ABSTRACT

Various physical, chemical, and biologic methods have been used to prevent food spoilage by undesirable tissue changes or microbial action and thus permit food storage for extended periods. These efforts would have been self-defeating, however, if the longer shelf-life had resulted in a deterioration of the quality and wholesomeness of the preserved food. The traditional methods employed in the first half of the Twentieth Century included heat treatment (e.g. cooking, pasteurization, or canning), cold storage, deep-freezing, chemical treatment with preservatives, and biologic procedures such as fermentation.