The Microbial Inactivation by High Voltage Pulsed Electric Field

High Voltage (HV) Pulsed Electric Field (PEF) has been extensively used for the treatment dairy products and juices to inactivate microbes. The present work suggests HV PEF to disinfect the effect of microbes commonly found in water and milk. The PEF of the order of 1.2 microsecond rise time to 50 microsecond tail time in parallel plate static chamber has been applied to get microbes’ free water and milk. For microbial inactivation by PEF the field intensity was varied from zero to 180kV/cm and number of pulses has been varied from zero to 100. In first case field intensity was kept constant and numbers of pulses were varied while in another case numbers of pulses are kept constant and field intensity was varied. In both the cases survival ratio of microbes has been calculated. This experiment's objective was to find out the survival ratio of five kinds of bacteria namely Enterobaracter Aerogenes, Escherichia coli, Listeria Monocytogene, Staphylococcus Aurous, and Acetobacter commonly found in water and milk. The survival ratio of some of microbes were observed very low 0.000001, at 40kV and 40 pulses and some other microbes has also very low survival ratio at more 40kV and number of pulses more than 40. E. coli was completely inactivated at 80kV whereas L.monocytogenes reduced by only two orders of magnitudes at 140kV.It has been found that the bacteria were destroyed due to field-induced at the protecting wall of microbes and not due to ohmic heating.