Pulsed electric field inactivation of spoilage microorganisms in alcoholic beverages

In recent years, a number of new applications have emerged where pulsed power is being used in the treatment of waste and effluent, foodstuffs and beverages. One of these emerging applications is pulsed electric field (PEF) inactivation of microorganisms in liquid media. This involves the generation of electric fields of the order of 30 kV/cm across liquids contaminated with microorganisms. This induces a relatively large transmembrane potential that can lead to irreversible electroporation and consequently cell lysis. The nature of the PEF pulse profile is the subject of extensive study, and it has been reported that bipolar square waves provide superior inactivation when compared to monopolar pulses. A previous study, however, has challenged this view, and results will be presented demonstrating that more effective inactivation of bacteria can be achieved using the monopolar pulse. Results will also be given on the effect of monopolar pulse PEF applied to alcoholic beverages containing known spoilage microorganisms. This will highlight an apparent synergistic inactivation effect when microorganisms in alcoholic beverages are exposed to PEF.