ACID RESISTANCE AND INFECTIVITY OF FOOD-POISONING CLOSTRIDIUM PERFRINGENS

Abstract

Cells of food-poisoning Clostridium perfringens were subjected to treatment with synthetic gastric fluid. The log₁₀survival of the cells followed a descending convex curve, both with duration of treatment and with decreasing pH. Resistance was at a minimum during the early logarithmic phase and increased to a maximum at the end of the growth phase by a factor of 10,000. Cells at stages of relatively high resistance consistently and effectively produced the food-poisoning syndrome in human volunteers while cells at stages of low resistance produced only mild abdominal discomfort.The transient changes in resistance to simulated gastric fluid in the presence and absence of pepsin were basically the same, but pepsin and other proteins had a protective effect on the cells during acid treatment.