A large scale food poisoning occurred in September 1970 in Ogaki City, Gifu Prefecture, which involved 494 patients out of 891 persons who had taken lunches supplied from a manufacturing company.
This outbreak of food poisoning was considered to be caused by heat-resistant
Clostridium perfringens which had presumably contaminated the Chinese cabbage in the lunches by the following reasons:
1. In most of the patients incubation periods were within 15hr after taking the lunches.
2. The main symptoms were diarrhea, abdominal pain, and nausea without vomiting. All patients recovered within 2 days.
3. In the bacteriological investigation of rectal swabs
C. perfringens were isolated from 15 out of 21 patients and from 5 out of 14 cooks. The isolates appeared to be a typical strains of the classical type A strains with respect to the differences in toxicity for mice, heat resistance and hemolytic activity for the horse red blood cells.
4. All the isolates were found to have the same biological and physiological properties. These strains were slightly more sensitive to kanamycin than those from other origins.
5. When several strains of
C. perfringens were experimentally inoculated to chinese cabbages prepared in the laboratory, the number of organisms increased significantly after incubation of 17hr at 30°C.
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