EFFECT OF SHORT HV PULSES ON BACTERIA AND FUNGI

The survival of three kinds of microorganisms under strong-pulse elect ric field conditions was investigated with a possible application of t he electric pulse method for sterilization of consumable liquids. The results of the investigations of survival ratio of Gram-negative (Esch erichia coli, Yersinia enterocolitica) and Gram-positive (Staphylococc us aureus, Listeria monocytogenes) bacteria and yeastlike fungi (Candi da albicans) are presented. The HV pulses with peak voltage U = 0 to 1 00 kV and rise time t(n) = 0.5 to 1.2 mu s were applied. The microorga nisms were suspended in an NaCl solution with gamma = 6 to 13 mS/cm co nductivity and pH = 7.2. The experimental setup and the dependency of the microorganism survival ratio on the rise time, peak voltage and on the number of pulses applied, are presented. It has been found that t he lethal effect on microorganisms caused by HV pulses depends on the pulse parameters as well as on the kind of microorganism being treated .