Survival of Vibrio parahaemolyticus in presence of chlorine.

Vibrio parahaemolyticus is known to be a causative agent of gastroenteritis associated with seafood consumption. The concn. and contact time required by hypochlorite for killing/reducing cells of V. parahaemolyticus in phosphate buffered saline (PBS) and in association with fish (lesser sardine; Esculosa thoracata) was studied. A min. level of 0.5 p.p.m. of available chlorine was able to reduce the count of both Kanagawa positive (K+) and Kanagawa negative (K-) V. parahaemolyticus in PBS by 90% within 5 min; complete killing of both strains was achieved in 20 and 30 min, respectively. In fish artificially contaminated with K+ V. parahaemolyticus and exposed to 10 and 20 p.p.m. available chlorine, complete destruction of cells was observed in 10 min; at 30 p.p.m., the time required was only 5 min. Haemolytic activity of the K + V. parahaemolyticus was not affected by chlorine treatment. It is concluded that chlorinated water should be routinely employed as a disinfectant in sea food processing establishments to reduce risks of pathogen contamination.