Modeling the thermoultrasound inactivation of Vibrio parahaemolyticus in raw peeled shrimps.

Vibrio parahaemolyticus has been identified as a causative agent for seafoodborne diseases worldwide. The effect of thermoultrasound treatment on the survival of V. parahaemolyticus in raw peeled shrimps was investigated in this study as an alternative bacterial inactivation method in seafood as part of the postharvest washing process. Raw peeled shrimps inoculated with V. parahaemolyticus were treated with mild heat (47, 50, and 53°C) combined with ultrasound (0, 96, 150, and 204 W) based on a 3 × 4 full factorial design, and the bacterial survival curves were fitted with a Weibull model. Because of the high correlations of the shape parameter n and the scale parameter β in the Weibull model, an overall n was estimated from the whole set of bacterial inactivation data and β values were estimated for each set of inactivation curves accordingly. A response surface model was generated to describe the scale parameter as a function of temperature and ultrasonic power. The results indicated that the Weibull model with the overall n value could be used to describe the bacterial reduction with the time of exposure to the thermoultrasound treatments, which was well supported by the small root mean square errors (RMSE) and the high coefficients of determination (R(2)). The quadratic model was validated with independent experiments within the prediction range. Statistical indices (R(2) = 0.99; P < 0.0001; RMSE = 0.17) and validation parameters (bias factor = 0.97; accuracy factor = 1.03) indicated satisfactory performance of the quadratic model. The results indicated that the thermoultrasound treatment is effective, simple, and cost-effective for inactivation of V. parahaemolyticus in shrimps during the postharvest washing process.