Nisin is a bacteriocin produced from strains of Lactococcus Lactis, subspecies lactis and cremoris.
Bacteriocins are substances of a protein nature synthesized by some bacteria with the aim of hindering the growth of other microorganisms in the same environment. In particular, nisin is active against positive GRAMs (streptococci, bacilli and clostridia), while it has no activity against negative GRAMs.
Once taken, nisin is rapidly digested and inactivated by gastric and pancreatic proteases; consequently it does not negatively affect the human intestinal microflora. Its use in the industrial field mainly concerns the food sector, where it is added as a preservative (E234) in fruit juices, acid sauces (mayonnaise, ketchup), pastry creams and dairy products (it is naturally found in dairy products). Nisin, in particular, carries out its antimicrobial action at acidic pH, while it is already inactivated in conditions of slight basicity.
