Evaluation of the Tendertec beef grading instrument to predict the tenderness of steaks from beef carcasses1

Four experiments were conducted, using carcasses from cattle identified for anticipated variability in tenderness (Exp. 1, 2, and 3) and carcasses selected for variability in physiological maturity and marbling score (Exp. 4), to evaluate the ability of the Tendertec Mark III Beef Grading Probe (Tendertec) to predict tenderness of steaks from beef carcasses. In Exp. 1, 2, and 3, longissimus steaks were aged for different periods of time, cooked to a medium degree of doneness (70°C), and evaluated for Warner-Bratzler shear force (WBS) and trained sensory panel ratings. In Exp. 4, longissimus steaks were aged 14 d and cooked to 60, 65, 70, 75, or 80°C for WBS tests and to 65 or 75°C for sensory panel evaluations. Tendertec output variables were not correlated with 1) 24-h calpastatin activity, steak WBS (following 1, 4, 7, 14, 21, or 35 d of aging), or d-14 sensory panel tenderness ratings in Exp. 1 (n = 467 carcasses) or 2) 14-d WBS in Exp. 2 (n = 202 carcasses). However, in Exp. 3 (n = 29 carcasses), Tendertec output variables were correlated (P < 0.05) with