Research – Effect of food matrix type on growth characteristics and hemolysin production of Vibrio alginolyticus

Journal of Food Protection

Food Illness

The growth and hemolysin production of two V.   alginolyticus  strains (HY9901 and ATCC17749T) at 30 °C in briny tilapia, shrimp, scallop, oyster, pork, chicken, freshwater fish and egg fried rice were investigated. Bacterial counts were enumerated by plate counting. Hemolysin production was evaluated by blood agar and hemolytic titer tests. The two V.   alginolyticus  strains displayed similar growth and hemolysin production patterns in the foods. Based on the goodness of fit primary model statistics (R 2 , MSE, BF, AF), the modified Gompertz model was a better fit to V.   alginolyticus  growth in foods than the logistic model. Growth kinetic parameters of V.   alginolyticus  displayed a higher μ max and shorter λ in briny tilapia > shrimp > freshwater fish > egg fried rice > scallop > oyster > chicken > pork. It was notable that the V.   alginolyticus  counts were similar at the stationary phase, with no significant growth behavior difference between raw and cooked foods. Significantly higher (p < 0.05) thermostable direct hemolysin (TDH) activity was produced by V.   alginolyticus  in briny tilapia > freshwater fish > shrimp > chicken > egg fried rice > scallop > oyster > pork. But the hemolytic titer was not consistent with the TDH activity, being significantly higher (p < 0.05) in briny tilapia > egg fried rice > shrimp > freshwater fish > chicken > scallop > oyster > pork. Contrary to current belief, V.   alginolyticus  displayed a higher hemolysin production in some non-seafoods (freshwater fish, egg fried rice and chicken) than in scallop or oyster. This is the first report of growth and toxicity of V. alginolyticus  in different food matrices and confirmation that some non-seafood contaminated with V. alginolyticus  can be even more pathogenic. This study will enhance the awareness of non-seafood safety and improve the V.   alginolyticus  risk assessment accuracy.

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