MICROBIOLOGICAL CONDITION OF RESTRUCTURED STEAKS PREPARED FROM PRERIGOR AND POSTRIGOR BEEF

In two experiments the microbiological quality of restructured steaks prepared from hot and cold boned beef was investigated. Half of each electrically stimulated carcass was hot boned (ca. 45 min postmortem), and the other side was deboned after 20-24 h chilling. For both experiments, defatted desinewed neck and flank muscles were flaked, and 1% NaCl was added to half of the meat batches. In experiment 1, meat batches were stored at -40-degrees-C for ca. 1 month, then tempered, restructured into steaks and refrozen. In experiment 2, restructuring of the hot boned meat followed the flaking process, then steaks were stored at -40-degrees-C. After thawing, steaks were stored at 1 +/- 1-degrees-C until sampled. Sampling occurred after 1, 4, 8, 11 and 15 d in experiment 1 and after 1 and 7 d in experiment 2, and included assays for aerobic mesophilic and psychrotrophic colony counts and Enterobacteriaceae. Results of experiment 1 indicated that deboning treatment did not affect bacterial numbers significantly. Initial contamination levels were low (ca. 4 log10 CFU/g) and spoilage occurred after greater-than-or-equal-to 8 d of storage. In experiment 2, deboning treatment had a significant effect on bacterial growth. Initial (mesophilic and psychrotrophic) contamination was lower on hot processed steaks, yet after 7 d of refrigerated storage, bacterial numbers were higher (p < 0.95) on hot vs. cold boned steaks. Experiments 1 and 2 showed that salt did not affect bacterial growth.