Pasteurization of Escherichia Coli in ICE using Voltage Application

This paper reports the pasteurization of Escherichia coli in frozen NaCl solutions by applying freezing and voltage. The experimental samples consisted of frozen NaCl solutions containing E. coli. We applied DC or AC voltage to the frozen samples stored in freezers at -20°C or -60°C. The results were as follows: In the -20°C freezer, the bactericidal effect on E. coli in frozen 0.01 and 0.53 mol/L NaCl solutions with DC voltage application was higher than with freezing alone (no voltage application). Conversely, AC voltage application to the frozen NaCl solutions showed no bactericidal effect. At -60°C, applying DC 500 V to the frozen NaCl solutions showed no bactericidal effect. Additionally, glycerin in the frozen NaCl solutions inhibited the pasteurization effect of freezing and voltage application. However, adding ethanol to the frozen 0.53 mol/L NaCl solutions enhanced the bactericidal effect of freezing and voltage application.