4 packaging and the microbial shelf life of food - ….pdfVIP

4 Packaging and the Microbial Shelf Life of Food Dong Sun Lee Department of Food Science and Biotechnology Kyungnam University Masan, South Korea CONTENTS 4.1 Introduction 55 4.2 Dei nition of Parameters and Terms for Microbial Shelf Life 56 4.3 Intrinsic and Extrinsic Factors Affecting Microbial Growth 58 4.3.1 Intrinsic Factors 59 4.3.2 Extrinsic Factors 60 4.4 Food Factors and Microbial Ecology Inl uenced by Packaging 64 4.5 Effect of Package Gas Barrier on Microbial Shelf Life 67 4.6 Modii ed Atmosphere Packaging to Extend Microbial Shelf Life 70 4.7 Packaging Tools to Monitor Microbial Shelf Life 73 4.8 Conclusions and Prospects 74 4.1 INTRODUCTION 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 iso- lating 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 modii cation, and active packaging. These variables affect the microbial l ora in the food, the spoil- age rate due to organisms of concern, and the time for the food to become microbiologically unac- ceptable. 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 modii ed atmosphere packaging (MAP) on mic