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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Meat Safety and Quality » Research » Research Project #423446


Location: Meat Safety and Quality

2015 Annual Report

Objective 1: Develop strategies to manage and improve variation in meat quality and composition traits. 1.1: Determine the temperature and pH profiles for optimal quality of modern pork. 1.2: Develop genetic markers for pork lean color stability, tenderness, water holding capacity, intramuscular fat content, sarcomere length, and postmortem proteolysis. 1.3: Evaluation of plasma glucose and lactate levels at exsanguination as predictors of meat quality attributes. 1.4: Evaluate the relationships between mitochondrial abundance and efficiency and animal variation in beef lean color stability. 1.5: Determine seasonal variation in fatty acid profile of belly adipose from first-pull and run-out hogs fed diets differing in fatty acid profile. 1.6: Determine variation in fatty acid profile of belly fat from first-pull and run-out gilts, barrows, and immuno-castrated barrows. Objective 2: Develop non-invasive technology to improve meat quality, composition, and healthfulness traits. 2.1: Develop regression equations for prediction of ribeye (longissimus) area and other value determining characteristics using the laser-enhanced VBG2000 beef carcass grading camera. 2.2: Determine the effect of light source on robustness of regression equations for prediction of marbling score using the laser-enhanced VBG2000 beef carcass grading camera. 2.3: Develop regression equations for prediction of beef fatty acid profiles with on-line visible and near infrared (VISNIR) spectroscopic evaluation of the ribeye (longissimus) and subcutaneous fat during beef carcass grading. 2.4: Develop regression equations for on-line prediction of fatty acid profiles of pork belly fat with VISNIR spectroscopy. Objective 3: Improve product quality and healthfulness, and food animal growth and production efficiencies, through development of alternatives to conventional antimicrobials utilizing novel metagenomic and microbial genomic technologies.

The effects of the interaction of muscle pH and temperature decline on various pork quality traits will be determined. Genetic markers will be identified that can be used to optimize various pork quality traits. Plasma glucose and lactate levels at exsanguination will be evaluated as predictors of meat quality traits. Mitochondrial abundance and efficiency will be evaluated as mechanisms controlling variation in lean color stability. Season, marketing group, and immuno-castration will be investigated as sources of variation in pork fat quality. The USMARC beef carcass grading camera accuracy will be enhanced by developing prediction models using more stable light sources and laser-enhanced placement adjustments. Healthfulness and quality of beef and pork will be improved by developing visible and near-infrared prediction of fatty acid profile of lean and fat. The effect of alternatives to antibiotics such as lysozyme for young piglets on growth and efficiency will be determined. In addition, the potential for improvement of product quality and efficiency will be determined for diet modified gut microbial composition.

Progress Report
Progress under objective 1 includes initiating experiments to determine the optimum parameters for commercial implementation of a freezing process to improve tenderness and minimize water losses after thawing and aging. The first application of pilot lab test of freezing and thawing resulted in too much water loss after thawing. Thawing parameters will be revised for second attempt. In collaboration with University of Illinois, the first half of the data (winter season) were collected for determining the variation in meat quality traits of pork loins from marketing groups out of individual hog finishing barns. First, second and final pull marketings out of two barns each of two genetic lines of hogs were evaluated. Summer season data collection will be completed over the next few months. The meat processing industry identified a pale lean color defect in one muscle from commercial hams that results in undesirable ham color that reduces consumer acceptance. We worked with pork processors to collect preliminary data to quantify and characterize the defect. The condition occurs in the vast majority of pigs regardless of production system and management and causes changes in several muscles characteristics that affect meat quality. Ongoing efforts include determining the biochemical mechanisms and genetic contributions as well as strategies to mitigate the negative impact of the condition on consumer acceptance. Lean color is a primary determinant of consumer beef purchasing decisions. Steaks produced from some animals do not maintain their desirable red color for use in retail markets. In collaboration with scientists from the University of Kentucky, we used proteomics to identify 9 proteins expressed at different levels in color stable steaks relative to color unstable steaks. Ongoing efforts include identifying DNA sequence variation in the genes coding for these proteins to identify single-nucleotide polymorphisms (SNP) that potentially could be used to select for increased beef lean color stability. Under objective 2, experiments were initiated to collect data on boneless pork loins with the camera grading system to develop a tenderness prediction. Additional data collection on 1400 loins from seven different processing plants will be collected over the next ten months.

1. Relationship between top loin tenderness and tenderness of top sirloin and top sirloin cap muscles. Several beef industry entities are considering tenderness-based marketing strategies, which have the potential of increasing beef consumption. The recent development of meat tenderness marketing claims standards by American Society of Testing Materials (ASTM) and USDA-Agricultural Martketing Service (AMS) has given the industry added impetus to implement a tenderness-based marketing system. For retailers to effectively execute a tenderness-based marketing strategy, retailers need to be able to market all loin and rib cuts as certified tender. Yet, the certification protocols do not favor inclusion of top sirloins, which represent substantial retail meat cut feature. Data was needed to determine the extent to which top sirloin could be included in a certified tender program and what postmortem aging specifications are needed to insure a high level of customer satisfaction. ARS researchers at Clay Center, Nebraska, determined that inclusion of the top sirloin in tenderness marketing claim programs was warranted; but, aging specifications should be 7 d greater for top sirloin than top loin depending on which quality grade program it qualifies for. These findings will allow for inclusion of top sirloin in the USDA/ASTM tenderness claims standards, which should greatly facilitate use of this marketing process by retailers and ultimately, increase demand for U.S. beef.

2. Effect of Zilpaterol hydrochloride on consumer acceptance of tenderness of top loin steaks. ß adrenergic agonists have been used in swine, turkey and beef production to increase lean growth efficiency. Zilpaterol hydrochloride is a ß adrenergic agonist that causes a very strong lean growth response in cattle and, thus, has been widely used by beef feedlots. Previously, we have shown a very significant negative impact of Zilpaterol hydrochloride on instrumental measures of beef tenderness. Yet, some members of the beef industry questioned whether this difference could be detected by consumers. ARS researchers at Clay Center, Nebraska, determined that consumer ratings were lower for steaks from animals administered Zilpaterol hydrochloride compared to controls after either 14 (typical) or 35 (extended) days of postmortem aging. This finding will be used by the beef industry as it considers moderation of lean growth strategies and mitigation of the impact of ß adrenergic agonists on beef tenderness.

3. Association between mitochondrial abundance and efficiency and beef lean color stability. Consumer purchase decisions for meat are largely determined by product appearance, especially lean color. Significant animal-to-animal variation in lean color stability of homologous muscles has been documented, yet complete understanding of the biological basis for variation in lean color stability has not been determined. ARS Scientists at Clay Center, Nebraska, demonstrated that animals possessing less efficient muscle mitochondrial function produce muscle with less lean color stability. This finding identifies inherent differences in live animals that produce muscles with insufficient color life and may lead to genetic or management strategies to improve lean color stability.

Review Publications
Canto, A.C., Suman, S.P., Nair, M.N., Li, S., Rentfrow, G., Beach, C.M., Silva, T.J., Wheeler, T.L., Shackelford, S.D., Grayson, A., Mckeith, R., King, D.A. 2015. Differential abundance of sarcoplasmic proteome explains animal effect on beef Longissimus lumborum color stability. Meat Science. 102:90-98.
Tait, R.G., Jr., Shackelford, S.D., Wheeler, T.L., King, D.A., Keele, J.W., Casas, E., Smith, T.P., Bennett, G.L. 2014. CAPN1, CAST, and DGAT1 genetic effects on preweaning performance, carcass quality traits, and residual variance of tenderness in a beef cattle population selected for haplotype and allele equalization. Journal of Animal Science. 92(12):5382-5393.
Duan, Q., Tait, Jr., R.G., Schneider, M.J., Beitz, D.C., Wheeler, T.L., Shackelford, S.D., Cundiff, L.V., Reecy, J.M. 2015. Sire breed effect on beef longissimus mineral concentrations and their relationships with carcass and palatability traits. Meat Science. 106:25-30.
Hales, K.E., Shackelford, S.D., Wells, J., King, D.A., Hayes, M., Brown-Brandl, T.M., Kuehn, L.A., Freetly, H.C., Wheeler, T.L. 2014. Effects of feeding dry-rolled corn-based diets with and without wet distillers grains with solubles and zilpaterol hydrochloride on performance characteristics, and heat stress in finishing beef steers. Journal of Animal Science. 92(9):4023-4033.
Tait Jr, R.G., Shackelford, S.D., Wheeler, T.L., King, D.A., Casas, E., Thallman, R.M., Smith, T.P., Bennett, G.L. 2014. µ-Calpain, calpastatin, and growth hormone receptor genetic effects on preweaning performance, carcass quality traits, and residual variance of tenderness in Angus cattle selected to increase minor haplotype and allele frequencies. Journal of Animal Science. 92(2):456-466.