Survival of Salmonella typhimurium and Staphylococcus aureus in eggs cooked by different methods.

Shell eggs inoculated with Salmonella typhimurium and Staphylococcus aureus were cooked by recommended procedures for boiling, poaching, and frying. Except for poaching, the recommended procedures were inadequate in destroying the inoculum placed in the yolk. Boiling for 7 min was necessary for complete destruction of S. typhimurium and it took 12 min of boiling to destroy Staph. aureus. Cooking time-temperature relationship for complete kill depended on the cooking method with fried eggs. Four minutes and 70 C were needed for covered eggs, 3 min on each side at 64 C for turned over eggs, while cooking for 7.5 min at 64 C for sunnyside eggs was not sufficient for destruction of both of the test organisms. None of the test organisms could be recovered from omelets baked by the recommended procedure (86 C for 25 min). Scrambling for 1 min at 74 C was required for the complete destruction of S. typhimurium and 2 min at 78 C for Staph. aureus.