Thermal Destruction of Escherichia coli O157:H7 in Hamburger†

The inactivation of E. coli O157:H7 in ground beef patties cooked in a skillet was investigated. Ground beef patties inoculated with a mixture of five strains of E. coli O157:H7 were cooked in a Farberware skillet set at a temperature of 275°F (137°C). Eight type K thermocouples connected to a data logger were used to record the temperatures at eight points within the patty. The cooking times studied ranged from 2.25 min to 4 min. Tryptic soy agar plates overlaid with sorbitol MacConkey agar were used for recovery of E. coli O157:H7. Heating of ground beef patties to an internal temperature endpoint of 155°F (68.3°C) resulted in 4-log cycle reductions of the organism. The results of this investigation conducted under conditions simulating those that occur in the retail food industry provide a basis for ensuring safety against E. coli O157:H7 in ground beef patties.