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United States Department of Agriculture

Agricultural Research Service

Title: Tenderness Classification of Beef. Ii. Design and Analysis of a System to Measure Beef Longissimus Shear Force under Commercial Processing Conditions

Authors
item Shackelford, Steven
item Wheeler, Tommy
item Koohmaraie, Mohammad

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 17, 1998
Publication Date: N/A

Interpretive Summary: Variation in tenderness continues to be a major concern of beef retailers and restaurateurs because the present beef quality grading system does not accurately predict the eating quality of beef. Thus, development of an accurate system to predict or measure meat tenderness is a high priority of the beef industry. In the present experiment, we developed a rapid, simple method for on-line evaluation of tenderness based on modifications to the Warner-Bratzler shear force test, a mechanical measurement of meat tenderness. The process is completed during the 10 minutes that the carcasses are typically held to allow the ribeye to brighten for quality grading. Thus, tenderness classification does not interfere with production rates. Tenderness classification conducted at 3 days after slaughter on carcasses from youthful, grain- fed steers and heifers predicted with 99% accuracy whether or not ribeye steaks from a given carcass would be "Tender" after 14 days of cooler aging. Thus, tenderness classification could be used to accurately segregate beef carcasses into expected palatability groups. Use of tenderness classification would greatly increase the value of lean, tender carcasses, which are currently penalized by the U.S. beef marketing system because they lack sufficient marbling to grade USDA Choice.

Technical Abstract: Our objective was to evaluate the efficacy of a system for tenderness classification of beef and to describe the potential design of an automated tenderness classification system. Carcasses to be tenderness classified would be slaughtered and chilled conventionally. At the time carcasses are normally ribbed for determination of quality and yield grade, a 2.54-cm thick rib steak would be removed from the 12th rib region of the right side of each carcass. The steak would be trimmed free of s.c. fat and bone and rapidly cooked. A sample would be removed from the cooked longissimus for measurement of shear force. Shear force would be measured using an electronic testing machine and the data would be captured electronically into the packing plant's computer data base. The process would be completed during the 10 minutes that the ribeye blooms for quality grading and, thus, sorting of carcasses for fabrication would proceed conventionally. The repeatability of slice shear force (SSF), as determined by evaluation of duplicate samples from 204 A-maturity carcasses, was .89. Carcasses were classified into three groups based on SSF (< 23, 23 to 40, and > 40 kg) at 3 d postmortem which differed (P < .001) in mean trained sensory panel tenderness rating (7.4, 6.7, and 4.2) and the percentage (100, 100, and 20%) of samples rated "Slightly Tender" or higher at 14 d postmortem. All carcasses with SSF < 23 kg at 3 d postmortem were rated "Moderately Tender" or higher at 14 d postmortem. Thus, tenderness classification could be used to accurately segregate beef carcasses into expected tenderness groups.

Last Modified: 7/22/2014