Food and beverage spoilage has been a problem throughout history. Most food spoilage is due to
enzyme action upon food. Enzymes are complex organic compounds that may act as catalysts and
cause a chemical change to occur. Most enzymes that cause food to spoil are produced by living
organisms, e.g., bacteria, molds and yeast. Fresh foodstuffs may have some of these microorganisms
present and others may be encountered by exposure to the air or in processing. The enzymes that
cause spoilage may be generally described as two types; “endoenzymes” which exist within the
microorganism and “exoenzymes” which are released by the microorganism. Consequently, the quality
of microorganism enzymes of both types which cause food to spoil is directly related to the
concentrations of the microorganism present, its species, and its general activity.