Growth inhibitory effect of bacteriophages isolated from western and southern coastal areas of Korea against Vibrio parahaemolyticus in Manila clams

Abstract

Vibrio parahaemolyticus is one of the leading causes of seafood-related illnesses in Korea and the whole world. The growth inhibitory effect of V. parahaemolyticus-specific phages (Vpp) in clam samples was investigated. Six bacteriophages specific to V. parahaemolyticus were isolated by the agar overlay method using sediment and seafood samples from the western and southern coastal areas of Korea. Host range, restriction digestion pattern, and transmission electron microscope images of phage isolates were examined. The most effective phage, Vpp2, at a multiplicity of infection (MOI) of 10 showed 4.2 log CFU/mL reduction in V. parahaemolyticus growth at 30 °C and 6 log CFU/mL reduction after the incubation at 37 °C for 6 h. In a food application study, Vpp2 at an MOI of 100 demonstrated a 2.1 log CFU/mL reduction at 25 °C after a 24-h incubation in shell-less Manila clams spiked with V. parahaemolyticus. Additional studies are needed to characterize the newly discovered Vpp and their potential applications as biocontrol agents in food.