The safety of Nisin in cheese production

Nisin, a natural antimicrobial peptide produced by Lactococcus lactis, has been widely used as a food preservative in the production of cheese and other dairy products. Its safety has been fully verified through long-term practice and scientific research, with specific manifestations as follows:

I. Toxicological Safety

Natural origin and human tolerance: Nisin is a polypeptide composed of 34 amino acids. Upon entering the human body, it can be rapidly degraded into amino acids by proteases in the gastrointestinal tract (such as trypsin) and does not accumulate in the body. Toxicological studies have shown that its acute toxicity is extremely low—the median lethal dose (LD₅₀) for oral intake in rats exceeds 10g/kg body weight, which is much higher than the actual dosage used in production (usually 0.025-0.2g/kg cheese). Therefore, normal intake will not cause acute toxicity to the human body.

Long-term safety and genotoxicity: Multiple long-term feeding experiments have shown that even with long-term intake of feed containing Nisin, the growth, organ function, and reproductive capacity of experimental animals remain normal. In addition, genotoxicity tests (such as the AMES test and chromosome aberration test) have not found that Nisin has mutagenic or teratogenic effects, further confirming its safety in long-term use.

II. Regulatory Recognition and Usage Restrictions

International and domestic regulatory approval: Nisin has been recognized as a safe food additive by the World Health Organization (WHO) and the Food and Agriculture Organization (FAO) (with an Acceptable Daily Intake (ADI) of 0-33000IU/kg body weight) and has been approved for use in food processing in many countries and regions, including China, the United States, and the European Union. In China, Nisin is listed in GB2760-2014 National Food Safety Standard for the Use of Food Additives, allowing appropriate use in dairy products such as cheese according to production needs, reflecting regulatory recognition of its safety.

Strict control of usage dosage: Although Nisin has high safety, its use must comply with dosage restrictions. In cheese production, the addition amount is usually adjusted according to product type and shelf-life requirements, generally not exceeding 0.2g/kg. This dosage can effectively inhibit the growth of pathogenic bacteria and spoilage bacteria such as Listeria and Staphylococcus aureus, while avoiding flavor impacts (such as a slight bitter taste) caused by excessive addition and ensuring that the total intake remains within a safe range.

III. Indirect Protection of Cheese Quality and Consumer Health

Reducing the use of other preservatives: Nisin has a high inhibitory effect on Gram-positive bacteria (especially bacilli and clostridia), effectively extending the shelf life of cheese. Its application can reduce the usage of other preservatives such as nitrites and potassium sorbate, lowering potential health risks associated with these substances (e.g., nitrosamine formation from nitrites) and indirectly improving the safety of cheese.

Maintaining the natural properties of cheese: As a natural antimicrobial peptide, Nisin is well compatible with milk components in cheese, without damaging the nutritional structure of cheese (such as proteins, fats, and vitamins) or producing harmful metabolites. Compared with chemical preservatives, it better meets consumers' demand for "natural and healthy" foods, making it particularly suitable for the production of high-end cheese and cheese edible by infants and young children.

IV. Potential Controversies and Scientific Consensus

Current controversies regarding the safety of Nisin mainly focus on sensitivity issues in some populations. A very small number of people may be allergic to it, but such cases are extremely rare, and there is no clear clinical evidence linking it to severe allergic reactions. The scientific community generally agrees that Nisin is safe for most people (including children, pregnant women, and the elderly) when used within specified dosages.

The application of Nisin in cheese production has sufficient safety basis. Its natural origin, low toxicity, regulatory approval, and positive effects on product quality make it a safe and efficient preservative in cheese processing. Within a reasonable range of use, it can effectively ensure the edible safety and shelf stability of cheese.