Detailed Product Description

 The suitability of nisin as a food preservative arises from the
following characteristics:
A.it is non-toxic, the producer strains of L. lactis are regarded as
safe (food-grade); it is not used clinically;
B.there is no apparent cross-resistance in bacteria that may effect
antibiotic therapeutics;
C.it is quickly digested.

Nisin has been sold under the trade name of NisinPro® . NisinPro® contains approximately 2.5% nisin. The product is standardised to an activity of one million international units per gram. Throughout this article all levels of nisin are expressed as mg pure nisin per kilogram or
litre. The assay method in most common use involves measuring zones of inhibition in agar seeded with the test organism, Micrococcus lactis.

NisinPro® is an extremely stable product, showing no loss of activity over two years when stored under dry conditions in the dark, below 25°C. Nisin shows increased solubility in an acid environment and becomes less soluble as the pH increases. However, owing to the low level of nisin used in food preservation, solubility does not present a problem. Nisin solutions are most stable to autoclaving (121°C for 15 min) in the pH range 3.03.5 (<10% activity loss). At pH values below and above this range, there is marked decrease in activity (>90% loss at pH 1 or 7). Losses of activity at pasteurisation temperatures are significantly les (approximately 20% during standard processed cheese manufacture at pH 5.65.8). Food components can also protect nisin during heat processing as compared to a buffer system.

The stability of nisin in a food system during storage is dependent upon three factors: incubation temperature, length of storage and pH. Greater nisin retention occurs at lower temperatures. For instance, the manufacture of a pasteurised processed cheese spread (85105°C for 5 10 min at pH 5.65.8) results in an initial 20~30% loss, nisin retention
after 30 weeks storage being approximately 80% at 20°C, 60% at 25°C and 40% at 30°C. Thus a higher level of nisin addition will be required if storage at unusually high ambient temperature is intended.