Structure optimization of pulsed electric field processor and its sterilization effect

Abstract

Pulsed electric field (PEF) technology is a highly promising non-thermal processing technique, which holds great potential for sterilizing liquid food. The effectiveness of this treatment depends on two crucial factors: pulse parameters and the structure of the processor. In this study, we focus on optimizing the shape of insulators within the PEF processor to improve the sterilization effect. This research provides a reliable technical reference for designing industrial equipment. The numerical simulation of multi-physics fields was employed to analyze the temperature, electric field, and fluid field distributions for different insulators. Ultimately, the geometric structure of the insulator was optimized by embedding a 0.7-mm arc. Sterilization experiments were then conducted on Escherichia coli and Staphylococcus aureus suspensions with conductivities similar to those of real grapefruit juice. The sterilization effect of the processor with the optimized structure and the maximum applied voltage was examined at the same driving frequency. The results indicate that compared to the original structure, there is an increase in withstanding voltage by 5-10 kV while maintaining significantly improved bactericidal effects at the same applied voltage. Furthermore, we preliminarily discussed the sterilization mechanism by combining electroporation theory with the electroporation threshold of S. aureus.