INCIDENCE AND SENSORY EVALUATION OF INJECTION-SITE LESIONS IN BEEF TOP SIRLOIN BUTTS

The effects of ongoing quality assurance initiatives on the national i ncidence of injection-site lesions and the impact of these lesions on. the sensory characteristics of top sirloin butts were examined by a s eries of audits and two experiments. The national incidence of injecti on-site lesions in top sirloin butts (n = 98,192) has not changed betw een July 1993 (10.91%) and July 1995 (10.19%). However, during this sa me 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 o f lesions examined during this period were classified as chronological ly ''older,'' originating from injections given either during preweani ng, stocking, or in the early feeding period; however, there was an in crease (P < .01) in the incidence of nodular scars during the audit pe riod, likely created by intramuscular injections during the mid- to la te-feeding periods. Warner-Bratzler shear measurements of lesion-affli cted steaks taken near the site of lesions and in areas up to 7.62 cm from the lesion center were significantly greater than similar measure ments on control top sirloin steaks. Panelist tenderness scores for mi ldly 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; h owever, 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 unacce ptable frequency in the top sirloin butt, and those lesions, if not re moved entirely, can dramatically reduce the desirability of top sirloi n steaks.