Food products, such as precooked meats, sausages, and the like are microbially decontaminated in their cooking packages to remove surface microorganism contamination from the packages. The cooking packages are removed and the food products optionally subjected to further processing, such as slicing, and then packaged in aseptic packaging. The microbial decontamination step, further processing and packaging are carried out in a clean room which is maintained to a high level of sterilization or disinfection to minimize or eliminate contamination of the food products with pathogenic microorganisms such as Listeria Monocytogenes. The food products thus leave the packaging plant with a much higher assurance of food safety than is found in a conventional packaging plant.