Nisi n, this polypeptide antibiotic, exhibited bactericidal activity when tested against bacteria at low Concentration in the medium of pH=5.5. At the higher PH values higher concentration of nisin were needed. Moreover, it was shown that to kill all bacterial cells in medium, concentration of nisin must be sufficient. Our studies indicated that, when nisin used in combination of nitrite against L.monocytogenes, it reduced the concentration of nitrite needed for the eradication of bacteria, even lower than the standard sally and p remissible value (200 ppm) . In the acid conditions the amount of nitrite plus nisin— sufficient to kill bacteria, reduced markedly.
This preliminary experiments showed that nisin in combination of nitrite can be used as a reliable and promising food preservative.