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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

2017 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
This is the final report for the 5-year project 3040-31430-005-00D which terminated July 31, 2017 and was replaced with project 3040-31430-006-00D “Strategies to Optimize Meat Quality and Composition of Red Meat Animals.” Over the lifespan of this research project, significant progress was made in providing the red meat and livestock industries with information and technology to improve meat quality and composition. The capability of the U.S. Meat Animal Research Center beef grading camera system was expanded to include a prediction of meat tenderness and the VQG boneless pork loin grading camera system was developed. The need for objective measurement of pork loin quality was demonstrated as was the conditions under which beef top sirloins could be included in tenderness certification programs. The impact of the growth promotant Zilpaterol hydrochloride on consumer satisfaction and the effect of high pH, dark colored beef on flavor and tenderness was determined. The role of mitochondria in lean color stability and the biological basis for variation in beef tenderness among packing plants and quality grade programs was determined. Strategies for improving meat tenderness with blade tenderization or freezing and thawing were developed and the impact on quality of food safety interventions for blade tenderized meat cuts was characterized. Objective 1: Animal stress before harvest results in abnormally high pH of the meat which makes the meat dark and results in a discounted carcass grade which reduces the value of the carcass for both the producer and the processor. Evaluation of top loin steaks from these dark-cutter carcasses determined that slightly dark top loin steaks were less tender than normal colored top loin steaks and are likely to be included in routine U.S. Select and U.S. Choice product lines. These results indicate carcasses with slightly dark lean should not be included in U.S. Choice and U.S. Select products and that a mitigation strategy is needed to improve the tenderness of meat from those carcasses thereby increasing consumer satisfaction with beef. Further work on dark-cutting beef determined that muscles from carcasses exhibiting the dark ribeye condition have greater concentrations of mitochondria and different muscle physiology than their normal cohorts making them less able to deal with stress. This was the first identification of a pre-existing difference in live animals that produce carcasses with dark colored ribeyes. Continuing work in the next project plan may lead to strategies to reduce or eliminate incidence of the dark ribeye condition. Previously, the ß adrenergic agonist Zilpaterol hydrochloride was demonstrated to have a large negative effect on instrumental measures of beef tenderness. The significance of that data was confirmed by showing that consumer ratings were lower for steaks from animals administered Zilpaterol hydrochloride compared to controls after either typical or extended postmortem aging time. This finding was used by the beef industry to temper its use of lean growth strategies and mitigate the impact of ß adrenergic agonists on beef tenderness. Consumer purchase decisions for meat are largely determined by product appearance, especially lean color. Greater understanding of the biological basis for variation in lean color stability was gained by demonstrating that animals possessing less efficient muscle mitochondrial function produce muscle with less lean color stability. This finding may lead to genetic or management strategies to improve lean color stability saving millions of dollars per year in wasted product. This work is continuing in the next project plan. Through genetics and management of pigs and carcasses, the pork industry strives to improve pork quality. Much of the evaluation of product quality is based on assessment of the loin. It was determined that pork loin quality is not indicative of fresh belly or fresh and processed ham quality. To understand whole carcass quality, loin, belly, and fresh and processed ham characteristics must be evaluated individually. This finding will be used by the pork industry as it develops a pork grading system. It was determined that variation in meat tenderness among beef packing plant and quality grade programs was related to variation in muscle shortening during chilling. These findings will allow the beef industry to develop effective strategies to optimize tenderness. Ultimately, this should lead to increased consumer satisfaction and drive demand for U.S. beef. It was determined that freezing, then thawing and aging beef resulted in significant improvement in meat tenderness. This strategy could be implemented for all high-priced meat cuts with high quality expectations to ensure tenderness and improve consumer satisfaction or it could be selectively implemented only on those meat cuts identified as high risk to produce tough steaks. These approaches could be used to improve consumer satisfaction and demand for beef. It was determined that instrumental tenderness measurement with shear force was improved with up to four passes through a blade tenderizer, but more than one had no effect on consumer ratings for overall liking. More than one pass through blade tenderization will not improve consumer satisfaction with top sirloin steaks. Blade tenderization is a common tenderization strategy utilized by beef processors to increase palatability and, thus, consumer satisfaction of beef steaks. It was determined that three novel food safety interventions had minimal effects on beef lean color, lean color stability, and flavor, when applied to cuts of beef prior to blade tenderization and steak cutting. These novel antimicrobial interventions could be used to improve food safety of blade tenderized products without negatively affecting product quality. Under objective 2: Beef carcass instrument grading technology for meat tenderness prediction that obtained USDA-Agricultural Marketing Service (AMS) approval was developed. For the first time, this technology provides the beef processing industry with the ability to measure USDA quality grade, yield grade, and tenderness with the same instrument. Several beef industry entities are considering tenderness-based marketing strategies, which have the potential of increasing beef consumption. The USDA-AMS has developed meat tenderness marketing claims standards. To facilitate meat tenderness marketing programs, the aging time specifications needed for top sirloin inclusion in tenderness marketing claims was determined. Ability to include top sirloins in tenderness claims will facilitate adoption of this marketing strategy. A comparison of objective and subjective assessment of boneless pork loin quality under commercial conditions highlighted the need for objective technology for grading of pork loins in order to control quality variation in pork chops and maximize consumer satisfaction. The National Pork Board is considering development of a pork grading system. The VQG boneless pork loin grading camera was developed that could predict online measures of loin color, marbling, water-holding capacity, and tenderness. Implementation of this tool will allow the industry to implement a pork grading system to identify higher quality pork that could be marketed in a premium program.

1. Development of pork loin in grading system. Because the pork industry lacks an objective method to evaluate meat quality characteristics (tenderness, color, marbling, and water-holding capacity) of boneless loins at commercial processing speeds, ARS scientists at Clay Center, Nebraska developed the VQG pork loin grading camera. Research was conducted under industrial conditions to develop and validate the technology. The VQG team collaborated with pork packing companies to facilitate technology transfer resulting in the first trial installation of VQG in the spring of 2017. In addition to use as a tool to facilitate identification of high quality loins for certain markets, this tool will facilitate genetic selection for pork quality.

2. Identified differentially expressed genes associated with a ham color defect. Cured ham color is of great importance in meeting consumer expectations for ham products. The pork industry recently identified a ham color defect causing consumer dissatisfaction. A very pale portion of one of the ham muscles does not produce normal pink color when processed into cured ham products. ARS scientists at Clay Center, Nebraska began working with pork processors to identify solutions to this problem. Initial efforts to characterize the color defect indicated that the condition occurs in the vast majority of pigs regardless of production system and management practices. Results identified 340 genes that were differentially expressed between the normal and affected portion of the muscle. These results provide information regarding the biological causes of this condition and identified candidate genes that might lead to the development of markers for genetic selection to reduce or eliminate the color defect in ham muscles.

Review Publications
Overholt, M., Arkfeld, E., Mohrhauser, D., King, D.A., Wheeler, T.L., Dilger, A., Shackelford, S.D., Boler, D. 2016. Comparison of variability in pork carcass composition and quality between barrows and gilts. Journal of Animal Science. 94:4415-4426. doi:10.2527/jas2016-0702.
Arkfeld, E.K., Wilson, K.B., Overholt, M.F., Harsh, B.N., Lowell, J.E., Hogan, E.K., Klehm, B.J., Bohrer, B.M., Kroscher, K.A., Peterson, B.C., Stites, C.R., Mohrhauser, D.A., King, D.A., Wheeler, T.L., Dilger, A.C., Shackelford, S.D., Boler, D. 2016. Effects of marketing group on the quality of fresh and cured hams sourced from a commercial processing facility. Journal of Animal Science. 94:5144-5154. doi:10.2527/jas2016-0884.
Arkfeld, E.K., Wilson, K.B., Overholt, M.F., Harsh, B.N., Lowell, J.E., Hogan, E.K., Klehm, B.J., Bohrer, B.M., Mohrhauser, D.A., King, D.A., Wheeler, T.L., Dilger, A.C., Shackelford, S.D., Boler, D. 2016. Pork loin quality is not indicative of fresh belly or fresh and cured ham quality. Journal of Animal Science. 94:5155-5167. doi:10.2527/jas2016-0886.
Overholt, M.F., Arkfeld, E.K., Wilson, K.B., Mohrhauser, D.A., King, D.A., Wheeler, T.L., Dilger, A.C., Shackelford, S.D., Boler, D.D. 2016. Effects of marketing group and production focus on quality and variability of adipose tissue and bellies sourced from a commercial processing facility. Journal of Animal Science. 94:5168-5176. doi:10.2527/jas2016-0975.
Arkfeld, E.K., Mohrhauser, D.A, King, D.A., Wheeler, T.L., Dilger, A.C., Shackelford, S.D., Boler, D.D. 2017. Characterization of variability in pork carcass composition and primal quality. Journal of Animal Science. 95:697-708. doi:10.2527/jas2016.1097.
Artegoitia, V.M., Foote, A.P., Lewis, R.M., King, D.A., Shackelford, S.D., Wheeler, T.L., Freetly, H.C. 2016. Endocannabinoids concentrations in plasma associated with feed efficiency and carcass composition of beef steers. Journal of Animal Science. 94(12):5177-5181. doi:10.2527/jas2016-1025.
Hales Paxton, K.E., Foote, A.P., Jones, S., Shackelford, S.D., Boyd, B.M., Erickson, G.E. 2016. The effects of zilpaterol hydrochloride and shade on blood metabolites of finishing beef steers. Journal of Animal Science. 94(7):2937-2941. doi:10.2527/jas2015-9967.