Evaluation of the reduction of e. coli in beef strip loins, ribeye rolls, and top rounds at temperatures lower than 54.4c

The study evaluated the reduction of Escherichia coliin strip loins, top rounds and ribeye rolls cooked to internal temperatures of 54.4°C or lower.A cocktail of five strains of Escherichia coli(ATCC®BAA-1427, 1428, 1429, 1430, 1431)was utilized (surrogates for Salmonella). Meat was dip in oculated with E.colito achieve a 7.5-log10CFU per gram inoculation level on the meat. The combination of temperatures and times held were 54.4°Cfor 2 and 3 h, 51.7°C for 3 and 5 h, and 48.9°C for 10 and 12 h. Samples were enumerated on MacConkeyAgar to determine E. colisurvival. Data (3 replications / 2 samples per replication) were analyzed using Excel and the GLM procedure of SAS to determine the average reduction of E. coli.Strip loins had a 6.5-log10reduction at 54.4°C when held at both 2 and 3 h; a reduction of 5.5-log10reduction when held for 3 hand a 6-log10 reduction when held for 5 hat 51.7°C, and at a temperature of 48.9°C held for 10 hresulted in a 5.7-log10reduction and held for 12 hachieved a5.3-log10reduction. Ribeye rolls had a 6.3-log10reduction at 54.4°C when held for2 hand a 6.5-log10 reduction when held for 3 h,51.7°C resulted in a6.08-log10reduction when held for 3 hand a 5.43-log10 reduction when held for 5 h, and 48.9°C resulted ina 5.3-log10 reduction when held for 5 hand when held for 12 h achieved a 6.1-log10 reduction. All top round temperature/time relationships resulted in less than a 5-log10 reduction. Results suggest that lower temperatures could possibly achieve a 6.5-log10 reduction in accordance with Appendix A if the product was held at the temperature for the correct time in a cook-in bag.