ABSTRACT
In recent years, there has been increased interest in the exploitation of natural microbial inhibitors such as bacteriocins for the biopreservation of food and as possible alternatives to antibiotics for medical applications. Owing to the success of the lantibiotic bacteriocin nisin as a biopreservative in food applications, interest in the potential use of other bacteriocins has increased considerably. Lantibiotics represent a class of bacteriocins that are extensively modified posttranslationally, resulting in the biologically active moiety. Members of the group include nisin, epidermin, gallidermin, Pep5, mersacidin, and actagardine, as well as the duramycin-type lantibiotics. Undoubtedly, the most fully documented and well characterized of the lantibiotics is nisin, which was discovered in 1928 by Rogers and Whittier (1) and is now approved in over 40 countries worldwide for use in a variety of food applications. There are a number of features associated with nisin that make it very attractive for such applications. The bacteriocin has a broad target range and kills a wide spectrum of gram-positive bacteria including food pathogens such as Listeria monocytogenes and spoilage bacteria such as Clostridium species. Nisin is produced by the food grade bacterium Lactococcus lactis subsp. lactis, a strain commonly used in cheesemaking, and thus can be directly introduced into some products simply by using nisin-producing starters. Furthermore, nisin-producing strains occur naturally in raw milk. Nisin is commonly used as a preservative in processed cheese and cheese spreads in the United States, for which it has Food and Drug Administration (FDA) approval (2).
