Killing of bacteria with electric pulses of high field strength

Bacteria of the type E. coli K12 have been treated in experiments using high-voltage pulses of short time (microseconds) as a killing agent. The role of different experimental parameters has been studied: kind of electrolyte, concentration, length of pulses, field strength, pH and temperature. Electrolytes with bivalent cations were found to reduce the lethal action. the relative rate of killed bacteria was shown to be mainly governed by the field strength and the treatment time, which is defined by the product of pulse number and decay time constant. From the obtained results a function has been developed which enables the precalculation of the killing rate for E. coli, provided that certain limits of experimental conditions are considered. No correlation between the applied electric energy and the lethal effect could be found.