Incidence and sensory evaluation of injection-site lesions in beef top sirloin butts.

The effects of ongoing quality assurance initiatives on the national incidence of injection-site lesions and the impact of these lesions on the sensory characteristics of top sirloin butts were examined by a series of audits and two experiments. The national incidence of injection-site lesions in top sirloin butts (n = 98,192) has not changed between July 1993 (10.91%) and July 1995 (10.19%). However, during this same period, the mean weight of injection-site lesion trim increased (P < .05) from 102.63 +/- 12.56 g to 152.81 +/- 13.24 g. Eighty percent of lesions examined during this period were classified as chronologically "older," originating from injections given either during preweaning, stocking, or in the early feeding period; however, there was an increase (P < .01) in the incidence of nodular scars during the audit period, likely created by intramuscular injections during the mid- to late-feeding periods. Warner-Bratzler shear measurements of lesion-afflicted steaks taken near the site of lesions and in areas up to 7.62 cm from the lesion center were significantly greater than similar measurements on control top sirloin steaks. Panelist tenderness scores for mildly lesioned steaks were lower (P < .05) and had greater within-(P < .01) and among- (P < .05) steak variation than control (normal) steaks. Mean juiciness ratings were higher (P < .001) for lesioned steaks; however, steak flavor intensity variation was greater within injection-site lesioned vs control top sirloin steaks, with undesirable flavors reported by panelists. Injection-site lesions still occur at an unacceptable frequency in the top sirloin butt, and those lesions, if not removed entirely, can dramatically reduce the desirability of top sirloin steaks.