Nisin is a bacteriocin produced by a group of Gram-positive bacteria that belongs to Lactococcus and Streptococcus species. In Vitro: Nisin is classified as a Type A (I) lantibiotic that is synthesized from mRNA and the translated peptide contains several unusual amino acids due to post-translational modifications. Nisin is an antimicrobial peptide produced by certain Gram-positive bacteria that include Lactococcus and Streptococcus species^[1].