Purpose: Develop and validate microwave heating instructions for the destruction of Salmonella spp. in microwaveable pot-pies.
Methods: Two household microwave ovens of low (700 W) and high (1,350) power were used. For each oven, twenty-four individual temperature profiles were obtained by heating turkey pot-pies. Time to reach 73.8°C was calculated and Final microwave heating times were selected based on the best-fit distributions at 99% upper confidence level (CL) and chi-square value. A five-serovar cocktail of Salmonella spp. (ca. 7.0 log CFU/g) was used to inoculate pot pies at the geometric center (filling), crust (center or edges) and the geometrical center with two pot-pies in the oven. Standing time (3 min) was applied for pot pies with Salmonella spp. inoculated in the filling and with 2 pot pies placed in the oven to evaluate potential destruction of the pathogen. Salmonella spp. populations were enumerated and enrichment method was followed for samples with populations below the detection limit.
Results: Salmonella spp. reduction of 5.16 log CFU/g was observed following the heating time of 7.0 and 9.5 min (for high and low power ovens) following 99% CL to attain 73.8°C. However, Salmonella spp. survival was observed following the enrichment procedure. Incorporation of a 3 min standing time resulted in elimination of Salmonella spp. in the pot-pies. Minimal reduction in Salmonella spp. population was observed when two pot-pies were heated in the microwave ovens.
Significance: Salmonella spp. destruction in microwaveable pot-pies is affected by the location of the organism in the product as well as the number of samples placed in the oven. Inclusion of standing times subsequent to heating resulted in elimination of Salmonella spp. in pot-pies.