ABSTRACT
Most preservation techniques act by method, preventing or retarding microbial growth, e.g., by freezing, chilling, drying, curing, conserving, vacuum packing, modified-atmosphere packing, acidifying, fermenting, or adding preservatives. Antimicrobial systems that occur naturally—produced by animals, plants, and microorganisms—mostly act by inactivation. Numerous highly effective antimicrobial systems operate in animals. They include the immune system in higher animals and a number of bacteriolytic and other enzymes that are components of bactericidal systems as well as some nonenzymatic proteins with antimicrobial activity. Hen egg white lysozyme is the most readily and economically available muramidase and therefore finds application to inactivate microorganisms in foods. The iron-binding glycoprotein from eggs and the analogous protein from milk have received attention as potential food preservatives because they have a broad spectrum of activity and are present at high concentrations. Lactoferricin is an antimicrobial polypeptide that can be derived from lactoferrin by limited acid hydrolysis or proteolysis.
