Abstract
The studies were conducted to determine the effects of preservatives such as sodium chloride, sodium nitrite, sodium benzoate and sorbic acid on the survival of L. monocytogenes with regard to interaction of temperature, heat and pH of the medium. Inactivation of L. monocytogenes Scott A was more predominent by combination of sodium chloride and the other preservatives than sodium chloride alone, and inactivation was more exhilarated at $4^{\circ}C$ than at $35${\circ}C.$ The organism was not inactivated when sodium chloride, sodium nitrite, sodium benzoate and sorbic acid were added to 3%, 100ppm, 0.1, or lower, respectively, but was inactivated in the concentration increased twice. In TSB(tryptic soy broth) at pH 5.0 or lower, the organism did not grow regadless of the kinds of preservatives, and inactivation effect particularly was prominent in the presence of sodium nitrite and sorbic acid. On the other hand, at pH 6.0 or higher L. monocytogenes gradually increased in numbers and the effects of inhibition was higher in the presence of sorbic acid than in the other preservatives. When the preservatives were added to the concentration commonly used, incubation in TSB at $4^{\circ}C$ gradually resulted in growth of the bacterium and the organism rapidly decreased in numbers at $20^{\circ}C\; or\; 35^{\circ}C$ after incubation for 1 week. When L. monocytogenes was inoculated in TSB containing various preservatives and heated at $55^{\circ}C$ for 30minutes, the organism decreased in numbers at all preservatives. Particularly, viability rate of the organism was the lowest as 0.07% in the presence of sorbic acid.