Effects of selected cooking procedures on the survival of Escherichia coli O157:H7 in inoculated steaks cooked on a hot plate or gas barbecue grill.
Beef steaks (2 cm thick) were each inoculated at three sites in the central plane with Escherichia coli O157:H7 at 5.9 ± 0.3 log CFU per site. Temperatures at steak centers were monitored during cooking on a hot plate or the grill of a gas barbeque. Steaks were cooked in groups of five using the same procedures and cooking each steak to the same temperature, and surviving E. coli O157:H7 at each site was enumerated. When steaks cooked on the hot plate were turned over every 2 or 4 min during cooking to between 56 and 62°C, no E. coli O157:H7 was recovered from steaks cooked to ≥58 or 62°C, respectively. When steaks were cooked to ≤71°C and turned over once during cooking, E. coli O157:H7 was recovered from steaks in groups turned over after ≤8 min but not from steaks turned over after 10 or 12 min. E. coli O157:H7 was recovered in similar numbers from steaks that were not held or were held for 3 min after cooking when steaks were turned over once after 4 or 6 min during cooking. When steaks were cooked on the grill with the barbeque lid open and turned over every 2 or 4 min during cooking to 63 or 56°C, E. coli O157:H7 was recovered from only those steaks turned over at 4-min intervals and cooked to 56°C. E. coli O157:H7 was recovered from some steaks turned over once during cooking on the grill and held or not held after cooking to 63°C. E. coli O157:H7 was not recovered from steaks turned over after 4 min during cooking to 60°C on the grill with the barbeque lid closed or when the lid was closed after 6 min. Apparently, the microbiological safety of mechanically tenderized steaks can be assured by turning steaks over at intervals of about 2 min during cooking to ≥60°C in an open skillet or on a barbecue grill. When steaks are turned over only once during cooking to ≥60°C, microbiological safety may be assured by covering the skillet or grill with a lid during at least the final minutes of cooking.
Agriculture and Agri-Food Canada Lacombe Research Centre, 6000 C & E Trail, Lacombe, Alberta, Canada T4L 1W1. colin.gill@agr.gc.ca.
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Gill
Agriculture and Agri-Food Canada Lacombe Research Centre, 6000 C & E Trail, Lacombe, Alberta, Canada T4L 1W1.
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Devos
Agriculture and Agri-Food Canada Lacombe Research Centre, 6000 C & E Trail, Lacombe, Alberta, Canada T4L 1W1, Department of Food Hygiene and Control, Cairo University, Giza, Egypt.
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Youssef
Agriculture and Agri-Food Canada Lacombe Research Centre, 6000 C & E Trail, Lacombe, Alberta, Canada T4L 1W1.
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Yang
D000818:Animals; D002417:Cattle; D003296:Cooking / Q000295:instrumentation / Q000379:methods*; D019453:Escherichia coli O157 / Q000737:chemistry / Q000254:growth & development*; D005516:Food Microbiology; D006358:Hot Temperature; D006801:Humans; D008460:Meat / Q000382:microbiology*; D050296:Microbial Viability