Fast flow-through non-thermal pasteurization using constant radiofrequency electric fields

• Novel method for non-thermal treatment of fluids.
• Liquid flows at high speed through a chamber where an AC field is constantly applied.
• No need for pulsating high-voltage generators.
• Simulation: no significant heating occurs using feasible dimensions and velocities.
• In vitro study: Escherichia coli inactivation in water is demonstrated.

Pulsed electric field technologies have captured the attention of researchers on food pasteurization because of their non-thermal inactivation mechanism, which results in fresh-like products. Nevertheless, high voltage pulsing required by these technologies implies complex and costly generators. Here, as an alternative, it is proposed a method, partially inherited from research on cell electroporation for gene transfection, in which the liquid to be treated flows at high speed through a miniature chamber where the electric field is permanently applied. In particular, it is proposed that the constantly applied electric field consists of an AC signal (> 100 kHz) so that electrochemical by-products are minimized. The method, while being compatible with batch processing, will allow use of lower voltages and will avoid the pulsation requirement. The proposal is accompanied by a numerical study and an in vitro study which demonstrate its feasibility.Industrial relevanceThis paper describes an electroporation based method for non-thermal pasteurization of liquids that, in comparison to existing pulsed electric field technologies, does not require high voltage pulsed generators. The method consists in circulating the liquid at high speed through a miniature chamber where an AC electric field of moderate magnitude is permanently applied. By combining several miniature chambers in parallel and in series batch processing will be possible. Here it is analyzed and demonstrated the performance of a single miniature chamber.