An ecological study of Vibrio cholerae O-1 and Vibrio cholerae non O-1, with special regard to behavior in foodstuffs and living shellfish

Abstract

The growth and survival of Vibrio cholerae O-1 and Vibrio cholerae non O-1 in foodstuffs, especially in shellfish was studied in order to cast some light on the ecology of cholera epidemic.
Alteration in the number of Vibrio cholerae O-1 and Vibrio cholerae non O-1, stuck to raw fish and raw meat, drinks (cola, alkali ion drink, milk, coffee) and soy sauce was observed in a settled temperature and whether cholera had accumulated in short-necked clams in artificial sea water contaminated with Vibrio cholerae O-1 or Vibrio cholerae non O-1 was examined. In this study, the same experimental procedure was pursued concerning the different strains of cholera ; Vibrio cholerae O-1 and Vibrio cholerae non O-1.
The following results were obtained :
1) Within 24 hours, the number of Vibrio cholerae O-1 or Vibrio cholerae non O-1 stuck to raw fish or raw meat was almost invariable at 4°C, 10°C, 16°C and 30°C.
After 48 hours, the number of Vibrio cholerae O-1 or Vibrio cholerae non O-1 stuck to raw fish was invariable, though the numbers of both strains stuck to raw meat decreased. Regarding the rate of decrease, Vibrio cholerae non O-1 was slower than Vibrio cholerae O-1.
2) Vibrio cholerae O-1 and Vibrio cholerae non O-1 ceased to exist within 30 min in soy sauce of high salt concentration and within 30 min in cola and alkali ion drink of high acidity. On the other hand, Vibrio cholerae O-1 in coffee ceased to exist within 24 hours at 4°C and 16°C.
3) When short-necked clams were placed in artificial sea water contaminated with Vibrio cholerae O-1 or. Vibrio cholerae non O-1, the organisms survived and accumulated within the short-necked clams.