Nonthermal Biological Treatments Using Discharge Plasma Produced by Pulsed Power 3. Bacteria Decontamination by Pulsed Power

Abstract

In order to explore the effect of Pulsed Electric Fields (PEF) with pulses on the order of the charging time of bacterial membranes, we studied the effect of 45 ns pulses on the viability of bacillus subtilis in its vegetative state. A 30 Ω Blumlein generator with a low inductance spark gap switch delivers square wave voltage pulses of 45 ns duration to the electrodes in the bacterial treatment chamber. The rise time, which was varied from 2 ns (f< 200 MHz) to 20 ns (f< 50 MHz), determines the high frequency components in the Fourier spectrum of the pulse. Among pulses of different rise times, having the same total energy, those with the shortest rise time were found to kill bacteria more effectively. These results indicate that the high frequency components in the PEF deposit the electrical energy in the cell and affect intracellular structures.