Can nisin be added to milk?

Nisin, a polypeptide produced by Streptococcus lactis, is a natural food preservative with high efficiency, non-toxicity, safety and no side effects.

Some people think that "nisin belongs to broad-spectrum sterilization" and "inhibits not only molds and yeasts, but also Gram-positive bacteria (beneficial bacteria in yogurt)." In fact, the bacteriostatic spectrum of Nisin is relatively narrow, which only inhibits Gram-positive bacteria, but has no effect on molds and yeasts.

Nisin is a natural food preservative, which can inhibit the growth and reproduction of harmful bacteria in yogurt, prevent the decay of yogurt and prolong the shelf life of the product. Because, the water activity of yogurt Aw=0.9-0.95, bacteria, molds, yeasts can grow and reproduce, and the first cause of yoghurt spoilage microorganisms is bacteria, it is the most active and most common factor, plays a leading role. Inhibiting the reproduction of bacteria can effectively prolong the shelf life of yogurt.

Yogurt contains a large number of active lactic acid bacteria, even if stored and sold in the freezer, the acidity can also increase slowly, affecting the edible quality of yogurt. If there is no cold chain support, the yogurt continues to ferment, the production of lactic acid increases, the acidity will increase excessively, and the taste will become worse. As reflected by an enterprise, due to the rise in temperature, the acidity of the finished yoghurt soared from 70 °T to 120 °T, resulting in inedibility. Nisin can inhibit the production of lactic acid, which is the metabolite of lactic acid bacteria, and effectively solve the problem of high acidity of yogurt. Here, Nisin is also an excellent quality improver.

Keyword: preservative nisin,natural food preservative,safety preservative