ABSTRACT
Food preservation has as its goal the extension of shelf life of foods to allow storage and convenient distribution. The most dangerous source of limitation of shelf life is due to the activity of microorganisms. The first aim of food preservation is therefore to eliminate the danger of spoilage due to microbes and to avoid their health-threatening activities. Several food preservation processes have a common basis in achieving this aim by limiting the availability of water to microorganisms. These processes include concentration, dehydration, and freezing. Concentration (Chapter 9) and dehydration (Chapter 10) reduce availability of water by reducing the total water content. Freezing (Chapter 8) results in crystallization of most of the water and consequently in a much reduced water content in the unfrozen portion of the food. Other preservation processes are based on adding solutes, such as sugars or salt, which reduces water availability. The present book does not include these processes since they are not considered physical methods of preservation.
