scope:

This Technical Specification specifies a method for the quantitative determination of the nisin A content in cheese.

The method is suitable for measuring low levels of nisin A with a quantification limit of 1 mg/kg.

NOTE Nisin is a peptide produced by some bacteria (e.g. Lactococcus lactis subsp. Lactis) inhibiting or destroying other microorganisms. It is widely used as a natural preservative for foods, e.g. vegetables, cheese, meat, and cacao. In cheese making, nisin is used to prevent late blowing. Its use is restricted to maximum levels in the final product. Nisin appears in two forms, nisin A and nisin Z, which differ in one amino acid. This method is applicable to the determination of nisin A only.