Hot-Fat Trimming Effects on the Microbiological Quality of Beef Carcasses and Subprimals

Subcutaneous and kidney-pelvic-heart fat were trimmed from one side of each beef carcass (n = 9) immediately after cold water washing. Both sides were sampled for aerobic plate counts (APCs) before being moved to the chill room (0 h) and after 72 h of cold storage. The mean APCs (log₁₀ colony-forming units (CFU)/cm²) of trimmed (HFT) sides at 0 or 72 h were not different (P > 0.05) from those of the nontrimmed (NFT) sides. All sides at 72 h had reduced microbial counts compared to 0 h. By 72 h, HFT sides had numerically lower counts than NFT sides, indicating that the microbial reduction effect of the chill temperature may have been greater on fat-trimmed carcasses than on nontrimmed carcasses. Subprimals from HFT and NFT sides that were trimmed to 0.64-cm fat thickness were microbiologically analyzed before (0 days) and after (14 days) vacuum storage. APCs of all subprimals were slightly reduced after 14 d; however, no difference (P > 0.05) occurred in treatment effect. The mean APC was higher for HFT-side subprimals than for NFT-side subprimals at both 0 and 14 days. This difference probably was due to the fat trimming required for NFT-side subprimals at day 0 as compared to minimal or no trimming of HFT-side subprimals. Those HFT subprimals which were not subsequently trimmed may have picked up additional microorganisms from contact surfaces during fabrication. Based on our trimming protocol, although HFT did not show any negative impact on the microbial quality of carcasses, the higher APC of HFT-side subprimals indicated that extensive trimming may not be effective in improving the microbial quality of meat.