Evaluation of slice shear force as an objective method of assessing beef longissimus tenderness

Experiments were conducted to develop an optimal protocol for measurement o f slice shear force (SSF) and to evaluate SSF as an objective method of ass essing beef longissimus tenderness. Whereas six cylindrical, 1.27-cm-diamet er cores are typically removed from each steak for Warner-Bratzler shear fo rce (WBSF) determination, a single l-cm-thick, Ei-cm-long slice is removed from the lateral end of each longissimus steak for SSF. For either techniqu e, samples are removed parallel to the muscle fiber orientation and sheared across the fibers. Whereas WBSF uses a V-shaped blade, SSF uses a flat bla de with the same thickness (1.016 mm) and degree of bevel (half-round) on t he shearing edge. In Exp. 1, longissimus steaks were acquired from 60 beef carcasses to determine the effects of belt grill cooking rate (very rapid v s rapid) and conditions of SSF measurement (hot vs cold) on the relationshi p of SSF with trained sensory panel (TSP) tenderness rating. Slice shear fo rce was more strongly correlated with TSP tenderness rating when SSF measur ement was conducted immediately after cooking (r = -.74 to -.76) than when steaks were chilled (24 h, 4 degrees C) before SSF measurement (r = -.57 to -.72). When SSF measurement was conducted immediately after cooking, the r elationship of SSF with TSP tenderness rating did not differ among the belt grill cooking protocols used to cook the SSF steak. In Exp. 2, longissimus steaks were acquired from 479 beef carcasses to compare the ability of SSF and WBSF of 1.27-cm-diameter cores to predict TSP tenderness ratings. Slic e shear force was more strongly correlated with sensory panel tenderness ra ting than was WBSF (r = -.82 vs -.77). In Exp. 3, longissimus steaks were a cquired from 110 beef carcasses to evaluate the repeatability (.91) of SSF over a broad range of tenderness. Slice shear force is a more rapid, more a ccurate, and technically less difficult technique than WBSF. Use of the SSF technique could facilitate the collection of more accurate data and should allow the detection of treatment differences with reduced numbers of obser vations and reduced time requirements, thereby reducing research costs.