Hazard Analysis of Frozen Dinners Prepared at a Catering Establishment1

Frozen dinners prepared by a caterer were reported to have been spoiled. Microbiological testing of samples was performed, and a survey of time-temperature exposures (during preparation, storage, delivery and reheating) was conducted of procedures duplicating those at the time the spoiled food was prepared. Growth of spoilage bacteria was not inhibited by freezing a customer's week's supply of packaged meals in cardboard boxes. This growth continued during transit in a precooled insulated truck. Meals reheated in a plywood box oven (furnished by the caterer for this purpose) failed to reach lethal temperatures for vegetative mesophilic bacteria within a practicable time (90 min). Holding the meals in wire baskets or in shallow metal trays during freezing and reheating the frozen meals to 74 C (165 F) in conventional domestic ovens prevented spoilage of the meals.