Inactivating microorganisms using a pulsed electric field continuous treatment system

TLDR

High‑voltage pulsed electric fields can inactivate microorganisms in liquids and offer a promising nonthermal pasteurization method that could transform food preservation by delivering microbiologically safe, minimally processed, fresh‑like products. The authors built a laboratory‑scale continuous‑flow system comprising a high‑voltage pulse generator, a coaxial liquid chamber, fiber‑optic temperature sensing, and data acquisition, and applied exponentially decaying pulses to liquids containing *Escherichia coli*, *Staphylococcus aureus*, and *Saccharomyces cerevisiae*. The system achieved over six‑order‑of‑magnitude reductions in microbial viability while keeping the food temperature below 40 °C.

Abstract

High-voltage pulsed electric fields (PEFs) can be used to inactivate microorganisms in liquids. Applying PEF technology to food pasteurization is a promising nonthermal method, which may radically change food preservation processes and provide consumers with microbiologically safe, minimally processed, fresh-like products. A continuous-flow system in a laboratory-size prototype was constructed for the nonthermal pasteurization of liquid foods with PEF technology. Major components in the prototype include a high-voltage repetitive pulse generator, a coaxial liquid food treatment chamber, a fiber-optic temperature sensing instrument and a data acquisition system. Microbial inactivation tests were conducted in the continuous PEF treatment system. Repetitive high-voltage pulses with an exponential decaying waveshape were applied to the liquid food which was pumped through the treatment chamber. Test microorganisms selected for inactivation were Escherichia coli, Staphylococcus aureus and Saccharomyces cerevisiae. Over 6-order-of-magnitude reductions in the viability of selected microorganisms were achieved while the food temperature was maintained below 40/spl deg/C.