dose of 1,607.04 J/cm² of blue-light energy. High amounts of light energy were likely the cause of these negative color changes in steaks. Discoloration is undesirable to consumers and decreases a consumer’s willingness to purchase, leading to economic loss for the meat industry. Further research is needed to determine optimal wavelengths and treatment times on use of blue-light LEDs as a preservative for fresh beef.

Funding Source: Research was supported, in part, by Texas A&M AgriLife Research.

Keywords: quality, blue light, color, beef, steaks.

126 Effect Peracetic Acid Dips Post-Debone on Broiler Tenderloin Meat Quality When Marinated After 2 Days of Storage

Sarah E. Johnson¹*, Joaquin J. Esquivel¹, Adalyn M. Hanning², Tomi Obe¹, and C. M. Owens¹, ¹University of Arkansas, Fayetteville, AR 72701, USA, ²Har-Ber High School, Springdale, AR 72762, USA *sey003@uark.edu

Introduction/Objectives: Peracetic acid (PAA) is a common antimicrobial used in the poultry industry. For food safety purposes, poultry meat may be subjected to PAA at various times throughout processing, including after deboning using direct contact dips. This research aimed to evaluate the impact of varying dip frequency of PAA on broiler tenderloin quality when followed by storage and marination 2 d postdip.

Materials and Methods: Tenderloins were randomly separated into 5 treatments: negative control (no dipping [NC]), 1 water dip control (WC), 1 dip in PAA (PAA1), 3 dips in PAA (PAA3), and 5 dips in PAA (PAA5), using n = 45 per treatment over 3 replications. Each group was dipped for 15 s in 750 ppm PAA or water, and a 90s wait period was used between multiple dips. Samples were stored for 48 h. After the 48-h storage, the tenderloins were subjected to tumbling marination with a vacuum of 21 mm Hg for 5 min and storage for 24 h. pH; color L*, a*, and b*; percentage pickup (postdip); percentage drip loss (after storage); percentage marination pickup; purge percentage cook loss; and percentage cook yield were assessed. Data were subjected to 1-way analysis of variance (P < 0.05). Means were separated using Tukey’s honestly significant difference using P value less than 0.05 for significance.

Results: No difference (P > 0.05) was found among treatments in initial pH, L*, a*, or b*. However, dipping tenderloins in PAA resulted in lower (P < 0.05) pH after premarination storage compared with water, or the NC, and, in addition, PAA5 still resulted in lower pH postmarination storage (P < 0.05) compared with the NC. Dipping treatments and water dipping showed no difference in pH after marination storage. Tenderloins subjected to PAA resulted in higher (P < 0.05) L* after premarination storage compared with the NC. However, PAA1 showed no significant difference (P > 0.05) compared with the water dipping treatment. PAA5 resulted in higher (P < 0.05) values of L*, and PAA3 showed significant differences (P < 0.05) compared with PAA5, PAA1, and the NC, whereas PAA1 showed no significant differences (P > 0.05) compared with water dipping and the NC. The a* values decreased in PAA3 and PAA5 (P < 0.05) after premarination storage. However, PAA5 had the lowest a* value (P < 0.05) after postmarination storage. PAA5 had a higher (P < 0.05) pickup and drip loss after dipping compared with all other treatments. No significant difference (P > 0.05) was found for marination pickup among the treatments. PAA5 had the highest cook loss and the lowest cook yield among the treatments (P < 0.05).

Conclusion: Results indicated that storage time and marination combined with varying PAA dip frequency can decrease the pH, a*, pickup, drip loss, and cook yields. Storage time and marination can increase cook loss and L* on tenderloins dipped in peracetic acid. Storage time and different quantities of peracetic acid dips can impact color and water holding capacity before and after marination, resulting in a direct impact on meat quality.

Funding Source: Novus International Professor.

Keywords: tenderloins, meat quality, storage, water holding, marination.

127 Investigating the Role of Mitochondria in Postmortem Metabolism and pH Decline in Pork

Fatema R. Mishu*, Mohammed A. Alruzzi, Chandler D. Stafford, Madeleine R. Monsivais, Lamis A. Ali, Melinda E. S. Rocha, and Sulaiman K. Matarneh, Department of Nutrition, Dietetics, and Food Sciences, Utah State University, Logan, UT 84322, USA *fatema.mishu@usu.edu

Introduction/Objectives: Mitochondria play a key role in postmortem muscle metabolism, primarily by sequestering calcium in an attempt to maintain cellular calcium homeostasis. Calcium influx into mitochondria is mediated by the mitochondrial calcium uniporter (MCU), a highly selective calcium channel localized to the inner mitochondrial membrane. This process directly influences muscle contraction and adenosine triphosphate consumption, both of which are closely linked to the rate of postmortem metabolism and pH decline. However, the extent to which mitochondrial-mediated regulation of cytosolic calcium affects the rate of postmortem muscle metabolism remains unclear. Therefore, this study aimed to explore how mitochondrial calcium uptake influences postmortem muscle metabolism, particularly examining its impact on the rate of pH decline and key glycolytic metabolite levels in porcine longissimus muscle. We hypothesized that inhibiting mitochondrial calcium uptake with DS16570511, a specific inhibitor of MCU, would elevate cytosolic calcium concentration, thereby accelerating postmortem metabolism and pH decline.

Materials and Methods: Eight market-weight pigs of similar genetic backgrounds were harvested at the Utah State University Animal Harvest Facility. Within 5 min postmortem, the longissimus muscle was excised from one side of each carcass and fabricated into ten 2.5-cm-thick steaks. Steaks were weighed and randomly injected with 1 of 2 treatments: DS16570511 dissolved in saline solution (final concentration, 100 μmol/g of muscle) or saline only (control). One steak from each treatment was cut and snap-frozen immediately (0 min), whereas the remaining steaks were packaged and stored at 4°C for 60, 120, 240, or 1,440 min. At the end of each storage period, steaks were removed from their packages and subsequently processed and stored in the same manner as the 0-min samples. Muscle pH and glycolytic metabolite concentrations were evaluated at all time points, whereas pork color was only evaluated on the 1,440-min samples. Data were analyzed using a mixed model of JMP (SAS Institute Inc., Cary, NC). The statistical model included the main effects of treatment, time, and their interactions and the random effect of the steak. The least-squares means were evaluated using a Student’s t-test and considered significant at P value less than or equal to 0.05.

Results: Steaks injected with DS1657051 had lower pH values at 60, 120, and 240 min than their control counterparts (P ≤ 0.03), whereas no differences were observed at 0 and 1,440 min. As expected, lactate levels increased over time in both groups (P < 0.0001), with the treatment group showing greater values at 120 and 1,440 min (P ≤ 0.05). No differences in glucose-6-phosphate (G6P) were observed between the 2 treatments at 0, 60, 120, and 240 min. However, a significant difference in G6P was observed at 1,440 min, with control steaks exhibiting greater G6P concentration than the treated steaks (P = 0.002). Glucose levels differed between treatments only at 120 min (P = 0.03), when DS1657051-treated steaks possessed more glucose. Analysis of pork color, performed on the 1,440-min samples, showed a lower a* (redness) value in the treated group compared with the control group (P = 0.01), whereas L* (lightness) and b* (yellowness) were not affected.

Conclusion: Inhibiting mitochondrial calcium uptake significantly influenced postmortem muscle metabolism by accelerating pH decline, increasing lactate accumulation, and altering G6P and glucose levels. Additionally, the treatment reduced pork redness, resembling the discoloration characteristic of pale, soft, and exudative pork. These findings highlight the significant role of mitochondria in postmortem metabolism and their impact on pork quality, providing a foundation for developing metabolic interventions to optimize pork quality.

Funding Source: US Department of Agriculture (USDA) National Institute of Food and Agriculture (NIFA).

Keywords: mitochondrial calcium uniporter, postmortem metabolism, pH decline, lactate, pork quality.

128 Effect of Stunning Methods and Deboning Time on Broiler Breast Quality During a 7-Day Retail Display

Zahidul Hasan Tushar*, Rishav Kumar, Matthew Hughes, Matthew Bailey, Shijinaraj Manjankattil, and Dianna Bourassa, Auburn University, Auburn, AL 36849, USA *zzt0028@auburn.edu

Introduction/Objectives: Controlled atmosphere stunning (CAS) of broiler chickens is becoming more popular, but electrical stunning (ES) is still the most common way that commercial poultry facilities process birds. The quality of broiler breast meat is influenced by stunning and deboning time, whereas the joint effect of CAS and deboning time during retail display remains unclear. Consumer appeal while buying meat is influenced by retail displays and lighting within cases, but during retail storage, these lights also intensify light-induced oxidation. The objective of this study was to assess the interaction between the stunning method and deboning time on shelf-life metrics (color stability, lipid oxidation, microbiological growth) and meat quality during a 7-d retail display period.

Materials and Methods: A 2 × 3 factorial design was used, considering 2 different stunning methods (CAS and ES) and 3 deboning times (1 h, 2 h, 4 h) with 60 broilers (42 d of age) allocated, 30 for each stunning method and 10 per deboning time subgroup. The experiment was conducted at the Charles C. Miller Jr. Poultry Research and Education Center at Auburn University. CAS and ES were performed according to established industry standards. For ES, birds were shackled and stunned at 20 mA/bird for 12 s, neck cut, bled, hard scalded, and defeathered. For CAS, birds were stunned in their transport modules by increasing CO₂ concentrations from 20% to 85% over 6 min. Following defeathering, the carcasses continued through evisceration and then ice and water immersion chilled until breast fillets were deboned at 1, 2, or 4 h. The 6 treatment groups included CAS1h, CAS2h, CAS4h, ES1h, ES2h, and ES4h. Half of the breast fillets were weighed, packed in a zip-top bag, and kept in a cooler on ice for evaluation at 24 h. The pH, color (L*, a*, b*, hue, chroma), lipid oxidation (mg malonaldehyde/kg), drip loss (%), shear force (N), and aerobic bacteria levels (log 10 CFU/mL) were measured at 24 h (day 0). The rest of the breast fillets were weighted and then utilized for retail light display (3,000 lux) on Styrofoam trays, covered in polyvinyl chloride film, and stored for 7 d. On day 7, pH, color, lipid oxidation, drip loss, shear force, and aerobic bacteria levels were measured. Data were analyzed using linear mixed-effects models (restricted maximum likelihood estimation with Kenward-Roger adjustments) and Tukey’s honestly significant difference for mean separation using SAS (PROC MIXED) with significance at P value less than 0.05.

Results: Although the stunning technique (CAS vs. ES) had no significant impact on pH (P > 0.05), pH decreased with increasing deboning time (P = 0.035) at day 0 but did not differ at day 7 (P = 0.938). The final carcass temperatures for 1, 2, and 4 h were 7.83°C, 5.88°C, and 4.44°C, respectively. There was no significant difference in drip loss at day 0 or day 7. Drip loss increased with storage (P < 0.001). Deboning time showed a significant increase (P = 0.007) for L* on day 0, with the highest for 4 h (54.26), over 2 h (53.71), and 1 h (51.93). a* was significantly influenced by the deboning time (P < 0.001) and stunning × deboning time interaction (P < 0.001). There was no effect of stunning and deboning time or their interactions on b* on day 0 or day 7. Deboning time showed a significant (P = 0.0004) impact on hue angle on day 0, but stunning did not show any difference. Also, there was no effect on chroma on day 0 or day 7. Oxidation increased from day 0 (0.0079, P < 0.001) to day 7 (0.0187, P < 0.001) and was also influenced (P = 0.039) by the stunning methods on day 0. On day 7, there was also a significant effect (P = 0.037) of the stunning method. CAS birds showed higher (0.02) lipid oxidation than ES (0.01, P = 0.05). However, no significant effects were observed for deboning time and interactions. There was no significant effect of stunning and deboning time on shear force, but shear force significantly increased (P < 0.001) by day 7. Stunning method (P = 0.02) and deboning time significantly (P = 0.004) affected aerobic plate count (APC) on day 0. On day 7, only deboning time showed a significant (P < 0.001) effect. Also, there was a significant (P < 0.001) increase in aerobic plate count as the time of storage increased.

Conclusion: Deboning time affected pH, L*, a*, hue angle, and APC on day 0 but had minimal impact when evaluated after 7 d of storage. Additionally, the CAS method impacted lipid oxidation values on both day 0 and day 7. Storage time showed expected reductions in pH, increases in drip loss, lipid oxidation, shear force, and microbial growth observed by day 7 of retail display. These results emphasize that, although the time of deboning for broiler breast fillets does have immediate quality impacts, those differences are reduced over time. Our observed change in lipid oxidation between stunning methods may warrant further investigation.

Funding Source: This work was supported by the United States Department of Agriculture Agricultural Research Service, Athens, Georgia, project number 6040-42440-001-011-S; the Alabama Agricultural Experiment Station; and the Hatch Program of the National Institute of Food and Agriculture, US Department of Agriculture.

Keywords: chicken, quality, stunning, deboning, retail.

129 Determining the Effect of Electromagnetic-Assisted Freezing on the Thawing Yield and Tenderness of Previously Frozen Beef Longissimus Lumborum

Jordan T. Looper^1,*, Sara R. Hene¹, Sabrina D. Lee¹, Zebang Zhou², Bret N. Flanders³, Travis G. O’Quinn¹, Morgan D. Zumbaugh¹, and Michael D. Chao¹, ¹Department of Animal Sciences and Industry, Kansas State University, Manhattan, KS 66506, USA, ²Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN 47907, USA, ³Department of Physics, Kansas State University, Manhattan, KS 66506, USA *jtlooper@ksu.edu

Introduction/Objectives: Large and irregularly shaped ice crystals have been shown to increase mechanical damage to muscle fibers during freezing, resulting in negative quality attributes, such as increased purge loss and changes in tenderness. Therefore, novel approaches, such as the incorporation of electromagnetic field (EM) to reduce ice crystal outgrowth during freezing of beef, have been studied. EM freezing has been theorized and shown to produce smaller, rounder ice crystals that are more evenly distributed, resulting in thawed beef more closely resembling fresh, never-frozen products. However, many of these studies focus on smaller cuts of beef compared with whole subprimals. The objective of this study was to determine the effect of EM-assisted freezing on the ice crystal size, thawing yield, and tenderness attributes of previously frozen beef longissimus lumborum (LL).

Materials and Methods: LL were collected from both sides of 12 US Department of Agriculture Choice carcasses, and each LL was halved into 2 equal parts and weighed. These halves were randomly assigned to 0, 2, 4, or 8 kV of EM and frozen under the designated treatments in a walk-in freezer (−20°C) for 24 h. Frozen cores were taken for x-ray–computed tomography for ice crystal size analysis. Weights were taken before and after coring to account for the weight of the cores. Following the freezing treatment, LL halves were thawed for 72 h at 2°C, weighed to measure total thaw yield, fabricated into steaks, and subjected to 10-d simulated display. Histological analysis for muscle fiber spacing was measured on steaks with 0-d display. Warner-Bratzler shear force (WBSF) was performed on steaks from days 0 and 10. Finally, protein degradation and free calcium analysis were conducted on steaks displayed for 0, 4, 7, and 10 d.

Results: Total thaw yield was highest for the LL halves from the 8-kV treatment compared with those from the other treatments (P < 0.01). However, no main effect of EM treatment was observed for muscle fiber spacing or ice crystal diameter (P > 0.05). On the other hand, degraded troponin-T and desmin percentages were lower in the high-voltage treatments compared with those from the 2 kV and the control (P < 0.01), but free calcium concentration was higher in the steaks from any of the EM treatments compared with those from the control (P < 0.01). Although differences in proteolysis were observed among the EM treatments, no main effect of treatment was observed in WBSF. As expected, both troponin-T and desmin degradation increased as display day increased (P < 0.01), and free calcium followed a similar pattern (P < 0.01). WBSF was lower on day 10 than on day 0 (P = 0.01).

Conclusion: Based on our findings, it is possible that EM-assisted freezing disrupted the membranes of calcium-storage organelles while simultaneously inactivating specific proteases. However, EM-assisted freezing shows potential to increase total thawing yield, providing economic incentives for producers on an industry level without altering consumer acceptability in tenderness. Further research should be conducted to determine the feasibility of commercial-scale integration of EM-assisted freezing of beef products.

Funding Source: Research was coordinated by the National Cattlemen’s Beef Association, a contractor to the Beef Checkoff.

Keywords: electromagnetic field, freezing, striploin, XRCT, tenderness.

130 Shipping Factors Affecting Meat Quality Attributes and Meat E-Commerce

Paul Olaoluwaniyi Dahunsi^1,*, Ximena Osorio², Alan R. Vazquez², and Derico Setyabrata^1,3, ¹Department of Animal Science, University of Arkansas, Fayetteville, AR 72704, USA, ²Department of Industrial Engineering, School of Engineering and Sciences, Tecnológico de Monterrey, 64700 Monterrey, Mexico, ³Department of Animal Science, Division of Agriculture, University of Arkansas System, Fayetteville, AR 72701, USA *pdahunsi@uark.edu

Introduction/Objectives: Online grocery shopping has continued to grow since its surge during the COVID-19 pandemic, creating more opportunities for local meat producers to generate profits through direct sales to consumers. Nonetheless, ensuring meat quality throughout shipping requires robust cold chain management, leading to higher shipping expenses that frequently discourage consumers from proceeding with their purchases. Shipping costs depend on a range of factors, which can also affect meat quality differently. The objective of this study was to identify the effects of 6 shipping factors on various meat quality traits.

Materials and Methods: A total of 5 boneless striploins (M. longissimus lumborum, US Department of Agriculture High Choice) were purchased from a local purveyor, aged to 28 d postmortem, and cut into steaks (∼2.54 cm thick and ∼250 g). Steaks were randomly assigned to 32 different shipping treatments, representing combinations of 6 two-level factors: (1) shipping container type (SCT; polystyrene foam vs. green/biodegradable foam), (2) coolant type (CT; ice packs vs. dry ice), (3) ambient temperature (AT; hot vs. cold), (4) shipping duration (SD; 1 d vs. 3 d), (5) Coolant load (CL; 20% vs. 40%), and (6) filler usage (FU; filler vs. no filler). The experiment was designed using a D-optimal approach in JMP Pro v16 to efficiently estimate all main effects and 15 two-way interactions while minimizing the number of experimental units. Each steak was vacuum packaged, frozen at –20°C, and subjected to its assigned simulated shipping condition. Product temperature during shipping was recorded using Thermo Button sensors. The experiment was repeated 3 times. Upon completion of the shipping simulations, samples were stored overnight in a refrigerator prior to analysis. Two steaks per treatment per run were evaluated for quality traits: 1 for odor, instrumental color parameters (L*, a*, b* chroma, and hue angle; following 1 h of blooming), cook loss, and Warner-Bratzler shear force; the other for aerobic bacteria concentration (APC), lactic acid bacteria concentration (LAB), thiobarbituric acid reactive substances assay, and pH. Data were analyzed using a linear mixed-effects model with carcass and experiment run as a random effect and shipping factors (main and 2-way interactions) as fixed effects. Significance was declared at P value less than 0.05.

Results: The results of the current study indicated that the observed factors have different impacts on final product quality following simulated shipping. Among the various factors, FU had the most significant effect on meat quality attributes, including a*, b*, chroma, pH, odor, and LAB (P < 0.05). AT influenced a*, chroma, hue angle, and LAB (P < 0.05). A significant SD impact was observed on WBSF and APC, whereas CL only affected the final meat pH (P < 0.05). No significant effect was observed from SCT and CT on any of the measured attributes (P > 0.05). It could be speculated that the changes in product temperature greatly influenced the final meat quality and contributed to the observed result. The average peak internal temperature of meat shipped in cold AT and hot AT was −0.6°C and 2.1°C, respectively. Although significant differences were observed among treatments following shipping under various conditions, the numerical differences between them were relatively small and potentially not practically meaningful. This suggests that certain shipping practices could potentially be modified to reduce costs without substantially compromising meat quality.

Conclusion: According to the result, shipping factors influenced the final quality attributes of shipped meat differently. The ambient shipping temperature, filler usage, and shipping duration had the greatest impact on the final meat quality in this study. However, only minimal numerical differences were observed between treatments, suggesting that modification of the shipping conditions will not negatively impact the final product quality. Further studies are recommended to enhance the understanding of these factors and their interactions and to create a prediction model for the ideal shipping conditions that optimize meat quality.

Funding Source: This project is funded by the Arkansas Beef Council.

Keywords: beef quality, e-commerce, shipping, palatability, D-optimal.

131 Within-Carcass Relationships of Muscle, Fat, and Bone in the Round, Loin, Rib, and Chuck

Esteban Penados*, Andres Mendizabal, Dale Woerner, Blake Forarker Animal and Food Sciences, Texas Tech University, Lubbock, TX 79409, USA *espenado@ttu.edu

Introduction/Objectives: Carcass composition is often estimated using indicators at singular locations on a carcass, which may oversimplify differential patterns of tissue deposition. Hence, tools developed to more accurately predict carcass composition may need to account for these differential patterns of tissue deposition. Computed tomography (CT) has demonstrated a high degree of efficacy and accuracy in measuring carcass tissue abundance (Foraker et al., unpublished, 2024). The objective of this study was to evaluate relationships between tissue abundance measured by CT in 4 carcass primals: round, loin, rib, and chuck.

Materials and Methods: Cattle (N = 92), including cows (n = 26), steers (n = 39), and heifers (n = 27), were harvested at Washington State University (WSU) Meat Laboratory. Carcasses were chilled a minimum of 28 h, fabricated into 9 pieces at standard industry breaks to reduce the size required to enter the gantry of the CT scanner, and scanned using CT (Aquilion 16, Toshiba Medical Systems, Tokyo, Japan) at the WSU Veterinary Teaching Hospital. Voxels from CT scans were segmented into muscle, fat, and bone and quantified using parameters reported by Foraker et al. (unpublished, 2024). Mass of muscle, fat, and bone determined by CT was computed and expressed as a percentage of the cold side weight within each primal (round, loin, rib, and chuck). Also, ratios of muscle to fat and muscle to bone were calculated within each primal. Pearson correlation coefficients were used to build a matrix and evaluate the relationship between tissue abundance in each primal. We used the software RStudio to generate it.

Results: Within the correlation matrix, we identified that, within muscle tissue, rib and loin were most highly related (r > 0.829), and the lowest correlation was loin with chuck (r > 0.685). Within the bone correlation matrix, we identified that the relationship with the highest correlation was rib and chuck (r = 0.921), and the lowest was round and loin (r = 0.759). Within fat tissue, the correlations with the highest coefficient were rib and chuck (r > 0.967) and rib with loin (r > 0.971). However, the relationship with the lowest correlation coefficient was round and chuck (r = 0.882). Muscle-to-fat ratios were more highly correlated with each other between primals than were muscle-to-bone ratios, indicating that there was more variance among carcass regions in muscle-to-bone ratios. The muscle-to-fat ratio of chuck and loin had the highest correlation (r = 0.96), whereas the correlation between rib with round and loin with round was the lowest (r < 0.91).Within the muscle-to-bone correlation matrix, we identified that the relationship with the highest correlation was chuck and rib and the lowest correlation was loin with rib (r = 0.58).

Conclusion: Anatomically proximate primals exhibited a stronger correlation of tissue abundance than those that were further distant. Muscle-to-bone correlation matrix shows the low relationship that exists between the tissue proportions between rib and loin. This information shows the importance of having different measurement zones in strategic points of the carcass. This work provides an understanding of the differential deposition of carcass tissues among different carcass regions, which may be beneficial in determining a more accurate solution to predicting beef carcass yield.

Keywords: CT, cattle, relationships, tissues, measurement.

132 Effects of Feeding a Multipolyphenol Supplement to Finishing Pigs on Quality and Color Stability of Loin Chops

Diana M. Hernandez¹*, Anna C. Dilger¹, Bailey N. Harsh¹, Ashley Wagner², and Chad A. Stahl³, ¹Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA, ²Probiotech International Inc, Saint-Hyacinthe, QC J2S 8L2, Canada, ³Hypor USA, Beresford, SD 57004, USA *hergo898@illinois.edu

Introduction/Objectives: Vitamin E is commonly added to finishing pig diets for its antioxidant role in protecting muscle tissue from oxidative damage—an issue heightened by increased use of distillers dried grains with solubles, which are high in polyunsaturated fatty acids that are more prone to lipid oxidation. This oxidative process can lead to off-flavors, discoloration, shorter shelf life, and ultimately, reduced consumer acceptance. Although effective, vitamin E’s action is mostly limited to the cell membranes. To enhance antioxidant protection, there has been growing interest in natural polyphenol compounds that act more broadly both within and outside cells. These compounds scavenge free radicals, regenerate vitamin E, and inhibit pro-oxidative processes, which may ultimately enhance the overall effectiveness of vitamin E, improve pork quality, and extend color shelf life. This study aimed to evaluate the effect of supplementing finishing pigs with a multipolyphenol compound (Boreox 50 [BOR]) on quality and shelf life of pork loin chops.

Materials and Methods: Eighty vacuum-packaged pork loins (40 loins per treatment) were received at the University of Illinois, labeled with color-coded tags to anonymize researchers to treatments. Loins were sourced from commercial finishing pigs fed 1 of 2 diets for 90-d preslaughter: an experimental diet containing 10 IU/lb of vitamin E and 3.21 lb/ton of BOR (a polyphenol supplement) or a control diet containing 10 IU/lb of vitamin E without the supplement (CON). Loins were aged at 4°C till 14 d postmortem. After aging, purge loss and ultimate pH were measured. Loins were fabricated into two 2.5-cm chops: 1 for Warner-Bratzler shear force (WBSF) and 1 for retail display. Subjective color, marbling, and firmness were evaluated on the WBSF chop after a 20-min bloom. Instrumental color (CIE L*, a*, b*) was recorded using a Minolta CR-400 Chroma meter (illuminant D65). WBSF chops were vacuum sealed and frozen at −20°C until analysis. For WBSF, chops were thawed at 4°C for at least 24 h and cooked to 63°C on Farberware open-hearth grill. Chops were weighed before and after cooking to measure cook loss percentage. Chops were cored parallel to muscle fibers and sheared perpendicular, using the average of 4 cores per chop to estimate shear force using a Texture Analyzer TA. Retail display chops were placed on foam trays, overwrapped with oxygen-permeable film, and stored at 4°C under continuous lighting for 7 d. Chops were randomly placed and rotated daily. Discoloration was evaluated daily by 6 trained technicians using a 10-cm unstructured scale (anchored at 0%, 50%, 100%). Instrumental color and spectral data were collected daily using a HunterLab MiniScan EZ spectrophotometer (illuminant D65, 10° observer angle, 31.8-mm view area), and reflectance ratios at 630/580 nm were calculated. Data were analyzed using the MIXED procedure of SAS (SAS Inst. Inc., Cary, NC) under a completely randomized design, with fixed effect of diet. Repeated-measures analysis was performed on shelf-life data using a compound symmetry covariance structure. Least-squares means were sliced by day and separated using PDIFF option for shelf-life data. Differences were considered significant at P value less than 0.05.

Results: No differences were observed among the diet groups in loin pH, purge loss, subjective color, yellowness (b*), tenderness (WBSF), or cook loss (P ≥ 0.19). CON chops exhibited greater subjective marbling and firmness scores compared with those fed the BOR diet (P < 0.01). There was a tendency (P < 0.06) for BOR chops to be darker (L*) and redder (a*) than CON chops after aging (day-14 postmortem). Although instrumental lightness (L*) changed over time (P < 0.01), no difference between treatments or interaction between treatment and day of display was observed (P ≥ 0.31). Across all days of retail display, BOR chops were redder (a*) than CON chops (P < 0.01). An interaction between treatment and day of display was also observed for redness, with a greater decrease in redness of CON chops observed at day 6 and day 7 than the previous 5 d of display. Similarly, differences in yellowness (b*) were observed across all days of display (P < 0.01), with CON chops observed as less yellow than BOR chops. However, no interaction between treatment and day of display was observed for yellowness. For visual discoloration, an interaction between treatment and day of display was observed (P < 0.01). However, when sliced by day of display, no differences in discoloration between CON and BOR chops were observed from day 1 to day 5 (P > 0.05). On both day 6 and day 7, CON chops exhibited greater discoloration than BOR chops (P < 0.01). Although the 630/580-nm reflectance ratio decreased over time in both treatments (P < 0.01), BOR chops consistently exhibited greater ratios than those from the CON group (P < 0.01), indicating less surface metmyoglobin accumulation. An interaction between treatment and day of display was also observed (P < 0.01), with reflectance ratios of CON chops declining at a greater rate at day 6 and day 7 than observed the previous 5 d of display.

Conclusion: BOR improved pork color stability during retail display, as evidenced by reduced surface discoloration, greater redness and yellowness, and elevated 630/580-nm reflectance ratios, indicating reduced metmyoglobin accumulation and, consequently, extended shelf life. Importantly, BOR supplementation did not negatively impact key pork quality traits, such as ultimate pH, purge loss, subjective color, tenderness (WBSF), or cook loss. Although slight reductions in subjective marbling and firmness scores were observed, these findings warrant further investigation. Overall, these results suggests that BOR may serve as a promising dietary strategy for commercial pork production systems. This is particularly relevant in retail settings, where improved color stability offers a clear advantage, as meat color is a primary visual indicator of freshness and a major factor influencing consumer purchasing decisions.

Funding Source: Probiotech International Inc.

Keywords: pork, polyphenol, vitamin E, color stability, discoloration.

133 The Effect of Silvopasture Versus Indoor Environment and Broiler Breed on Meat Quality

Jean C. Caceres*, Camila Hammel Sobreira, Afsana Rahaman Munmun, Christina S. Sigmon, Athena D. He-DeMontaron, Allison N. Pullin, Jesse Grimes, Lin L. Walker, and Yan L. Campbell, Prestage Department of Poultry Science, North Carolina State University, Raleigh, NC 27695, USA *jccacere@ncsu.edu

Introduction/Objectives: Outdoor access in broiler production systems is perceived as more natural, environmental, and animal welfare friendly from the consumer’s point of view. In addition to that, several researchers have suggested that outdoor access may influence other meat quality traits, such as fat content, meat color, oxidative stability, sensory attributes, and others. Silvopasture (SP) systems, which combine the use of mature trees and pasture in an open-access environment, may improve broiler meat characteristics compared with conventional (CV) indoor systems. This study evaluated the impact of SP versus CV housing systems and 2 breeds, Ross 708 (fast growing) and SASSO (slow growing), on nutrient composition, pH, color, texture, and the following myopathies: woody breast (WB), white striping (WS), and spaghetti meat (SM). Understanding these factors is essential for improving product quality and sustainability in poultry production.

Materials and Methods: Five hundred birds from each breed were randomly placed into either SP or CV housing systems with 5 pens per system (50 birds/pen). Ross 708 birds were processed at 6 wk, whereas SASSO birds were processed at 8 wk to align with breed-specific growth rates. Measurements included weight for live bird, hot carcass, and cut-up, followed by measurements on the right breast for pH (15 min, 2 h, 24 h, and 3 mo) with a portable pH meter; texture with Warner-Bratzler and BMORS methods using a texture analyzer; myopathy scoring by visual and palpation assessments; and meat composition (fat, moisture, protein, collagen, and ash content), this using near-infrared spectrophotometer meat analyzer. These were analyzed to assess nutritional and structural properties. Measurements were taken on the right breast and thigh for color (24 h and 3 mo). Statistical analysis was conducted using 2-way analysis of variance and general linear model in a 2 × 2 factorial design in SAS 9.4 with Duncan’s multiple-range test for mean separation.

Results: Production systems and breeds significantly impact meat composition and quality attributes. SP birds exhibited lower body weights than CV birds (i.e., live weight: SP = 2.70 kg vs. CV = 2.84 kg, P < 0.05). SASSO birds weighed less than Ross 708 in both systems (i.e., live weight: Ross 708 = 3.21 kg vs. SASSO = 2.34 kg, P < 0.05). For pH, the analysis showed SP birds had a lower pH within 24 h of processing (SP = 5.94 vs. CV = 6.00, P < 0.05). For breeds, Ross 708 meat consistently had greater pH values at all measured intervals. The interaction of SP and SASSO resulted in the lowest pH values at the initial measurement (5.90 at 15 min) and the last (5.92 at 3 mo). In contrast to the other interactions, SP and SASSO were 6.35% lower at 15 min and approximately 2% lower at 3 mo, highlighting breed-specific responses to production systems. Composition analysis revealed that SP meat was not different in fat (2.09% vs. 2.14%), protein content (22.18% vs. 21.95%), and moisture levels from CV meat (P > 0.05). SASSO meat had greater fat content (2.40% vs. 1.83%) and protein content (22.75% vs. 21.39%) compared with Ross 708 meat, regardless of housing system (P < 0.05). Ross 708 meat had a higher moisture level (75.93% vs. 73.67%) than SASSO meat, despite housing system (P < 0.05). Interaction data indicated that SP SASSO meat had the greatest fat (2.70%) and protein content (22.44%) (P < 0.05). Myopathy scoring indicated that Ross 708 breasts had a greater incidence of WB and WS and mild SM (P < 0.05), whereas SASSO meat showed minimal WS and no WB or SM. SP meat demonstrated a lighter thigh color than CV meat, and SASSO breasts were darker, redder, and less yellow than Ross 708 (P < 0.05).

Conclusion: Both the production system and breed significantly influenced broiler meat quality traits, with differences being more pronounced. SASSO birds, particularly when raised in SP systems, exhibited an enhanced meat quality, with minimal myopathies, greater protein content, and favorable pH stability. However, these benefits may reflect a better compatibility of SASSO with the SP environment rather than a universal advantage of SP systems. In contrast, Ross 708, especially under SP conditions, demonstrated a higher incidence of myopathies, lower protein content, and less-stable postmortem pH values. These results suggest that the SP system may enhance product quality and consumer acceptance while reducing product defects and economic losses, considering the genetic factor of each breed. Future studies should expand on evaluating additional meat attributes, such as oxidation ratio (thiobarbituric acid reactive substances assay), sensory quality, and fatty acid profile, further to define SP’s potential advantages and limitations in sustainable broiler meat production across different genetic lines.

Funding Source: Founding: General Mills.

Keywords: rearing, breed, welfare, meat quality.

134 Association of Cattle Type and Liver Abscesses Upon Retail Color of Beef Striploin Steaks

Megan E. Eckhardt*, Trent E. Schwartz, Loni W. Lucherk, and Ty E. Lawrence, West Texas A&M University, Canyon, TX 79016, USA *meckhardt@wtamu.edu

Introduction/Objectives: Muscle color changes from oxymyoglobin to metmyoglobin during retail display are well documented. Intrinsic factors, including breed and health, as well as extrinsic factors, including postmortem handling, are known to impact biochemical changes of meat products. Variability of muscle composition and metabolism traits via fiber type proportions amongst breeds of cattle suggests additional implications on retail color performance. Currently undocumented in literature are the confounding associations of cattle type and liver abscess pathology upon retail color life. Thus, the objectives of this study were to determine the associative effects of native versus dairy genetics and liver abscess occurrence upon objective color stability of beef longissimus lumborum steaks in a simulated retail setting.

Materials and Methods: A completely randomized experimental design utilizing a 2 × 2 categorical treatment structure consisting of cattle genetic type (CATTLE; NAT, native; DX, dairy-cross) and liver abscess occurrence (LIVER; EDIBLE, edible liver; ABSCESS, major liver abscess [A+, Elanco scoring system]) was used to develop 4 categorical combinations. Striploins (n = 44; 11 per cattle type and liver abscess category) were collected at a commercial beef abattoir, and the 3 most anterior 1.3-cm-thick steaks (n = 132 total steaks) were cut, vacuum packaged, and stored in the absence of light at 3°C for 7, 21, or 35 d until retail display. Steaks were displayed for a 228-h duration at 2°C to 4°C in a multideck retail case and rotated daily. Instrumental color (L*, a*, b*, spectral values) were collected at 0 h and every 12 h until 228 h. Hue angle and chroma saturation values were calculated via a* and b* values. Percentage deoxymyoglobin (DMb), oxymyoglobin (OMb), and metmyoglobin (MMb) were calculated using spectral values (470, 480, 520, 530, 570, 580, 610, and 700 nm). Data were analyzed using mixed models; cattle type and liver abscess occurrence were fixed effects, and marbling was a covariate to control for lean area variance. Although previously established as contributing fixed effects, aging duration and hour of display were considered random effects to improve the clarity of results responding to the current study objectives. Feedlot of origin and steak number were also considered random effects. Data were analyzed as repeated measures using the compound symmetry covariance structure.

Results: Numerous steak objective color measurements were affected (P ≤ 0.015) by the interaction of CATTLE × LIVER or the LIVER main effect (P ≤ 0.005). Lightness (L*) was impacted by the CATTLE × LIVER interaction (P < 0.001). Within DX, EDIBLE was lighter than ABSCESS, and, alternatively, the opposite was observed within NATIVE (P ≤ 0.005). Each treatment combination differed (P ≤ 0.005) from one another (DX-EDIBLE > NAT-ABSCESS > NAT-EDIBLE > DX-ABSCESS). The DX-EDIBLE steaks presented the lightest color, whereas the DX-ABSCESS steaks had the darkest lean color. Redness (a*) interaction means differed (P = 0.015); DX-ABSCESS steaks were redder (P ≤ 0.002) than both DX- and NAT-EDIBLE steaks. The NAT-ABSCESS steaks were also redder (P = 0.017) than DX-EDIBLE steaks, although both CATTLE-EDIBLE steaks (P = 0.197) were similar in redness. Complementary to redness, the CATTLE × LIVER interaction (P = 0.005) for hue angle suggested DX-EDIBLE steaks had the largest hue angle (P = 0.015), indicative of the least-red color. All other steaks were similar (P ≥ 0.171). The data suggest DX steaks provide the widest range of red color, indicated by the largest and smallest numerical hue angle and a* values. Chroma saturation was impacted by LIVER (P = 0.001), in which steaks from cattle with a severe liver abscess were more saturated in color. Both percentage of MMb and DMb were impacted by the CATTLE × LIVER interaction (P ≤ 0.001). Indicative of discoloration, NAT-ABSCESS and DX-EDIBLE steaks were similar (P = 0.669) and higher (P = 0.011) for percentage MMb than NAT-EDIBLE, whereas DX-ABSCESS steaks were intermediate (P ≥ 0.226). Lastly, oxymyoglobin percentages were impacted by LIVER (P = 0.005), in which OMb percentages were higher for steaks from cattle containing a liver abscess than from cattle with edible livers.

Conclusion: Steak color attributes were significantly influenced by cattle type and liver abscess occurrence, with notable interactions. Steaks from DX-EDIBLE cattle were lightest and least red in color, whereas DX-ABSCESS steaks were darkest and reddest. Liver abscesses were associated with increased color saturation and oxymyoglobin content of steaks. Steaks from DX cattle exhibited the widest range of color variation, suggesting that both liver health and cattle type are factors in determining beef color quality. Altered liver function and diminished glycogen production and storage likely result from severe liver abscesses. Alteration of muscle metabolism resulting from liver abscesses possibly promotes a darker, more concentrated red color, as witnessed in the current study. This pathology may differ in impact due to cattle genetic types. These findings suggest that liver abscess status, in combination with cattle type, plays a role in beef color at retail.

Funding Source: This project was funded by the West Texas A&M University Beef Carcass Research Center.

Keywords: beef, display, myoglobin.

135 The Influence of Cold Storage Practices on Meat Quality Attributes of American Ground Lamb

Kiersten Gundersen¹*, Amy Volk¹, Wanda Keller¹, Mara Hitchert¹, Erin Beyer², Kasey Maddock-Carlin¹, Travis Hoffman¹, ¹Animal Sciences, North Dakota State University, Fargo, ND 58105, USA, ²Animal Sciences, Kansas State University, Manhattan, KS 66506, USA *kiersten.gundersen@ndsu.edu

Introduction/Objectives: American lamb seasonality of supply and preference for fresh retail product inherently challenges the cold supply chain management from processor to consumer. Cold storage practices can significantly impact inventory, lamb quality, and consumer satisfaction. Both fresh and frozen lamb storage results in less-than-ideal outcomes on color stability and product oxidation, resulting in economic losses and reduced consumer appeal. The objective of this study was to determine whether an alternative cold storage method is a viable option to conventional fresh and frozen ground lamb storage. The supply chain may encourage fresh American lamb at retail, yet we further evaluated a modified fresh and frozen ground lamb product for changes in color, oxidation, and cook loss.

Materials and Methods: Ground lamb packages (1.0 lb; N = 60) were singly sourced from a US lamb processing facility and equally divided into 3 categories: fresh (F), frozen (FZ), and modified fresh technology (MF). MF is a patented, proprietary, and trademarked process that stores red meat protein near freezing while maintaining a fresh status. For this study, ground lamb packages designated to FZ or MF were stored for 36 d prior to evaluation; fresh was 2 d prior to evaluation. Patties were formed using a commercially available patty maker to 113 g. Patties from each treatment group were assigned to (1) 5-d shelf life, (2) pH and cook loss, (3) lipid oxidation analysis (stored at −80°C), and (4) proximate analysis (sent to Kansas State University). Patties were equilibrated to room temperature prior to cooking, and raw weight was collected. Patties were cooked on an electric clam-shell grill (Cuisinart Electric Griddler GR5DP1, Cuisinart, Stamford, CT). The internal temperature of the patties was monitored with a Thermapen (ThermoWorks THS-235-427, American Fork, UT) placed in the center of each patty until a peak internal temperature of 71°C was reached. All patties were allowed to cool for a minimum of 10 min before cooked patties were weighed and cook loss percentage was calculated. For 5-d shelf life, patties were packaged on a Styrofoam tray, overwrapped in polyvinyl chloride film, and displayed in a 4°C cooler under continuous fluorescent lighting. Color measurements were taken every 24 h with a Minolta colorimeter (CR-450 Chromameter, Konica Minolta, Tokyo, Japan). A portable pH meter HI 99163 (Hanna Instruments, Woonsocket, RI) was used to collect intramuscular pH values. Lipid oxidation was assessed utilizing OxiSelect thiobarbituric acid reactive substances assay kit (malondialdehyde [MDA] quantification; Cell BioLabs, Inc. San Diego, CA) by following the manufacturer’s procedures with modifications as follows: Samples were incubated in dry heating blocks at 100°C for 45 min, cooled, and centrifuged at 10,000 × g at 12°C for 12 min. All data were analyzed with PROC GLIMMIX procedure of SAS 9.4 to identify differences across fixed effects (treatment group and retail display day). Significance was determined at P value less than or equal to 0.05.

Results: There was a treatment effect (P ≤ 0.05) on pH in which F was lower than MF, and that was lower than FZ. A tendency (P ≤ 0.10) of treatment effects was observed for cook loss wherein MF was lower than FZ. There were differences (P ≤ 0.05) for treatment and treatment × retail display day for L*, a*, and b* values. F had the most preferred color stability, with higher L* values across the 5-d retail display. MF was lighter than FZ from day 2 to day 4. F was less red (a*) than MF, and MF was less red than FZ from day 1 until the completion of the retail display. There was a treatment effect (P ≤ 0.05) on mg of MDA/kg of meat levels, with F having the highest MDA levels. Treatment F had noticeably more mg of MDA/kg of meat levels (13.34 mg of MDA/kg of meat) compared with FZ (11.05 mg of MDA/kg of meat) and MF (10.70 mg of MDA/kg of meat). F had the highest (P ≤ 0.05) percentage of fat and the lowest (P ≤ 0.05) percentage of moisture compared with both FZ and MF. Protein was not (P ≥ 0.05) different across treatments. The higher fat percentages in the F could contribute to the lighter L* values measured as well as the higher MDA levels because of increased susceptibility to oxidation. The higher MDA levels in F could be a factor in the lower a* values compared with FZ.

Conclusion: The primary takeaways from this study are: (1) MF had a reduced cooking loss compared with FZ treatment, and (2) the evaluations for color stability that influence discoloration rates find MF and F treatments similar in comparison. Therefore, our analysis provides insights into alternative storage options for fresh ground lamb in that retail display color and oxidation of MF samples were within the range of measurements observed from F and FZ samples, with additional improvements on cook loss percentage. Therefore, MF is a viable storage option that could help improve American lamb supply availability and end-product quality management.

Funding Source: American Lamb Board.

Keywords: American lamb and meat quality.

136 Evaluating the Effects of Storage Conditions and Packaging Methods on the Shelf Life and Quality Attributes of Sturgeon Fillets (Acipenser spp.)

Logan Rosenberg, Toni Duarte, Yuyuan Feng, Saiful Islam, Sudipta Talukder, Jackson A. Gross, and Xiang Yang, University of California, Davis, Davis, CA *larosenberg@ucdavis.edu

Introduction/Objectives: California accounts for much of the sales revenue from sturgeon products in the United States. Although caviar remains the premium and most recognized product, sturgeon meat is becoming increasingly valued for its culinary versatility and appeal to health-conscious consumers for its high protein and beneficial fat content. As the market grows, understanding spoilage dynamics is becoming increasingly crucial for ensuring product quality and safety across distribution. This study evaluated the effects of storage and packaging methods on the meat quality of sturgeon fillets at retail display.

Materials and Methods: Male white sturgeons (N = 32, everage weight = 15.69 kg) were harvested using percussion stunning and gill and tail bleeding from a commercial farm in California. Fish were randomly assigned into 1 of 4 dark storage treatments: chilled for 3 d (C3), chilled for 7 d (C7), frozen for 1 mo (FZ), and blast frozen followed by frozen for 1 mo (BT). At the end of dark storage, within each fish, 2 fillets were packaged individually in polystyrene trays and overwrapped (OW), and another 2 fillets from the same fish were vacuum packaged (Vac). Packaged samples were placed on a commercial display case (1°C) and exposed to light for 5 d. Microbial counts (log CFU), lipid oxidation (mg malondialdehyde/kg meat), texture (texture profile analysis), color, pH, and drip loss studies were conducted in order to analyze spoilage indicators on each fillet on day 00 (after slaughter), day 0 (after dark storage), and day 5 (end of retail display). Microbial analysis specifically measured the populations of Enterobacteriaceae (EB), Pseudomonas spp. (PS), lactic acid bacteria (LAB), and aerobic psychrotrophic bacteria (APB). Statistical analyses were conducted in R using linear mixed-effects models appropriate to each experimental design: split-plot designs for microbial, texture, drip loss, and pH data and a split-split plot design for color measurements. Significant main effects and interactions were evaluated using analysis of variance and post hoc pairwise comparisons with an α level of 0.05.

Results: Baseline fillets had no significant differences (P > 0.05) in microbial counts for all bacteria types. After dark storage, microbial counts in frozen groups decreased (P < 0.05) EB and PS. Although FZ samples retained lower (P < 0.05) APB, PS, and LAB, these samples ended with the highest (P < 0.05) EB counts by day 5. Chilled groups had higher (P < 0.05) APB and PS counts regardless of the packaging. Vacuum packaging did not significantly reduce microbial growth. In the few cases when differences were observed, they were less than 1 log CFU/g. Drip loss for all the groups increased (P < 0.05) after dark storage. The FZ groups had the highest (P < 0.05) drip loss (14.8%), whereas BT had similar values with the chilled groups (P > 0.05). Concurrently, the pH of samples decreased (P < 0.05) over time, indicating a reduced water holding capacity contributing to increased drip loss. Texture attributes were uniform for baseline samples (P < 0.05). However, hardness, chewiness, and gumminess would differ (P < 0.05) in C3 and FZ groups. By day 0, frozen groups experienced a significant reduction in hardness, springiness, and chewiness. By day 5, OW-BT would exhibit the highest (P < 0.05) chewiness scores. Frozen groups had higher (P < 0.05) cohesiveness than chilled groups, regardless of packaging type. Vac samples also retained significantly greater springiness (P < 0.05) than overwrapped counterparts. The average initial thiobarbituric acid reactive substances assay (TBARS) values for all samples were similar (0.626; P > 0.05). After dark storage, frozen groups exhibited lower (P < 0.05) TBARS values than chilled groups. By the end of the retail display, C7 groups had the highest (P < 0.05) average TBARS value (0.844) among all the storage groups. Packaging types did not (P > 0.05) affect the TBARS values. Only packaging significantly affected L*. Vac samples retained higher (P < 0.05) L* values, or a lighter appearance, than overwrapped samples across all storage groups. The a* values decreased (P < 0.05) over time, and chilled groups retained higher (P < 0.05) a* values than frozen groups by day 5. Overall, b* values increased (P < 0.05) over time, whereas the storage methods and packaging types had a variable effect (P < 0.05). The Vac-C7 groups maintained the lowest (P < 0.05) b* values over time among all treatment groups. In contrast, OW-C3 and Vac-FZ samples exhibited the highest (P < 0.05) b* values.

Conclusion: The findings of this study suggest that the freezing process initially reduced microbial counts, but this advantage diminished during retail display after the fish were thawed. Additionally, the vacuum packaging method used did not demonstrate a clear advantage in reducing microbial load or slowing lipid oxidation. Regarding the physicochemical and sensory attributes of the fish fillets, BT-Vac fillets retained better color, had lower drip loss, and preserved key textural properties, such as chewiness and adhesiveness. This makes BT-Vac a promising combination for maintaining overall fillet quality during frozen storage and retail display.

Funding Source: Western Regional Aquaculture Center.

Keywords: fish, sturgeon, shelf, quality, spoilage.

137 The Influence of Cold Storage Practices on Meat Quality Attributes From American Retail-Ready Sirloin Lamb Chops

Kiersten Gundersen¹*, Wanda Keller¹, Mara Hirchert¹, Virginia Montgomery¹, Erin Beyer², Kasey Maddock-Carlin¹, Travis Hoffman¹, ¹Animal Sciences, North Dakota State University, Fargo, ND 58105, USA, ²Animal Sciences, Kansas State University, Manhattan, KS 66506, USA *kiersten.gundersen@ndsu.edu

Introduction/Objectives: Supply and demand for fresh retail American lamb is a challenge for retail chains and purveyors reaching consumers. Furthermore, retail chains affirm that lamb is most preferred fresh and not frozen in the meat case. The lamb industry offers retail-ready steaks and chops for convenience. Cold storage practices can play a considerable role in lamb quality and merchandising of products. The objective of this study was to investigate lamb quality attributes and corresponding physiochemical differences between different cold storage practices. Storage can impact color stability, consumer appeal, and economics across the supply chain. With an inconsistency of continuous availability of fresh lamb, storage optimization was evaluated for alternative cold supply chain management with a modified fresh and frozen retail-ready chop.

Materials and Methods: Retail-ready paired lamb sirloin chops (N = 100) were sourced from a US lamb processing facility. The sirloin chops were divided into 5 categories: fresh (F), frozen (FZ), and modified fresh technology (MF) for 60 d, 75 d, and 90 d. MF is a patented, proprietary, and trademarked process that allows for the storage of red meat proteins at temperatures at or slightly above freezing point while maintaining the fresh status. From the packages of each treatment, 1 sirloin chop was assigned to 5-d shelf life and lipid oxidation. An approximate 50-g sample was allocated from the sirloin chop for lipid oxidation and stored at −80°C. The second sirloin chop was used for moisture loss and Warner-Bratzler shear force (WBSF). Sirloin chops were equilibrated to room temperature prior to cooking, and raw weight was collected. Chops were cooked on an electric clam-shell grill (Cuisinart Electric Griddler GR5DP1, Cuisinart, Stamford, CT). The internal temperature of the chops was monitored with a Thermapen (ThermoWorks THS235-427, American Fork, UT) placed in the center of each chop and cooked to a target temperature of 71°C. All chops were allowed to cool for a minimum of 10 min before reweighing and cook loss percentage calculation. For 5-d shelf life, sirloin chops were packaged on a Styrofoam tray, overwrapped in polyvinyl chloride film, and displayed in a 4°C cooler under continuous fluorescent lighting. Color measurements were taken every 24 h with a Minolta colorimeter (CR-450 Chromameter, Konica Minolta, Tokyo, Japan). Lipid oxidation was assessed utilizing OxiSelect thiobarbituric acid reactive substances assay kit (malondialdehyde [MDA] quantification; Cell BioLabs, Inc. San Diego, CA) by following the manufacturer’s procedures modifications as follows: Samples were incubated in dry heating blocks at 100°C for 45 min, cooled, and centrifuged at 10,000 × g at 12°C for 12 min. All data were analyzed with PROC GLIMMIX procedure of SAS 9.4 and used to identify differences across fixed effects (treatment group and retail display day). Mean was considered significant when P value was less than or equal to 0.05.

Results: There was a treatment effect (P ≤ 0.05) on drip loss, cook loss, and WBSF. MF lamb sirloin chops had lower amounts of drip loss, greater cook loss, and improved tenderness compared with F or FZ sirloin chops. MF sirloin chops had lower WBSF values compared with F or FZ sirloin chops, but there were no differences amongst MF 60-d, 75-d, and 90-d WBSF values. There were differences identified (P ≤ 0.05) for treatment × retail display day for L*, a*, and b* values. MF chops, regardless of storage time, had higher L* values compared with F and FZ treatments, appearing visually lighter from day 0 to day 4. The FZ chops had the highest a* values (P ≤ 0.05) throughout the entire retail display, and MF at 60 d had the lowest a* values throughout the entire retail display. There was an effect (P ≤ 0.05) on MDA levels, with F having the highest MDA levels as an indication of lipid oxidation. There were no differences observed between FZ and MF treatments.

Conclusion: The primary takeaways from this study are: (1) MF had noticeable less drip loss than FZ treatment; (2) MF had exhibited greater tenderness, as indicated by lower WBSF values, compared with F and FZ treatments; (3) MF visually appeared lighter in color when evaluating color stability; and (4) MF and FZ had a lower amount of MDA levels than F to indicate less lipid oxidation. As an alternative to fresh lamb, our analysis provides insight into alternative storage options for retail-ready lamb. Acceptable color stability comparisons and lipid oxidation values, along with less drip loss and improved tenderness, reinforce the potential commercial acceptance of MF compared with either F or FZ American lamb. With lamb quality and consumer acceptability in mind, MF is a viable storage option that could help improve American lamb supply availability and end-product quality management.

Funding Source: American Lamb Board.

Keywords: American lamb, meat quality.

138 Reduction of Listeria monocytogenes in Deli Meat Using Enterococcus faecium J19 and Lactobacillus sakei L15

Brayan Montoya-Torres*, Mauricio Martinez-Martinez, Rosa Pagoada, Qingli Hull, and Mindy Brashears, International Center for Food Industry Excellence (ICFIE), Texas Tech University, Lubbock, TX 79415, USA *brayan.d.montoya@ttu.edu

Introduction/Objectives: Listeria monocytogenes is a major foodborne pathogen, especially in ready-to-eat (RTE) meat products. Recent listeriosis outbreaks linked to deli meats underscore the serious health risks it poses to vulnerable populations. Utilizing lactic acid bacteria (LAB) that produce antilisterial bacteriocins and metabolites offers an effective strategy to inhibit and control L. monocytogenes growth, thereby enhancing food safety management. The deli meat outbreaks further emphasize the pressing need for innovative food safety strategies to protect consumers and ensure food safety. LAB are characterized by the production of lactic acid and other antagonistic metabolic end products, including bacteriocins that demonstrated effective inhibition of L. monocytogenes in previous studies. This study aimed to evaluate the antilisterial effectiveness of 2 characterized LAB strains—Enterococcus faecium (J19) and Lactobacillus sakei (L15)—applied to surface-inoculated deli meat (ham) using sprays to control 3 strains of L. monocytogenes during storage in retail display cases at 4.0°C.

Materials and Methods: Three L. monocytogenes strains, stored at –80°C and selected based on the presence of key virulence-associated genes, were reactivated and cultured to a target concentration of approximately 5 log₁₀ CFU/mL to inoculate ham samples (∼75 samples: 3 independent replicates). Two molecularly characterized LAB strains—E. faecium J19 and L. sakei L15, previously classified as Generally Recognized as Safe (GRAS) through antimicrobial resistance profile, adhesion potential, and cytotoxicity to Caco-2 cells by the International Center for Food Industry Excellence with National Center for Biotechnology Information accession number KJ645709—were also reactivated and cultured to a target concentration of approximately 7 log₁₀ CFU/mL for treatment applications. After ham slices were surface-inoculated with the L. monocytogenes cocktail by dipping, treatments were immediately applied by spraying. The treated slices were then individually vacuum packaged. All ham samples that contained sodium diacetate in their commercial formulation were treated as follows: control (L. monocytogenes + sterile de Mann Rogosa Sharpe broth), Tr1 (L. monocytogenes + J19), and Tr2 (L. monocytogenes + L15). Samples were vacuum sealed, stored at 4°C, and analyzed for L. monocytogenes counts on days 1, 3, 7, 14, and 21 using Modified Oxford Agar and the spread plate method. Colonies from duplicate plates were enumerated, converted to CFU/cm², averaged, and log₁₀-transformed. Statistical analysis was conducted in R (v4.3.2) using the base stats package; a 1-way analysis of variance (lm() and anova() functions) assessed treatment effects, and Tukey’s honestly significant difference post hoc test identified significant differences among means (P ≤ 0.05 and P ≤ 0.01).

Results: Figure 1 and Table 1 present L. monocytogenes counts (log₁₀ CFU/cm²) on deli ham slices inoculated with 5 log₁₀ CFU/mL of L. monocytogenes and treated with probiotic cultures J19 or L15 (7 log₁₀ CFU/mL) stored at 4°C for 21 d. On day 1, the control showed 4.27 ± 0.16 log₁₀ CFU/cm², whereas J19 and L15 achieved reductions of 0.69 ± 0.08 and 0.48 ± 0.16 log₁₀, respectively. By day 3, J19 maintained a decrease of 0.65 ± 0.15 log₁₀, with L15 slightly lower at 0.37 ± 0.21 log₁₀. On day 7, J19 reached a 0.96 ± 0.28 log₁₀ (90%) reduction, whereas L15 achieved 0.52 ± 0.05 log₁₀. By day 14, both treatments exhibited greater efficacy, with J19 reducing L. monocytogenes by 2.03 ± 0.36 log₁₀ (99.0%) and L15 by 1.64 ± 0.11 log₁₀ (97.71%). After 21 d, J19 achieved a 3.25 ± 0.33 log₁₀ reduction (99.94%), outperforming L15 at 3.03 ± 0.01 log₁₀ (99.9%). From day 7 onward, the control (sodium diacetate–treated ham) consistently showed higher L. monocytogenes levels than the J19 treatment, with a difference of nearly 1 log. Both probiotic strains significantly reduced pathogen levels over time, with J19 demonstrating superior antilisterial activity. Treatment Tr1 consistently achieved greater reductions at all time points, exhibiting significantly (P < 0.01) lower counts than both the control and Tr2 on days 1, 3, and 7. From day 14 onward, both probiotic treatments significantly surpassed the control (P < 0.001), with no statistical differences between Tr1 and Tr2. These findings underscore the potent antilisterial effect of probiotic treatments, especially Tr1, under simulated refrigerated storage conditions.