Time-Temperature Conditions of Gyros

Four gyro operations in foodservice establishments were examined for the possibility that pathogenic foodborne bacteria could survive and/or grow during each step of these operations. Gyros cooked on broilers attained temperatures lethal to vegetative pathogenic bacteria on the surface of the meat and in the thin layer just below the surface, but nowhere else. However, only meat sliced from the surface was normally put in gyro sandwiches or otherwise served. The temperatures of gyros as they cooled were such that bacterial growth could occur, both on the surfaces and within the mass. After gyros had been cooked and cooled, as many as 10,000 Clostridium perfringens per gram were recovered from samples taken just under the surface. Temperatures of gyro meat during reheating varied with the method of reheating, and they were in safe ranges when slices of meat were reheated in microwave ovens and steam chambers. When gyros were reheated on broilers, however, temperatures lethal to vegetative pathogenic bacteria occurred at and near the surfaces only. Recommendations for procedures to use for cooking, slicing, hot holding, cooling, and reheating gyros to prevent this product from becoming a vehicle of foodborne illness are given. Emphasis is on using the entire gyro the day it is originally cooked, rapid cooling of any leftover portions, and thorough reheating of leftover gyros.