Production and characterization of a monoclonal antibody against recombinant thermolabile hemolysin and its application to screen for Vibrio parahaemolyticus contamination in raw seafood

Thermolabile hemolysin gene (tlh) is regarded as a species-specific marker for Vibrio parahaemolyticus. To assess the utility of the tlh gene product, thermolabile hemolysin (TLH), as a marker to screen for V. parahaemolyticus-contamination in raw seafood, we generated a monoclonal antibody (MAb) against recombinant TLH and established with an enzyme-linked immunosorbent assay using the MAb (TLH-ELISA). TLH-ELISA testing of broth cultures for 78 V. parahaemolyticus strains showed positive results all around. In contrast, most broth cultures of 53 non-V. parahaemolyticus species tested yielded negative results.We devised a screening method using TLH-ELISA to check for low-level contamination of V. parahaemolyticus in raw seafood within 24 h and evaluated its ability. In testing of V. parahaemolyticus-spiked raw seafood, results suggested that our screening method can detect 100 most-probable-number (MPN) of V. parahaemolyticus/g. Further, on testing 119 commercial raw seafood samples with our screening method, 117 samples were determined to contain less than 100 MPN of V. parahaemolyticus/g. All of the 117 samples were also estimated by the MPN method to contain less than 100 MPN of V. parahaemolyticus/g. Taken together, these results suggest that our screening method using TLH-ELISA is useful to check for low-level (<100 MPN/g) of V. parahaemolyticus in raw seafood.