The Influence of Chemical Additives on the Heat Resistance of Salmonella typhimurium in Liquid Whole Egg

Abstract

SUMMARYThe heat resistance of Salmonella typhimurium in liquid whole egg at pH 5.5 and 55°C was reduced significantly by a number of chemical additives. Of these, the most effective were β‐propiolactone, ethylene oxide, and butadiene dioxide. Additional advantages of ethylene oxide and β‐propiolactone were the elimination of S. typhimurium from heavily inoculated whole‐egg slurry during storage at 0°C and a markedly increased lag phase of growth of the test organism in egg incubated at 30°C. Butadiene dioxide, although not tested at 0°C, was most effective in reducing heat resistance at pH 5.5 and 55° C, and also greatly increased the lag phase of the test organism at 30° C. Unfortunately, this latter compound is carcinogenic to mice.Acetic or lactic acid, used to lower the pH of liquid whole eggs, decreased the heat resistance of S. typhimurium more effectively than did hydrochloric acid, especially at pH 5.5 arid 6.0. Formic and propionic acids also were more effective than HCl when all were tested at pH 5.5. Differences in degree of dissociation between hydrochloric and the organic acids are thought to account, in large measure, for these observations.