COMPARISON OF USDA QUALITY GRADE WITH TENDERTEC FOR THE ASSESSMENT OFBEEF PALATABILITY

Carcasses (n = 265) selected to differ in USDA yield grade were evalua ted by expert graders and assessed for tenderness with the Tendertec M ark III Beef Grading Instrument. Tendertec measurements were collected on longissimus lumborum muscles in both sides of each carcass. During fabrication of each left carcass side, a rib section (later converted into three steaks) was removed for aging and subsequent sensory panel evaluation at 14 d and for Warner-Bratzler shear force measurements a t 14 and 28 d. Correlation coefficients for repeatability of Tendertec output variables, between left and right carcass sides, were .57, .44 , .70, and .65 for Area-2, Area-B2, Power-2, and Power-2B, respectivel y. Correlations between Tendertec output variables and Warner-Bratzler shear force evaluations performed on steaks aged 14 or 28 d were not different from zero. Sensory panel ratings for amount of connective ti ssue were correlated (P <.01) with Tendertec output variables Area-2 a nd Area-2B (r = -.168 and -.154, respectively), and ratings for overal l tenderness were correlated (P <.05) with the Area-2 output variable (r = -.131) but the coefficients were very low. Segregation analysis, using Tendertec output variables Area-2 and Power-2, significantly (P <.05) stratified sensory panel ratings for connective tissue amount an d overall tenderness. Even though the Tendertec probe detected some di fferences in connective tissue contributions to rib steak tenderness, it was not better than USDA quality grade at segmenting A-maturity car casses into anticipated tenderness outcomes, and thus its applicabilit y as a grading instrument may be limited to use on more mature beef ca rcasses.