Inactivation effect of pulsed electric field on Lactobacillu plantarum in apple juice and comparative analyses of three models

The inactivation effect of pulsed electric field(PEF) on Lactobacillu plantarum inoculated into apple juice and model analysis were investigated. The inactivation level on Lactobacillu plantarum increased with the increment of the electric field strength and the treatment time. About 4.135 log maximum reduction of Lactobacillu plantarum was achieved at 34 kV/cm for 1050 μs. The survival rate curves were fitted by the Hülsheger, Weibull and Log-logistic models, and the fitting effects of the three models were evaluated by using a series of indices including Accuracy Factor(Af), Bias Factor(Bf), the Sum of the Squares of the differences of the natural logarithm of the observed and predicted data(SS), the correlation coefficient(R²) and the Root Mean Square Error(RMSE) between the observed data and the predicted data. The comparison of these indices indicates that Log-logistic model can provide best fitness for the inactivation by PEF.