Enumeration of presumptive Vibrio parahaemolyticus in edible shucked shellfish by the use of most probable number technique

Enumeration of presumptive V. parahaemolyticus in shucked shellfish was made by a simple multiple tube technique with Arabinose-Colistin-Peptone-Water (ACPW). During the period June 1973-March 1975, Mactra chinensis and Scapharce broughlomii were obtained at Tokyo Central Wholesale Market. Throughout the surveys conducted on the incidence of the presumptive organism in the shellfish, it was found that when monitored mean MPN of the presumptive organism had exceeded the level of 104/g, a frequent occurrence of parahaemolyticus food poisoning patients was observed in Tokyo. Although we were unable to prove the presence of Kanagawa positive organism among our isolates, we would like to propose following preventive measures for parahaemolyticus food poisoning; 1) Adoption of a tentative guide line “less than 104/g” as an alowable limit of presumptive V. parahaemolyticus for marine products which might be consumed in a raw state; and 2) Labeling of “edible in raw” must be on the guaranteed, and prohibition of combined handling with other sort of sea products at retailers.