In this paper, the inactivation kinetics of Bacillus subtilis spores by high-pressure thermal sterilization (HPTS) combining with lysozyme was studied, and the correlation between the inactivation amount of spores and the OD values of spore suspensions was investigated. The first-order kinetic model and Weibull model were used to describe the inactivation kinetics of the spores by HPTS combining with lysozyme, and the fitting effects of the kinetic models were compared and analyzed. The OD600 value was used to characterize the release of spore content. The OD260 and OD280 values were used to characterize the leakage of spore′s nucleic acids and proteins. At 600 MPa, 65 ℃ and 75 ℃, with 0.05%, 0.10%, and 0.30% lysozyme concentration, the inactivation of spores increased continuously with the increase of temperature and lysozyme concentration. The average coefficient of determination R2 was 0.972 for the Weibull model, the accuracy factor Af was 1.05-1.11, the bias factor Bf was 1.02-1.04, and the root mean square error RMSE was 0.14-0.48. The fitting effects of the Weibull model were better than the first-order kinetic model. With the increase of the treatment time, the OD600, OD260, OD280 values of the spore suspension also changed continuously, and their correlation coefficients with the changes of the spore′s inactivation amount were -0.972, 0.828, 0.848 respectively. The amount of spore inactivation was extremely significantly correlated with the OD600, OD260, and OD280 values of the spore suspension. However, the correlation between the OD600 value of the spore suspension and the amount of spore inactivation the most significant, and the OD600 value was easy to measure and could be used to predict the inactivation effect of spores quickly and reliably.
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