SAMPLING, COOKING, AND GORING EFFECTS ON WARNER-BRATZLER SHEAR FORCE VALUES IN BEEF

A series of experiments was conducted to determine the effects of vari ous factors on Warner-Bratzler shear force measurement of cooked beef. As the extent of thawing of frozen steaks before cooking for shear fo rce evaluation increases (-2 vs 12 degrees C), shear force decreases ( P <.05; 7.34 vs 5.99 kg). Location within the longissimus thoracis et lumborum from which steaks were obtained (caudal, medial, or cranial) did not affect(P >.05) shear force (5.21, 5.15, or 5.26 kg, respective ly) or any sensory trait. Mean shear force of longissimus steaks cooke d to either a constant temperature of 70 degrees C (6.97 kg) or for a constant time of 30 min (6.38 kg) was not different (P = .06), but she ar force repeatability was higher for steaks cooked to constant temper ature (.79 vs .53). Mean shear force (6.20 vs 6.33 kg) and shear force repeatability (.74 vs .68) of longissimus steaks cooked by either ele ctric broiler or convection oven broiler, respectively, were not diffe rent(P >.05). Meat cores obtained perpendicular to the steak surface, from one location within the muscle, had lower (P <.05) mean shear for ce (3.41 vs 4.17 kg) and much less repeatable shear force (.12 vs .66) than cores obtained parallel to muscle fiber orientation. Use of more than five cores per animal did not significantly increase repeatabili ty of mean shear force. Numerous factors must be carefully controlled to ensure measurement of shear force is as accurate and repeatable as possible.