ABSTRACT
Packaging has been a key element to preserve the quality of foods in microbiological terms. Thermal preservation became possible with the availability of retortable packaging (initially champagne bottles, then metal containers, and now multilayer plastic pouches). Aseptic packaging relies on isolating the sterilized food inside barrier packaging that has been decontaminated of microorganisms. Dry food products are protected from microbial spoilage by the barrier properties of the package, which prevent moisture transfer into the food. The shelf life of microbiologically perishable foods depends greatly on packaging variables such as gas and water vapor barrier properties, atmosphere modifi cation, and active packaging. These variables affect the microbial fl ora in the food, the spoilage rate due to organisms of concern, and the time for the food to become microbiologically unacceptable. This chapter discusses the shelf life characteristics of perishable foods in relation to the packaging variables, with an emphasis on the effects of package barrier properties and modifi ed atmosphere packaging (MAP) on microbial shelf life.
