Validation of a mathematical model for predicting high pressure carbon dioxide inactivation kinetics of Escherichia coli spiked on fresh cut carrot

• Inactivation of Escherichia coli spiked on fresh cut carrot by high pressure carbon dioxide is assessed.
• The Weibull model fit with good agreement the inactivation kinetics.
• Validation of the Weibull model shows a good agreement between the experimental and the predicted inactivation data.

Inactivation kinetics of Escherichia coli spiked on fresh cut carrot and exposed to high pressure carbon dioxide (HPCD) treatment at several conditions of pressure (6, 8, 10, and 12 MPa) and two conditions of temperature (26 and 35 °C) were obtained as a function of the treatment time (up to 30 min).The Weibull model was applied to fit the inactivation kinetics and calculate δ and n model parameters for each pressure and temperature. The results demonstrated that the model was able to fit with good agreement the inactivation curves (high R2 and low RMSE values). In a second attempt, the model parameters were correlated with CO2 density resulting in a linear relationship. Validation of the proposed model was also performed at 6.6 and 10 MPa, 26 °C and at 8 MPa, 35 °C providing log reduction residual values (observed value–predicted value) lower than 0.50 and showing a good agreement between the experimental and the predicted inactivation data.The model proved to be a powerful tool to fit and predict, in the proposed operative range, the inactivation kinetics of E. coli spiked on fresh cut carrot treated by HPCD. The results demonstrated the potential of a relative simple correlative model for the interpretation of the inactivation data and for HPCD process design and optimization.

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