Nisin is a natural antimicrobial peptide produced by certain strains of the bacterium Lactococcus lactis. It is commonly used as a food preservative due to its ability to inhibit the growth of various harmful bacteria, including Listeria monocytogenes and Staphylococcus aureus. Nisin is particularly effective in dairy products and canned foods, helping to extend their shelf life. As a member of the class of compounds known as lantibiotics, nisin is unique because it can disrupt bacterial cell membranes. This property makes it valuable not only in food preservation but also in potential medical applications, such as treating infections and enhancing food safety.