Nisin is a naturally occurring antimicrobial peptide that is commonly used as a food preservative. It is produced by certain strains of the bacteria Lactococcus lactis and has been used for centuries to help prevent spoilage of dairy products.
In addition to its use as a food preservative, nisin is sometimes added to protein powders as a natural antimicrobial agent. It has been shown to be effective against a wide range of bacteria, including some that can cause foodborne illness. This can help to extend the shelf life of the product and reduce the risk of contamination.
Nisin is generally considered safe for consumption at the levels used in food and supplement products.