Constraints on establishing threshold levels for Warner-Bratzler shear-force values based on consumer sensory ratings for seven beef muscles

Steaks (n = 560) from US Department of Agriculture (USDA) Choice and Select, including M. gluteobiceps, M. gluteus medius, M. infraspinatus, M. longissimus lumborum, M. rectus femoris, M. triceps brachii and M. vastus lateralis, were evaluated for palatability characteristics and tenderness acceptability by a central-location consumer panel (n = 205 consumers) and Warner-Bratzler shear (WBS) analysis to determine whether threshold values could be identified for these muscles. There were significant interactions for muscle x USDA quality grade for sensory-panel overall like and WBS values. In general, USDA quality grade affected overall like and WBS values for the M. gluteobiceps and M. rectus femoris, but no real differences due to grade were found for the rest of the muscles studied, except for the WBS values for the M. gluteus medius. Regardless of USDA quality grade, the M. infraspinatus had the lowest (P < 0.05) WBS values and was comparable (P > 0.05) in overall like ratings to the M. longissimus lumborum. Percentage of muscles that would be expected to have a tenderness rating 'slightly tender' or higher on the basis of WBS values at the 95% confidence interval ranged from 40% for the M. vastus lateralis to 100% for the M. infraspinatus. There were no clear threshold levels for WBS values that would correspond to certain tenderness like ratings, possibly because of the narrow range of tenderness observed within each muscle. For the muscles studied, how consumers rated them appeared to be independent of the WBS values and may make it difficult to develop WBS thresholds for predicting consumer acceptability of these muscles.