Environmental effects on the thermal resistance of Salmonella, Escherichia coli O157:H7, and triose phosphate isomerase in ground turkey and beef

On January 6, 1999, the USDA-FSIS published their final ruling on performance standards for meat products. Lethality standards for both turkey and beef products are based on the thermal destruction of Salmonella. Processors must prove that their thermal processes are adequate in challenge studies using meat inoculated with Salmonella. Because of obvious safety and health concerns, it is not feasible to bring Salmonella into a meat processing facility. Therefore, alternative approaches to verify adequate cooking of meat in processing facilities must be identified. The objective of this study was to determine if triose phosphate isomerase (TPI) could be used as a time-temperature integrator (TTI) in turkey and beef products to verify the adequacy of any thermal process.; Except for the treatments in which phosphate was added, the z-values for TPI and S. Senftenberg were within 0.5°C of each other. For turkey products, TPI showed good potential to be a TTI. The effect of fat content in ground beef on the thermal inactivation kinetics of TPI, a Salmonella cocktail, and E. coli O157:H7 was studied. TPI was more temperature dependent than E. coli O157:H7 and the Salmonella cocktail. A mathematical model will need to be developed and tested before TPI can be used as a TTI in ground beef.