High-Quality Nisin for Food

Nisin, also known as Lactococcus lactis, is often regarded as the nemesis of Gram-positive bacteria. It consists of 34 amino acids with a molecular formula of C143H228O37N42S7 and a molecular weight of 3354.07 g/mol. Its molecular structure includes five rare amino acids, forming five internal rings through thioether bonds. The active molecule is often a dimer or tetramer. Nisin is a natural bioactive antimicrobial peptide, a pure, natural, efficient, and safe polypeptide active substance extracted from Lactococcus lactis using biotechnology. There are six types of Nisin molecules, among which Nisin A and Nisin Z are the most actively studied. The difference between them lies in the type of amino acid at position 27, with Nisin Z generally having better solubility and antimicrobial activity than Nisin A.

Nisin has a strong inhibitory effect on many Gram-positive bacteria, including food spoilage bacteria and pathogens. It can effectively kill or inhibit bacteria such as Lactobacillus, Clostridium, Staphylococcus, Listeria, heat-resistant spoilage bacteria, Corynebacterium, Micrococcus, Leuconostoc, and Mycobacterium.

Nisin adsorbs onto the cell membrane of Gram-positive sensitive bacteria and interacts with negatively charged substances in the cell wall (such as teichoic acids, uronic acids, acidic polysaccharides, or phospholipids). Through the action of the C-terminus, it penetrates the cell membrane, forming permeable pores, inhibiting cell wall synthesis, altering cell membrane permeability, and leading to cell autolysis and death.

At a concentration of 100 ppm, Nisin can kill most Gram-positive bacteria and is extremely sensitive to spores of thermophilic Bacillus stearothermophilus in the genus Bacillus, killing spores with minimal amounts.

Due to its potent inhibitory effect on Gram-positive bacteria, Nisin is widely used for the preservation of dairy products, canned foods, convenience foods, and more. In dairy products, it can extend the shelf life of pasteurized milk, skim milk, sugar-free condensed milk, UHT milk, flavored milk, canned milk desserts, cream products, and reconstituted milk products from milk powder.

Nisin is a natural preservative that is quickly digested into amino acids by proteolytic enzymes in the digestive tract after consumption. It does not alter the normal intestinal flora, does not cause antibiotic resistance issues, and does not show cross-resistance with other antibiotics. Toxicological tests in various countries have proven it to be safe and non-toxic.

In summary, Nisin, with its natural, efficient, and safe characteristics, along with its strong inhibitory effect on Gram-positive bacteria, can indeed be called the nemesis of Gram-positive bacteria. In the food industry, it has become an important preservative, providing strong protection for food safety and preservation.