Food & Cooking
Preserving food is more than an art; it is a science. Scientists and home economists have established that certain procedures are essential for a given food to make it safe, as well as retain its color, flavor, texture and nutrients. Standard recipes are designed with these research findings in mind and, when carefully followed, insure both a high-quality and a safe product.
Food is preserved by using methods that destroy or hinder the growth of microorganisms, such as molds, yeast and bacteria. These organisms may be present in the soil, on the food, in the air, on equipment or on work surfaces.
Yeasts, molds and bacteria must be destroyed during processing to prevent the food from spoiling. The correct amount of time to process varies with the kind of food. Sufficient heat for a specified length of time kills microorganisms and insures a safe product. Processing also helps to secure an airtight seal when using closures containing sealing compound.
Preventing enzymatic changes in food is another concern when preserving food. Enzymes are chemical substances found in all animals and plants. These enzymes aid in the maturing and ripening processes. If not destroyed or inactivated, enzymes cause changes in color, flavor and texture. In the canning process, enzymes are destroyed by heat.
"PB724 Canning Foods," The University of Tennessee Agricultural Extension Service, PB 724-5M-6/08 E12-5315-00-031-08, http://trace.tennessee.edu/utk_agexfood/1