Utilization of Temperatures Lower Than 54.4°C to Evaluate the Reduction of Salmonella Surrogate, Enterococcus Faecium ATCC 8459, In Beef Prime Rib Roasts

The reduction of Salmonella surrogate, Enterococcus faecium ATCC 8459, was evaluated in strip loins and ribeye rolls at internal temperatures lower than 54.4°C, to determine if a 6.5-log10 reduction could be achieved, as required by USDA-FSIS and demonstrated in Appendix A. Ninety strip loins (SL) and 90 ribeye rolls (RR) were inoculated with 10 mL of inoculum each. The initial inoculation results with E. faecium ATCC 8459 had a mean of 6.14-log10 on ribeye rolls and strip loins had a mean of 5.23-log10. Roasts were cooked to internal temperature treatments of 54.4°C for 121 min and 4 h, 51.7°C for 4 and 6 h, and 48.9°C for 15 and 18 h. Results were analyzed utilizing the PROC GLM, LSMEANS, PDIFF and STDERR functions of SAS. Strip loins held at 48.9°C for 15 h had a mean reduction of 0.83-log10 and at 18 h a 1.22-log10 reduction. At 51.7°C for 4 h SL had a mean reduction of 0.93-log10 and at 6 h a 0.87-log10 reduction. At 54.4°C for 121 min SL had a mean reduction of 0.87-log10 and at 4 h a 1.14-log10 reduction. Ribeye rolls held at 48.9°C for 15 h had a mean reduction of 1.09-log10 and at 18 h a 2.04-log10 reduction. At 51.7°C for 4 h RR had a mean reduction of 0.91-log10 and at 6 h a 0.90-log10 reduction. At 54.4°C for 121 min RR had a mean reduction of 2.64-log10 and at 4 h a 2.78-log10 reduction. Results suggest that lower temperatures are not sufficient to achieve a 6.5-log10 reduction as required by the USDA-FSIS.