It is a pure nisin product.
Nisin is a polypeptide, which is produced by Lactococcus lactis. It is a natural and very effective food preservative. Nisin has antimicrobial activity against a wide range of gram positive (+) bacteria.
It also inhibits certain strains of pathogens such as C. botulinum, S. aureus, S. haemolyticus, L. monocytogenes, B. stearothermophilus, B. subtilis and some others.