Inactivation of Staphylococcus Aureus Using Pulsed Electric Field Treatment Under Treatment Time Variation

Abstract

Pulsed electric field treatment has been successfully applied in various liquid foods in order to inactivate microorganisms through the process of electroporation. The shelf life of liquid foods can be extended using pulsed electric field treatment thereby maintaining the quality attributes of foods with less energy consumption when compared with other heat treatment methods. However, few efforts have been made by using Pulsed electric field technology on electric field application through specific electrode materials focusing on specific type of microorganisms. In this research, Pulsed Electric Field treatment chamber has been modelled using electromagnetic simulation software and has been implemented practically for experimental testing. Titanium electrodes have been used for successful pulsed power applications on culture medium, where Staphylococcus aureus ATCC 25923 was inoculated at 107 colony forming units per ml in sterile water. The impact of Pulsed Electric Field application on microbial colonies has been observed for treatment time variation from one to six minutes. The pulse width has been set to 1 microsecond at a pulse repetition rate of 50 pulses per second. The results have demonstrated that: (i) up to 85% of field reduction could be observed on simulated electrode edges; (ii) under experimentation, the best inactivation efficiency has been obtained at one minute (Continuous) and six minutes (Discrete), with field requirements of 35 kV/cm and 39 kV/cm, resulting in 1.89 and 1.82 of bacterial log reduction respectively.