Survival of bacteria in artificially contaminated frozen meat pies after baking.

The tremendous growth of the frozen food industry during the past decade has resulted in the advocation of bacteriological standards for frozen foods by certain agencies. Some frozen food plants already have selfimposed bacteriological standards and quality control functions. To help complete the picture on the microbiology of frozen foods before bacteriological standards are imposed, information should be acquired regarding the survival of bacteria in precooked frozen foods after baking. There have been several reports in the literature concerning the numbers and the species of bacteria which were encountered in unbaked frozen meat pies by Larkin, Litsky, and Fuller (1955), Canale and Ordal (1957), Litsky, Fagerson, and Fellers (1957), Huber, Zaborowski, and Rayman (1958), Ross and Thatcher (1958), and Kereluk and Gunderson (1959). However, there is little information concerning the effect of baking on the microbial flora of frozen meat pies. Studies by Canale and Ordal (1957) on frozen poultry pies have indicated that some of the times and temperatures recommended by the manufacturers are not sufficient to eliminate the nonsporeforming organism. It was also found that the center of the pies baked, under what the authors assumed to be home conditions, did not reach a temperature high enough to reduce the bacterial count satisfactorily. Coliforms, as well as other nonsporeformers, were detected in the baked pies. Ross and Thatcher (1958) in a study of the bacteriological content of marketed precooked frozen foods in relation to possible public health hazard have shown that there is a 57.5 to 100 per cent reduction in the number of organisms found by the standard plate count after baking. However, the data presented on the effect of baking on the microbial population was limited to only a determination of the total number of bacteria. The purpose of this investigation was to determine the effect of baking on the number of viable bacteria