Nisin in cheese production

Nisin, also known as lacticin, is a natural polypeptide antibiotic produced by the fermentation of Streptococcus lactis. It effectively addresses the problem of thermophilic bacteria contamination in cheese production, with specific performances as follows:

Inhibiting the growth and reproduction of thermophilic bacteria: During cheese processing, even after high-temperature sterilization, spores of heat-resistant Gram-positive bacteria may still survive, such as Clostridium botulinum and anaerobic clostridial spores. Nisin can effectively prevent the germination of these spores and the formation of toxins, and completely inhibit the germination and reproduction of spores of Bacillus and Clostridium species, thereby reducing cheese spoilage caused by thermophilic bacteria contamination.

Enhancing bactericidal effect: Nisin can increase the heat sensitivity of some bacteria and has an auxiliary bactericidal effect within a small range. Therefore, using nisin in cheese production can reduce sterilization temperature and shorten sterilization time. While ensuring the bactericidal effect, it can better maintain the color and flavor of cheese and reduce the loss of nutrients.

Extending product shelf life: Due to its inhibitory effect on thermophilic bacteria, adding nisin to cheese can make up for the shortcomings of low-temperature sterilization, effectively extend the shelf life of cheese, reduce the risk of product deterioration caused by microbial contamination, and facilitate the storage and sales of cheese.

Optimizing cheese quality: Studies have shown that using nisin-producing bacteria together with other lactic acid bacteria in cheese fermentation can increase the degree of protein hydrolysis and the number of free amino acids in cheese, as well as raise the concentration of some flavor substances, improving the flavor of cheese without affecting indicators such as the pH value of cheese.

In addition, nisin has good stability under acidic conditions and can withstand high-pressure sterilization at 115.6°C without losing its activity, which allows it to better adapt to the relevant process conditions in cheese production. Generally, adding 0.05g/kg to 0.1g/kg of Nisin to cheese can achieve a good bacteriostatic effect.