P1-144 Predictive Modeling for the Thermo-ultrasound Inactivation of Vibrio parahaemolyticus in Shrimp during Post-harvest Washing Process

Monday, July 29, 2013
Exhibit Hall (Charlotte Convention Center)
Wen Wang, Zhejiang University, Hangzhou, China
Min Li, Iowa State University, Ames, IA
Yanbin Li, University of Arkansas, Fayetteville, AR
Introduction: Vibrio parahaemolyticus has been identified as an important causative agent of human gastroenteritis in seafood such as shrimp. Ultrasound and mild heat treatment are effective intervention strategies to decontaminate V. parahaemolyticus in shrimps. However, there is limited information on their combined application to control V. parahaemolyticus in shrimps.

Purpose:  The study aimed to develop a predictive model to evaluate the combined effect of ultrasound and mild heat on reducing V. parahaeomolyticusin shrimps during the postharvest washing process. 

Methods:  Raw shrimps inoculated with V. parahaeomolyticus were treated with ultrasound (96, 150, and 205 W) combined with mild heat (47, 50, and 53ºC) based on a 3 × 3 full factorial design and the bacterial survival curves were fitted with a Weibull model. The time for a 4-log CFU/g of bacterial reduction (t4d) was calculated based on parameter estimates of the Weibull model to evaluate the inactivation rates and a response surface model was developed to describe the changes of t4d as a function of temperature and ultrasonic power. The model was validated with independent experiments within the model range.

Results: The results indicated that the models were significant (P < 0.05) with high adjusted coefficients of determination (R2-adj = 0.89-0.98). The response surface model showed that t4d was reduced when temperature and ultrasonic power increased and there was a significant positive interaction effect (P < 0.01) between the two factors, indicating thermo-ultrasound treatments accelerated the inactivation of V. parahaemolyticus. Bias factor (Bf = 1.02) and accuracy factor (Af = 1.09) calculated based on the validation data indicated a satisfied performance of the model.

Significance: The developed predictive model could be used to design appropriate regimens of ultrasound and mild heat treatment to achieve desirable V. parahaeomolyticus reduction in shrimps.