National Beef Quality Audit-2022: Transportation, mobility, live cattle, and hide assessments to determine producer-related defects that affect animal welfare and the value of market cows and bulls at processing facilities.

The National Beef Quality Audit (NBQA)-2022 serves as a benchmark of the current market cow and bull sectors of the U.S. beef industry and allows comparison to previous audits as a method of monitoring industry progress. From September 2021 through May 2022, livestock trailers (n = 125), live animals (n = 5,430), and post-slaughter hide-on animals (n = 6,674) were surveyed at 20 commercial beef processing facilities across the U.S. Cattle were transported in a variety of trailer types for an average distance of 490.6 km and a mean transport time of 6.3 h. During transit, cattle averaged 2.3 m2 of trailer space per animal indicating sufficient space was provided according to industry guidelines. Of all trailers surveyed, 55.3% transported cattle from an auction barn to a processing facility. When surveyed, 63.6% of all truck drivers reported to be Beef Quality Assurance certified. The majority (77.0%) of cattle were sound when evaluated for mobility. Mean body condition scores (9-point scale) for beef cows and bulls were 3.8 and 4.4, respectively, whereas mean body condition scores (5-point scale) for dairy cows and bulls were 2.3 and 2.6, respectively. Of the cattle surveyed, 45.1% had no visible live animal defects, and 37.9% had only a single defect. Of defects present in cows, 64.6% were attributed to an udder problem. Full udders were observed in 47.5% of all cows. Nearly all cattle were free of visible abscesses and knots (97.9% and 98.2%, respectively). No horns were observed in 89.4% of all cattle surveyed. Beef cattle were predominantly black-hided (68.9% and 67.4% of cows and bulls, respectively). Holstein was the predominant dairy animal observed and accounted for 85.7% of the cows and 98.0% of the bulls. Only 3.1% of all animals had no form of identification. Findings from the NBQA-2022 show improvements within the industry and identify areas that require continued education and research to improve market cow and bull welfare and beef quality.

Preslaughter factors affecting mobility, blood parameters, bruising, and muscle pH of finished beef cattle in the United States.

Decades of work have focused on reducing fear, stress, and discomfort in cattle during the preslaughter phase by improving and promoting animal handling, transportation, and management processes. Even still, there is limited information about the effects of preslaughter factors on animal welfare and meat quality outcomes in finished cattle in the United States. This study aimed to track individual animals through the slaughter process to identify preslaughter factors associated with key welfare and quality outcomes. A total of 454 cattle from one commercial slaughter facility were studied. Preslaughter factors assessed included distance traveled, truck waiting time, lairage density, lairage duration, and season. Animal characteristics, i.e., body weight, breed, and sex, were also recorded. One trained observer scored the mobility of all cattle using the North American Meat Institute's 1-4 scale (i.e., normal to extremely reluctant to move). Exsanguination blood was collected and analyzed for cortisol, creatine kinase, and lactate. Carcass bruising was scored using a modified version of the National Beef Quality Audit's bruise-scoring methodology (i.e., no bruise, one bruise ≤ the size of a deck of cards, one bruise > than the size of a deck of cards, and multiple bruises). Ultimate muscle pH was measured 32 to 36 h postmortem. Multi-predictor models were selected for each outcome variable using Akaike Information Criterion. Continuous outcome variables were analyzed using linear mixed-effect models and categorical outcome variables with mixed-effect logistic regression models. Longer truck waiting times were associated with increased cortisol (P = 0.04) and lactate (P = 0.02) concentrations. Similarly, increased lairage duration was associated with increased creatine kinase concentrations (P = 0.05) and the odds of cattle being bruised (P = 0.03). Less space allowance per animal in lairage was associated with increased odds of cattle having impaired mobility (P = 0.01). There was a seasonal effect for many of the measured outcomes; the summer season was associated with greater lactate concentrations (P < 0.0001), increased odds of impaired mobility (P < 0.0001), and increased odds of carcass bruising (P = 0.003). The findings of this study indicate that many of the preslaughter factors assessed influence critical welfare and meat quality outcomes of finished beef cattle, warranting future research and consideration.

National Beef Quality Audit-2022 Phase 1: face-to-face and digital interviews.

The National Beef Quality Audit (NBQA) has been conducted regularly since 1991 to assess and benchmark quality in the U.S. beef industry, with the most recent iteration conducted in 2022. The goal of NBQA Phase I is to evaluate what needs to be managed to improve beef quality and demand. Interviews (n = 130) of industry personnel were conducted with the aid of routing software. In total, packers (n = 24), retailers (n = 20), further processors (n = 26), foodservice (n = 18), and allied government agencies and trade organizations (n = 42) were interviewed. Interviews were routed in software based on interviewee involvement in either the fed steer and heifer market cow and bull sectors, or both. Interviews were structured to elicit random responses in the order of determining "must-have" criteria (quality factors that are required to make a purchase), best/worst ranking (of quality factors based on importance), how interviewees defined quality terms, a strength, weakness, opportunities, threats (SWOT) analysis, general beef industry questions, and sustainability goals (the latter four being open-ended). Quality factors were 1) visual characteristics, 2) cattle genetics, 3) food safety, 4) eating satisfaction, 5) animal well-being, 6) weight and size, and 7) lean, fat, and bone. Best/worst analysis revealed that "food safety" was the most (P < 0.05) important factor in beef purchasing decisions for all market sectors and frequently was described as "everything" and "a way of business." Culture surrounding food safety changed compared to previous NBQAs with interviewees no longer considering food safety as a purchasing criterion, but rather as a market expectation. The SWOT analysis indicated that "eating quality of U.S. beef" was the greatest strength, and cited that educating both consumers and producers on beef production would benefit the industry. Irrespective of whether companies' products were fed or market cow/bull beef, respondents said that they believed "environmental concerns" were among the major threats to the industry. Perceived image of the beef industry in the market sectors has improved since NBQA-2016 for both fed cattle and market cow/bull beef.

Benchmarking the United States bison meat industry: stakeholder perceptions, production parameters, and live animal factors affecting meat quality.

The objectives of this study were 1) to understand stakeholder perceptions regarding the bison industry, 2) to benchmark live animal characteristics and production parameters of the bison industry, and 3) to identify live animal factors related to animal welfare and their effect on specific quality characteristics of bison meat. A survey was conducted both online and in-person at the National Bison Association Winter Conference (2022). Descriptive statistics were performed on a total of 110 surveys. Most stakeholders (94%, n = 104) agreed that the industry should continue to grow, and the majority (99%, 108) agreed that animal welfare impacts meat quality. Facility design (80%, n = 88), animal handling (78%, 86), employee training (56%, 62), and transportation duration (56%, 62) were selected as the factors that affect animal welfare. More than half of the stakeholders selected flavor (67%, n = 74) as the most important quality attribute of bison meat. For the in-plant antemortem and postmortem parameters data was collected from three plants in the United States over the course of a year. A total of 2,284 bison (bulls: n = 1,101; cows: n = 199; heifers: n = 984) were included in the study. Antemortem measurements such as distance traveled, vocalization, prod use, mobility, and head bumps were measured, followed by postmortem measurements that included bruise score, live weight, dressing percentage, ribeye area, and instrumental color. Approximately 97% of bison (n = 2,213) had at least one bruise. The average distance traveled from producer to slaughter plant was (mean ±â€…SD; 823 ±â€…583 km) and the average dressing percentage was (mean ±â€…SD; 60.5 ±â€…3.3%). Average (mean ±â€…SD) fat thickness and ribeye area were 1.4 ±â€…1.1 cm and 62.6 ±â€…9.8 cm2, respectively. Approximately 30% (n = 676) of the bison in this study head bumped between 1 and 5 times in the restraining chute or the single-file gate before being stunned. Linear regression indicated that differences in lean a* were associated with plant, number of head bumps in the chute, ribeye area, fat thickness, live weight, and sex class (P < 0.05). Logistic regression indicated that season, sex class, live weight, plant, and season were associated with differences (P < 0.05) in bruising. These results can be used as a baseline for current production parameters and serve as the foundation for future research to monitor improvement.

This project evaluated bison industry stakeholder perceptions on management, animal welfare, and meat quality with in-person and online surveys. Additionally, multiple live animal factors were measured to benchmark their influence on specific meat quality attributes. From the stakeholder surveys, animal handling, bison behavior, employee training, facility design, and transportation duration were identified as the most critical factors that could impact animal welfare in the bison production system. Moreover, the stakeholders understood that animal welfare is a critical component for bison production and that it directly affects meat quality. Live animal production parameters such as distance traveled, season, number of head bumps in the chute, sex class, and live weight were associated with differences in fat thickness, ribeye area, blood splash presence, and instrumental color of bison meat. The results from this study can be used as a baseline for industry improvements and future research.

Benchmarking current preslaughter management factors, welfare indicators, and meat quality outcomes at commercial fed cattle processing facilities in the United States.

Preslaughter management factors and their impacts on cattle welfare and meat quality are well documented in current literature. However, certain management factors related to transportation and lairage are underrepresented. Benchmarking preslaughter management factors that can impact welfare and meat quality outcomes will allow the industry to identify areas for improvement. The objective of the current study was to benchmark preslaughter management factors for a nationwide sample of commercial fed cattle processing facilities. Five processing facilities in the West, Midwest, and Southwest regions of the United States were sampled from March 2021 to July 2022. Data were collected on a total of n = 637 slaughter lots representing n = 87,220 head of cattle. Variables of interest included general cattle characteristics, distance traveled to the plant, truck wait times to unload, environmental conditions, lairage density, and lairage duration. Additionally, mobility was scored using a four-point locomotion scale (one being normal, not lame, and four being extremely reluctant to move). Carcasses were also observed for bruising using the following scale: no bruises, bruises smaller or larger than a deck of cards, and having multiple bruises. Descriptive statistics were performed on the data at the lot and individual animal level. On average, cattle traveled 155.8 ±â€…209.6 km (mean ±â€…SD) from the feedlot to the processing facility and waited 30.3 ±â€…39.7 min to unload. Once in lairage pens, cattle were held for 200.7 ±â€…195.0 min. The mean lairage stocking density was 3.1 ±â€…2.0 m2 per head. A majority of the cattle scored a mobility score of 1 (n = 77,645, 91.8%), 7.8% (n = 6,125) were scored as a two and the remaining less than one percent of cattle were scored as either a 3 or 4 (n = 265). Carcasses with bruises less than or equal to the size of a deck of cards (n = 22,672, 27.1%) were less frequent than bruises measuring greater than the size of a deck of cards (n = 34,427, 42.6%). Of carcasses that were bruised, 65.2% (n = 39,856) had multiple bruises of varying size. This baseline data on preslaughter management factors identifies opportunities for improvement in wait times, lairage densities, and factors that cause bruising. Future studies should explore the relationships between these factors and their impacts on welfare and meat quality, report the economic value of these outcomes, and explore industry acceptability and adoptability of optimal preslaughter management practices.

A current review of U.S. beef flavor II: Managing beef flavor.

Beef flavor continues to be one of the largest drivers of beef demand and a differentiation point of beef from other competing proteins. Tenderness has long been identified as the most important palatability trait for consumer satisfaction. However, as technological advancements and industry practices evolve and improve in response to tenderness management, flavor has emerged as a key driver of consumer satisfaction. In response, the beef industry has recently invested in research focused on beef flavor development, measurement, and management to better understand the factors impacting flavor and help beef maintain this advantage. The current review paper is the second of two such papers focused on summarizing the present knowledge and identifying knowledge gaps. While the other review focuses on current practices related to beef flavor measurement, this review will cover research findings related to beef flavor management. Numerous production and product management factors influence beef flavor. Pre-harvest factors including marbling level, animal genetics/cattle type, diet, and animal age, can influence beef flavor. Moreover, numerous post-harvest product management factors, including product type, aging length and conditions, cookery methods, product enhancement, muscle-specific factors, packaging, retail display factors, and antimicrobial interventions, have all been evaluated for their impact on beef flavor characteristics. Results from numerous studies evaluating many of these factors will be outlined within this review in order to present management and production chain factors that can influence beef flavor.

Establishing the link between microbial communities in bovine liver abscesses and the gastrointestinal tract.

BACKGROUND: Liver abscesses (LAs) are one of the most common and important problems faced by the beef industry. The most efficacious method for the prevention of LAs in North America is through dietary inclusion of low doses of antimicrobial drugs such as tylosin, but the mechanisms by which this treatment prevents LAs are not fully understood. LAs are believed to result from mucosal barrier dysfunction in the gastrointestinal tract (GIT) allowing bacterial translocation to the liver via the portal vein, yet differences in the GIT microbiome of cattle with and without LAs have not been explored. Here, we characterized microbial communities from LAs, rumen, ileum, and colon from the same cattle for the first time. RESULTS: Results demonstrate that tylosin supplementation was associated with differences in microbial community structure in the rumen and small intestine, largely because of differences in the predominance of Clostridia. Importantly, we show for the first time that microbial communities from multiple LAs in one animal's liver are highly similar, suggesting that abscesses found at different locations in the liver may originate from a localized source in the GIT (rather than disparate locations). A large portion of abscesses were dominated by microbial taxa that were most abundant in the hindgut. Further, we identified taxa throughout the GIT that were differentially abundant between animals with and without liver abscesses. Bifidobacterium spp.-a bacteria commonly associated with a healthy GIT in several species-were more abundant in the rumen and ileum of animals without LAs compared to those with LAs. CONCLUSIONS: Together these results provide the first direct comparison of GIT and LA microbial communities within the same animal, add considerable evidence to the hypothesis that some LA microbial communities arise from the hindgut, and suggest that barrier dysfunction throughout the GIT may be the underlying cause of LA formation in cattle.

Distinct myofibrillar sub-proteomic profiles are associated with the instrumental texture of aged pork loin.

Fresh pork tenderness contributes to consumer satisfaction with the eating experience. Postmortem proteolysis of proteins within and between myofibrils has been closely linked with pork tenderness development. A clear understanding of the molecular features associated with pork tenderness development will provide additional targets and open the door to new solutions to improve and make pork tenderness development more consistent. Therefore, the objective was to utilize liquid chromatography and mass spectrometry with tandem mass tag (TMT) multiplexing to evaluate myofibrillar sub-proteome differences between pork chops of different instrumental star probe values. Pork loins (N = 120) were collected from a commercial harvest facility at 24 h postmortem. Quality and sensory attributes were evaluated at 24 h postmortem and after ~2 weeks of postmortem aging. Pork chops were grouped into 4 groups based on instrumental star probe value (group A,x¯â€…= 4.23 kg, 3.43 to 4.55 kg; group B,x¯â€…= 4.79 kg, 4.66 to 5.00 kg; group C,x¯â€…= 5.43 kg, 5.20 to 5.64 kg; group D,x¯â€…= 6.21 kg, 5.70 to 7.41 kg; n = 25 per group). Myofibrillar proteins from the samples aged ~2 wk were fractionated, washed, and solubilized in 8.3 M urea, 2 M thiourea, and 1% dithiothreitol. Proteins were digested with trypsin, labeled with 11-plex isobaric TMT reagents, and identified and quantified using a Q-Exactive Mass Spectrometer. Between groups A and D, 54 protein groups were differentially abundant (adjusted P < 0.05). Group A had a greater abundance of proteins related to the thick and thin filament and a lesser abundance of Z-line-associated proteins and metabolic enzymes than group D chops. These data highlight that distinct myofibrillar sub-proteomes are associated with pork chops of different tenderness values. Future research should evaluate changes immediately and earlier postmortem to further elucidate myofibrillar sub-proteome differences over the postmortem aging period.

A primary goal of meat production is to efficiently produce safe, high-quality products. Competing interests within the goal complicate this seemingly simple aspiration. Consequently, it is necessary to emphasize efforts to enhance our comprehension of biological and molecular factors that influence quality, safety, and efficient meat production. This experiment aimed to define the proteomic profiles of the myofibrillar fraction of fresh pork with differing quality traits. Myofibrils from aged pork chops with a range of tenderness levels were used to achieve this objective. Fifty-four proteins were differentially abundant between the divergent tenderness groups. This was due to the expression profile of proteins in muscle and/or changes in proteins in the myofibrillar fraction during postmortem aging. These results inform and direct the development of antemortem and postmortem applications to ensure success in producing high-quality pork.

Efficacy of Antimicrobial Spray Treatments in Reducing Salmonella enterica Populations on Chilled Pork.

Studies reporting on alternative antimicrobial interventions for pathogen control on chilled pork carcasses and cuts are limited. In this study, the antimicrobial effects of various spray treatments against Salmonella enterica inoculated on skin-on pork samples were evaluated. Chilled pork jowls were portioned (10 by 5 by 1 cm) and inoculated, on the skin side, with a mixture of six S. enterica serotype strains to target levels of 6 to 7 log CFU/cm2 (high inoculation level) or 3 to 4 log CFU/cm2 (low inoculation level). Samples were then left nontreated (control) or were treated (10 s) using a laboratory-scale spray cabinet with water, formic acid (1.5%), a proprietary blend of sulfuric acid and sodium sulfate (SSS, pH 1.2), peroxyacetic acid (PAA, 400 ppm), or PAA (400 ppm) that was pH-adjusted (acidified) with acetic acid (1.5%), formic acid (1.5%), or SSS (pH 1.2). Samples (n = 6) were analyzed for Salmonella populations after treatment application (0 h) and after 24 h of refrigerated (4°C) storage. Irrespective of inoculation level, all spray treatments effectively reduced (P < 0.05) Salmonella levels immediately following their application. Overall, pathogen reductions for the chemical treatments, compared to the respective high and low inoculation level nontreated controls, ranged from 1.2 to 1.9 log CFU/cm2 (high inoculation level) and 1.0 to 1.7 log CFU/cm2 (low inoculation level). Acidification of PAA with acetic acid, formic acid, or SSS did not (P ≥ 0.05) enhance the initial bactericidal effects of the nonacidified PAA treatment. Salmonella populations recovered from all treated samples following 24 h of storage were, in general, similar (P ≥ 0.05) or up to 0.6 log CFU/cm2 lower (P < 0.05) than those recovered from samples analyzed immediately after treatment application. The results of the study may be used by processing establishments to help identify effective decontamination interventions for reducing Salmonella contamination on pork.

Characterizing the sarcoplasmic proteome of aged pork chops classified by purge loss.

Unpredictable variation in quality, including fresh pork water-holding capacity, remains challenging to pork processors and customers. Defining the diverse factors that influence fresh pork water-holding capacity is necessary to make progress in refining pork quality prediction methods. The objective was to utilize liquid chromatography and mass spectrometry coupled with tandem mass tag (TMT) multiplexing to evaluate the sarcoplasmic proteome of aged pork loins classified by purge loss. Fresh commercial pork loins were collected, aged 12 or 14 d postmortem, and pork quality and sensory attributes were evaluated. Chops were classified into Low (N = 27, average purge = 0.33%), Intermediate (N = 27, average purge = 0.72%), or High (N = 27, average purge = 1.19%) chop purge groups. Proteins soluble in a low-ionic strength buffer were extracted, digested with trypsin, labeled with 11-plex isobaric TMT reagents, and detected using a Q-Exactive Mass Spectrometer. Between the Low and High purge groups, 40 proteins were differentially (P < 0.05) abundant. The Low purge group had a greater abundance of proteins classified as structural and contractile, sarcoplasmic reticulum and calcium regulating, chaperone, and citric acid cycle enzymes than the High purge group. The presence of myofibrillar proteins in the aged sarcoplasmic proteome is likely due to postmortem degradation. These observations support our hypothesis that pork chops with low purge have a greater abundance of structural proteins in the soluble protein fraction. Together, these and other proteins in the aged sarcoplasmic proteome may be biomarkers of pork water-holding capacity. Additional research should establish the utility of these proteins as biomarkers early postmortem and over subsequent aging periods.

Fresh pork can vary in its ability to retain water­commonly termed as its water-holding capacity­where a greater water-holding capacity means it retains more water as it is cut, packaged, and stored. However, commercial pork loins have considerable variability in their water-holding capacity, which can impact the consumer's eating experience. This study aimed to examine water-soluble proteins from aged commercial pork chops and to identify and quantify these proteins with mass spectrometry to confirm the previous observation that the degradation of specific structural proteins is associated with greater water-holding capacity. This analysis identified 40 proteins differentially abundant between pork chops with varying water-holding capacities. Pork chops with greater water-holding capacity had a greater abundance of proteins classified as structural and contractile, calcium regulating, and chaperone. Metabolic proteins were also differentially abundant in aged pork loins with differing water-holding capacity. This study confirmed previous observations that the degradation of key structural proteins is associated with greater water-holding capacity while identifying new proteins that may be biomarkers for water-holding capacity.

Evaluating the ability of rapid evaporative ionization mass spectrometry to differentiate beef palatability based on consumer preference.

Rapid Evaporative Ionization Mass Spectrometry (REIMS) is a type of ambient ionization mass spectrometry, which enables real-time evaluation of several complex traits from a single measurement. The objective of this study was to evaluate the capability of REIMS analysis of raw samples coupled with chemometrics to accurately identify and predict cooked beef palatability. REIMS analysis and consumer sensory evaluation were conducted for beef arm center roasts (n = 20), top loin steaks (n = 20), top sirloin steaks (n = 20), and 20% lipid ground beef (n = 20). These data were used to train predictive models for six classification sets representing different sensory traits. The maximum prediction accuracies achieved (from high to low): beefy flavor acceptance (86.25%), juiciness acceptance (83.75%), overall acceptance (81.25%), overall flavor acceptance (81.25%), grilled flavor acceptance (78.75%), and tenderness acceptance (75%). The current study demonstrates that REIMS analysis of raw meat has the potential to predict and classify cooked beef palatability. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-022-05562-6.

Tandem mass tag labeling to assess proteome differences between intermediate and very tender beef steaks.

Tenderness is considered as one of the most important quality attributes dictating consumers' overall satisfaction and future purchasing decisions of fresh beef. However, the ability to predict and manage tenderness has proven very challenging due to the numerous factors that contribute to variation in end-product tenderness. Proteomic profiling allows for global examination of differentially abundant proteins in the meat and can provide new insight into biological mechanisms related to meat tenderness. Hence, the objective of this study was to examine proteomic profiles of beef longissimus lumborum (LL) steaks varying in tenderness, with the intention to identify potential biomarkers related to tenderness. For this purpose, beef LL muscle samples were collected from 99 carcasses at 0 and 384 h postmortem. Based on Warner-Bratzler shear force values at 384 h, 16 samples with the highest (intermediate tender, IT) and lowest (very tender, VT) values were selected to be used for proteomic analysis in this study (n = 8 per category). Using tandem mass tag-based proteomics, a total of 876 proteins were identified, of which 51 proteins were differentially abundant (P < 0.05) between the tenderness categories and aging periods. The differentially identified proteins encompassed a wide array of biological processes related to muscle contraction, calcium signaling, metabolism, extracellular matrix organization, chaperone, and apoptosis. A greater (P < 0.05) relative abundance of proteins associated with carbohydrate metabolism and apoptosis, and a lower (P < 0.05) relative abundance of proteins involved in muscle contraction was observed in the VT steaks after aging compared with the IT steaks, suggesting that more proteolysis occurred in the VT steaks. This may be explained by the greater (P < 0.05) abundance of chaperonin and calcium-binding proteins in the IT steaks, which could have limited the extent of postmortem proteolysis in these steaks. In addition, a greater (P < 0.05) abundance of connective tissue proteins was also observed in the IT steaks, which likely contributed to the difference in tenderness due to added background toughness. The established proteomic database obtained in this study may provide a reference for future research regarding potential protein biomarkers that are associated with meat tenderness.

Among all the eating quality attributes of beef, tenderness is considered an essential factor influencing consumers' overall satisfaction and future purchasing decisions. However, managing and predicting tenderness of meat products is challenging for the meat industry, as many factors can influence this attribute. The goal of this research was to examine variations in protein abundance between two categories of beef strip steaks varying in tenderness, with the intention to identify proteins related to beef tenderness/toughness. Overall, the results from this study suggest that tender steaks experienced greater protein degradation during aging than tougher steaks, which likely contributed to their improved tenderness. Furthermore, a greater abundance of connective tissue proteins, which are associated with meat toughness, was observed in the tougher steaks. Our results collectively indicate that the difference in tenderness between the two groups of steaks may be due to multiple proteins involved in several biological processes.

Pulmonary arterial pressure in fattened Angus steers at moderate altitude influences early postmortem mitochondria functionality and meat color during retail display.

Pulmonary hypertension is a noninfectious disease of cattle at altitudes > 1524 m (5,000 ft). Mean pulmonary arterial pressures (PAP) are used as an indicator for pulmonary hypertension in cattle. High PAP cattle (≥50 mmHg) entering the feedlot at moderate elevations have lower feed efficiency as compared to low PAP cattle (< 50 mmHg). The impact of pulmonary arterial pressure on mitochondrial function, oxidative phosphorylation (OXPHOS) protein abundance, and meat color was examined using longissimus lumborum (LL) from high (98 ± 13 mmHg; n = 5) and low (41 ± 3 mmHg; n = 6) PAP fattened Angus steers (live weight of 588 ± 38 kg) during early postmortem period (2 and 48 h) and retail display (days 1 to 9), respectively. High PAP muscle had greater (P = 0.013) OXPHOS-linked respiration and proton leak-associated respiration than low PAP muscles at 2 h postmortem but rapidly declined to be similar (P = 0.145) to low PAP muscle by 48 h postmortem. OXPHOS protein expression was higher (P = 0.045) in low PAP than high PAP muscle. During retail display, redness, chroma, hue, ratio of reflectance at 630 and 580 nm, and metmyoglobin reducing activity decreased faster (P < 0.05) in high PAP steaks than low PAP. Lipid oxidation significantly increased (P < 0.05) in high PAP steaks but not (P > 0.05) in low PAP. The results indicated that high PAP caused a lower OXPHOS efficiency and greater fuel oxidation rates under conditions of low ATP demand in premortem beef LL muscle; this could explain the lower feed efficiency in high PAP feedlot cattle compared to low PAP counterparts. Mitochondrial integral function (membrane integrity or/and protein function) declined faster in high PAP than low PAP muscle at early postmortem. LL steaks from high PAP animals had lower color stability than those from the low PAP animals during simulated retail display, which could be partially attributed to the loss of muscle mitochondrial function at early postmortem by ROS damage in high PAP muscle.

The impact of pulmonary arterial pressure (PAP) on mitochondrial function, oxidative phosphorylation protein abundance, and meat color was examined using longissimus lumborum (LL) from high (98 ± 13 mmHg) and low (41 ± 3 mmHg) PAP fattened Angus steers (live weight of 588 ± 38 kg) during early postmortem period (2 and 48 h) and retail display (days 1 to 9), respectively. The results indicated that high PAP caused a lower oxidative phosphorylation efficiency and greater fuel oxidation rates under conditions of positive energy balance in beef LL muscle. This could explain the lower feed efficiency in high PAP feedlot cattle compared to low PAP counterparts. Mitochondrial integral function declined faster in high PAP than low PAP muscle at early postmortem. LL steaks from high PAP animals had lower color stability than those from the low PAP animals during simulated retail display, which could be partially attributed to the loss of muscle mitochondrial function at early postmortem in high PAP muscle.

An early-postmortem metabolic comparison among three extreme acute heat stress temperature settings in chicken breast muscle.

Normally, preslaughter acute heat stress could accelerate postmortem glycolysis and impair chicken breast (pectoralis major muscle) quality. However, previous studies indicated that it might be different when the acute heat stress temperature rises to an extreme range (above 35 °C). Therefore, this study's objectives were to compare the pH decline, glycolytic enzyme activity, and AMP-activated protein kinase (AMPK) phosphorylation at early postmortem among three extreme acute heat stress temperature settings: a control group (36 °C) and two experimental groups (38 °C and 40 °C). Although the temperature did not affect glycogen phosphorylase a and pyruvate kinase activity, there was a decrease in pH decline rate, phosphofructokinase-1 activity, and phospho-AMPK-α[Thr172] within 4 h postmortem when temperature increased from 36 to 40 °C. Temperature also affected hexokinase activity, with the 36 °C-group having the highest activity. The results of the current study, for the first time, indicated that postmortem metabolic rate in chicken breast muscle could be changed by acute heat stress temperature setting at extreme range.

Nix Pro Color Sensor provides comparable color measurements to HunterLab colorimeter for fresh beef.

The HunterLab MiniScan (HunterLab) colorimeter is used in meat quality research worldwide for measuring meat color; however, the Nix Pro Color Sensor (Nix) could be a less expensive alternative that is easier to operate. Therefore, the objective of this study was to compare the two colorimeters to objectively evaluate fresh beef color. Longissimus thoracis muscle from one side of A maturity beef carcasses (n = 200) was evaluated using both the HunterLab (3 technical replicate scans) and Nix (3, 5, 7, and 9 technical replicate scans) colorimeters. The correlation between the HunterLab and Nix for L* (lightness), a* (redness), and b* (yellowness) values ranged between r = 0.80 to 0.85 and the Bland Altman Limits of Agreement analysis indicated good agreement between the Nix and HunterLab colorimeters for all the color parameters. These results indicated that the Nix colorimeter could be a viable alternative for HunterLab colorimeters.

Evaluation of Immersion and Spray Applications of Antimicrobial Treatments for Reduction of Campylobacter jejuni on Chicken Wings.

The decontamination efficacy of antimicrobial treatments against Campylobacter jejuni on chicken wings was evaluated. Chicken wings surface-inoculated with C. jejuni (3.9 log colony-forming units [CFU]/mL) were left untreated (control) or were treated by immersion (5 s) or in a spray cabinet (4 s) with water, a sulfuric acid and sodium sulfate blend (SSS; pH 1.2), formic acid (1.5%), peroxyacetic acid (PAA; 550 ppm), or PAA (550 ppm) that was pH-adjusted (acidified) with SSS (pH 1.2) or formic acid (1.5%). All evaluated immersion and spray chemical treatments effectively (p < 0.05) lowered C. jejuni populations on chicken wings. Spray application of chemical treatments resulted in immediate pathogen reductions ranging from 0.5 to 1.2 log CFU/mL, whereas their application by immersion lowered initial pathogen levels by 1.7 to 2.2 log CFU/mL. The PAA and acidified PAA treatments were equally (p ≥ 0.05) effective at reducing initial C. jejuni populations, however, following a 24 h refrigerated (4 °C) storage period, wings treated with acidified PAA had lower (p < 0.05) pathogen levels than samples that had been treated with PAA that was not acidified. Findings of this study should be useful to the poultry industry in its efforts to control Campylobacter contamination on chicken parts.

Effects of differing withdrawal times from ractopamine hydrochloride on residue concentrations of beef muscle, adipose tissue, rendered tallow, and large intestine.

Ractopamine hydrochloride (RAC) is a beta-agonist approved by the U.S. Food and Drug Administration (FDA) as a medicated feed ingredient for cattle during the final days of finishing to improve feed efficiency and growth. Maximum residue limits and U.S. FDA residue tolerances for target tissues have defined management practices around RAC usage in the U.S. However, many countries have adopted zero tolerance policies and testing of off-target tissues, presenting a major challenge for international export. Therefore, the objective this study was to determine the necessary withdrawal time among cattle group-fed RAC to achieve residue concentrations below tolerance levels in muscle and off-target tissues. Specifically, both total and parent RAC residues were quantified in muscle, adipose tissue, rendered tallow, and large intestines from animals group-fed RAC and subjected to withdrawal 2, 4, or 7 days before harvest. Ractopamine (parent and total) residues were below the assay limit of detection (< 0.12 ng/g) in all muscle and adipose tissue samples from animals in control groups (no RAC). However, RAC residues were detectable, but below the limit of quantitation, in 40% of tallow and 17% of large intestine samples from control animals. As expected, mean RAC residue concentrations in muscle, adipose tissue, and large intestine samples decreased (P < 0.05) as the RAC withdrawal duration (days) was extended. Irrespective of RAC withdrawal duration, mean parent RAC residue concentrations in muscle, adipose tissue, and large intestine ranged from 0.33 to 0.76 ng/g, 0.16 to 0.26 ng/g, 3.97 to 7.44 ng/g, respectively and all tallow samples were > 0.14 ng/g (detectable but below the limit of quantitation). Results of this study provide a baseline for the development of management protocol recommendations associated with withdrawal following group-feeding of RAC to beef cattle in countries that allow RAC use and intend to export to global markets which may be subject to zero tolerance policies and off-target tissue testing.

Tandem mass tagged dataset used to characterize muscle-specific proteome changes in beef during early postmortem period.

Bovine longissimus lumborum (LL) and psoas major (PM) muscles biopsy samples were collected from four carcasses (n = 4) at 45 min, 12 h, and 36 h postmortem from a commercial beef processing facility. Proteins present in the early postmortem LL and PM proteomes were identified and quantified using tandem mass tag (TMT) labelled, fractionated peptides coupled to liquid chromatography tandem mass spectrometry (LC-MS/MS). The data are supplied in this article and are related to "Tandem mass tag labeling to characterize muscle-specific proteome changes in beef during early postmortem period" by Zhai et al. [1].

Tandem mass tag labeling to characterize muscle-specific proteome changes in beef during early postmortem period.

Previous research has indicated that variation in the proteome profile of longissimus lumborum (LL) and psoas major (PM) post-rigor influences meat quality attributes such as tenderness and color stability during retail display. Tandem mass tag (TMT) labeling is a chemical labeling approach using isobaric mass tags for accurate mass spectrometry-based quantification and identification of biological macromolecules. The objective of this study was to use TMT labeling to examine proteome profile variation between beef LL and PM during the early postmortem period (45 min, 12 h, and 36 h). We identified a total of 629 proteins, of which 71 were differentially abundant (fold change > 1.5, P < .05) from three comparisons between the muscles (PM vs. LL at 45 min, 12 h and 36 h). These proteins were mainly involved in oxidative phosphorylation and ATP-related transport, tricarboxylic acid cycle, NADPH regeneration, fatty acid degradation, muscle contraction, calcium signaling, chaperone activity, oxygen transport, as well as degradation of the extracellular matrix. At early postmortem, more abundant antiapoptotic proteins in LL could cause high metabolic stability, enhanced autophagy, and delayed apoptosis, while overabundant metabolic enzymes and pro-apoptotic proteins in PM could accelerate the generation of reactive oxygen species and initiation of cell death. SIGNIFICANCE: Longissimus lumborum and psoas major are two highly valuable cuts in beef carcass exhibiting different quality attributes such as color and tenderness, partly due to their distinct muscle fiber proportion and metabolic property. We characterized the proteomic change of these two muscles at early postmortem using tandem mass tag labeling for the first time, which highlighted the potential relationships between metabolism, cell death, and color stability. Our work provides a new perspective on muscle-to-meat conversion, especially on the potential effect of muscle-specific cell death on meat color stability.

Carbon Chain Length of Lipid Oxidation Products Influence Lactate Dehydrogenase and NADH-Dependent Metmyoglobin Reductase Activity.

The biochemical basis of lower metmyoglobin reducing activity (MRA) in high-oxygen modified atmospheric packaged (HiOx-MAP) beef than those in vacuum and polyvinyl chloride (PVC) packaging is not clear. To explore this, the effects of lipid oxidation products with varying carbon chain length on lactate dehydrogenase (LDH) and NADH-dependent metmyoglobin reductase activity were evaluated. Surface color, MRA, and lipid oxidation of beef longissimus lumborum steaks (n = 10) were measured during 6-day display. Further, two enzymes, LDH and NADH-dependent metmyoglobin reductase (n = 5), critical for MRA were incubated with or without (control) lipid oxidation products of varying carbon chain length: malondialdehyde (3-carbon), hexenal (6-carbon), and 4-hydroxynonenal (9-carbon). Steaks in HiOx-MAP had greater (P < 0.05) redness than vacuum and PVC, but had lower (P < 0.05) MRA and greater (P < 0.05) lipid oxidation on day 6. LDH and NADH-dependent metmyoglobin reductase activities were differentially influenced by lipid oxidation products (P < 0.05). The results indicate that the difference in reactivity of various lipid oxidation products on LDH (HNE > MDA = hexenal) and NADH-dependent metmyoglobin reductase (HNE = MDA > hexenal) activity could be responsible for lower MRA in HiOx-MAP.