INFLUENCE OF PRESLAUGHTER STUNNING ON TURKEY BREAST MUSCLE QUALITY

Pectoralis muscle quality was evaluated from 18-wk-old tom turkeys aft er electrical stun, carbon dioxide stun, or no stun methods were appli ed. Color was measured on raw muscle and cooked meat using a colorimet er. Muscle pH was measured 15 min postmortem (initial), 24 h post-mort em (final), and after cooking. The right Pectoralis muscle of each car cass was excised for m-calpain analysis within 4 min postmortem. After 24 h of storage at 4 C, the left Pectoralis muscle was excised to det ermine cook loss and shear force measurements. No significant differen ce was found in initial muscle pH (15 min) from turkeys receiving elec trical or carbon dioxide stunning, 6.36 +/- 0.15 and 6.20 +/- 0.14, re spectively. However, initial muscle pH for birds that were not stunned (5.99 +/- 0.08) was lower (P < 0.05) than the muscle pH of birds stun ned using either of the two stunning methods. Stunning method had no e ffect on the final muscle pH, raw muscle color, cooked meat pH, cooked meat color, cook loss, or shear force. Cook loss was found to positiv ely correlate with initial muscle Lightness (r = 0.53), and cooked mea t lightness (r = 0.48), but to negatively correlate with cooked meat y ellowness (r = -0.48) and shear strength (r = -0.43), m-Calpain activi ty declined with the stunning methods in the following order: electric al > carbon dioxide > no stun. In addition, m-calpain activity was fou nd to correlate with initial muscle pH (r = 0.95) and with cooked meat shear force (r = -0.43). The results of this study show that electric al stunning, carbon dioxide stunning, and no stunning methods provide comparable cooked turkey breast meat quality with no consistent differ ences after aging on the carcass for 24 h.