Modeling Vibrio parahaemolyticus inactivation by acidic electrolyzed water on cooked shrimp using response surface methodology

Vibrio parahaemolyticus is the leading cause of seafood-derived illness in China and a possible mechanism leading to illness is cross contamination of cooked shrimp. The objective of this study was to establish a mathematical model of the inactivation of V. parahaemolyticus on cooked shrimp by acidic electrolyzed water (AEW) as a function of three variables (NaCl concentration to electrolysis, X1; treatment time, X2; treatment temperature, X3) and to define priority factors which can significantly enhance the bactericidal efficiency to reduce the risk of illness caused by V. parahaemolyticus. The combined effects of NaCl concentration (0.7-2.4 g/L), treatment time (3.6-10.4 min) and temperature (23-57 °C) on Log reductions of V. parahaemolyticus on cooked shrimp were investigated according to a central composite design, and the Log reductions were modeled using a response surface model. The result showed the established RS model had a goodness of fitting quantified by the parameters of R2 (0.982), lack of fit test (p > 0.05), the root-mean-squares error (RMSE = 0.15), the accuracy factor (Af = 1.10) and bias factor (Bf = 0.99). The model was validated with additional random 8 conditions within the range of the experimental domain. It showed that the established RS model possessed a good performance and suitability approved by RMSE (0.43), Af (1.28) and Bf (1.19). Moreover, the effects of the independent variable and their interactions on response value were ranked as X3 = X32 >> X1X3 > X2 > X1 according to Pareto charts and response surface plots analysis. The present work could serve as useful tools for predicting the inactivation of V. parahaemolyticus on cooked shrimp by AEW.