2019 年 20 巻 2 号 p. 63-70
Pulsed Electric Field (PEF) treatment is considered as nonthermal due to application of ultra short high voltage pulses in liquid foods to extend their shelf life. In today’s world, water decontamination becomes extremely necessary to safeguard people from health ailments. The objective of this work focusses on inactivation of naturally prevailing Escherichia coli and Fecal coliform bacteria in environmental water using titanium electrodes. In this study, the PEF treatment chamber was designed to be used for both static and continuous modes of treatment. Bipolar square wave pulses having 1μs pulse width at a rise time of 160 ns and pulse repetition frequency between 48 to 50 Hz were used in this research. From the results, it was observed that titanium effectively inactivated both the microorganisms at a minimum treatment time of 60 seconds at 33.9°C while conventional stainless steel required 120 seconds at a temperature of 40.1°C under the same experimental conditions. Also, the relationship between treatment time and temperature remained linear despite the change in electric field. Results confirmed that (i) Titanium is more suitable in PEF for water decontamination due to its high reactivity than stainless steel (ii) Using titanium, complete ABSENCE of the two microorganisms could be possible in water at a nominal field strength of 24 kV/cm with much less temperature requirement.
