Inactivation kinetics of Clostridium sporogenes spores by pulsed electric field (PEF)

The kinetics of inactivation of Clostridium sporogenes spores as a surrogate for the sterilization marker Clostridium botulinum using Pulsed Electric Field (PEF) treatment has not been previously investigated. Hence, this study aimed to evaluate and determine the kinetics of C. sporogenes spore inactivation by PEF. The spore suspensions of C. sporogenes were treated using PEF at an electric field intensity of 36 kV/cm with a residence time of 1.302 s. The spore inactivation kinetics were analyzed using several mathematical models, including log-linear, log-linear shoulder, and Weibull models. The electroporation effects were evaluated by measuring the concentration of Ca 2+ released into the suspension following PEF treatment. PEF treatment resulted in a reduction of C. sporogenes spores by up to 3.6 log cycles. The inactivation curve of C. sporogenes spores demonstrated a concave downward shape, with a shoulder pattern at the initial time and an exponential decrease as the process time increased. The spore electroporation was evidenced by an increase in Ca 2+ concentration in the suspension from 1.58 to 2.03 ppm after PEF treatment. The death rate of C. sporogenes spores ( kmax ) increased and the shoulder length ( S i ) decreased with higher electric field strengths. A concave downward curve of the inactivation curve is shown by a curve shape value ( p )> 1. The log-linear shoulder was the best model to describe C. sporogenes spore inactivation. The D PEF and Z PEF values of C. sporogenes spores in the log-linear, log-linear shoulder and Weibull models were in the ranges 2.46–4.222 s and 25–32 kV/cm. These findings demonstrate that PEF can effectively inactivate C. sporogenes spores and that kinetic modeling provides valuable parameters for predicting spore inactivation during PEF processing.