Evaluation of additional cooking procedures to achieve lethality microbiological performance standards for large, intact meat products

The U.S. Department of Agriculture Food Safety and Inspection Service (USDA-FSIS) has a specific lethality performance standard for ready-to-eat products. To assist meat processing establishments in meeting the performance standard, USDA-FSIS developed Appendix A, which provides guidelines for cooking temperatures, times, and relative humidity. This project determined whether the USDA-FSIS performance standards for lethality were met when using parameters other than those identified in Appendix A to cook large hams and beef inside rounds. The effects of alternative lethality parameters on the reduction of Salmonella Typhimurium and coliforms and on the toxin production of Staphylococcus aureus were evaluated. Large (9- to 12-kg) cured bone-in hams (n = 80) and large (8- to 13-kg) uncured beef inside rounds (n = 80) were used in this study. The products were subjected to 1 of 10 treatments defined by combinations of final internal product temperatures (48.9, 54.4, 60.0, 65.6, or 71.1°C) and batch oven relative humidities (50 or 90 % ). For all treatments, at least a 6.5-log reduction in Salmonella Typhimurium was achieved. The coliform counts were also substantially reduced for both hams and rounds. Across all treatments for both products, S. aureus toxin production was not detected. The relative humidity did not alter the lethality effectiveness for any of the treatments. The final internal temperatures and relative humidity combinations used in this project achieved the lethality performance standard established by USDA-FSIS for fully cooked, ready-to-eat products.