Effects of Exercise, Electrical Stimulation and Vacuum Packaging on Bacterial Counts and Tenderness of Fresh Beef...

Two wholesale cuts, the silverside ( M biceps femoris ) and bolo, (outside round and clod) from 8 steers were used in this study. Four steers were artificially stressed and the right side of all carcasses was electrically stimulated. Primals were cut into 3 equal portions after 72 h post slaughter, chilling at approximately 4°C, and were vacuum packaged. No microbial differences (P>0.05) were found between primals within treatments. Primals from stressed carcasses had higher pH values (P<0.01) and psychrotrophic, lactobacillus, anaerobic and aerobic counts than from nonstressed carcasses. Lactobacilli did not dominate the microbial population. Electrical stimulation (ES) and the cuts used had an influence on shear force values (P<0.05). ES cuts were significantly more tender than controls. Results suggest that animals should be well rested before slaughter.