Inhibitory Effect of Nisin upon Various Organisms1,2

Abstract

Summary Two nisin-producing strains of Streptococcus lactis were found to vary in their ability to produce the antibiotic. In the milk medium containing 5% of nisin-broth, cell multiplication and acid production of two strains of Streptococcus thermophilus were delayed, but upon further incubation their total cell count and acid production were not affected appreciably. Nisin-broth did not inhibit three strains of S. lactis , two strains of Lactobacillus bulgaricus , two strains of S. thermophilus , a mixed lactic culture, and one strain each of Bacillus subtilis and Bacillus cereus . Nisin was not quite as inhibitory as several other antibiotics against the dairy cultures tested. Of 11 strains of Staphylococcus aureus Used, the antibiotic seemed to be active only against the coagulase-negative and weak coagulase-producing organisms. The data presented in this paper indicate that the antibiotic may be considered for use to inhibit certain staphylococci or lactic organisms. Additional work should be conducted to determine the applications of nisin and nisin-producing organisms in the dairy industry.