Abstract: Previous studies on the effect of microsecond pulsed electric fields on bacteria have shown that the lethality increases linearly with pulse duration and exponentially with electric field strength. In order to determine the validity of this law for submicrosecond pulses, we applied pulses of fifty nanosecond duration to two strains of E. coli and to a marine crustacean. The results indicated that even at this short pulse duration, the empirical law not only holds for bacteria, but also for more complicated organisms. Theoretical considerations, however, and the observation of a pronounced difference in the field induced lethality of two strains of E. coli led us to believe that a change in the effect can be expected when the pulse duration is reduced further. The observed dependance of micro-organism lethality or temporary damage on field strength and pulse duration allows us to improve the energy efficiency of systems which make use of the effect. Examples are sterilizers (e.g., for food and water) and electrical filters for the prevention of biofouling in cooling systems.!11
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