Occurrence of Vibrio parahaemolyticus in oysters from Korean retail outlets

The occurrence of Vibrio parahaemolyticus in 72 samples of raw Korean oysters obtained monthly from April to December from retail outlets was monitored, and the virulence of the strains isolated from 48 oyster samples investigated. V. parahaemolyticus was isolated in oysters from May to November with the highest level in August and September. Multiplex PCR showed that none of the V. parahaemolyticus strains isolated contained the gene for thermostable direct haemolysin (tdh), although one strain was positive for TDH-related haemolysin (trh). These data can be utilized for a risk-management plan to establish Food Safety Objectives (FSO) for V. parahaemolyticus in oysters at retail outlets in Korea.