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, XI; treatment time, X-2; treatment temperature, X-3) 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 degrees 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 R-2 (0.982), lack of fit test (p > 0.05), the root-mean-squares error (RMSE = 0.15), the accuracy factor (A(f) = 1.10) and bias factor (B-f = 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), A(f) (1.28) and B-f (1.19). Moreover, the effects of the independent variable and their interactions on response value were ranked as X-3 = X-2(3) >>X1X3 > X-2 > X-1 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. (C) 2013 Elsevier Ltd. All rights reserved.