DESTRUCTION AND INHIBITION OF BACTERIAL-SPORES BY HIGH-VOLTAGE PULSEDELECTRIC-FIELD

Electric field strengths (E) from 20 to 50 kV/cm with pulse numbers ra nging from 15 to 50 were applied to Bacillus spore suspensions in 0.10 to 0.15% NaCl solution. The lowest count of viable spores, expressed as the logarithmic ratio of initial count before treatment to survivin g spores (log(No/N) greater than or equal to 3.425 and 5 at 25 degrees C) was obtained at 50 kV/cm with 30 and 50 pulses for B. subtilis and B. cereus, respectively. The log(No/N) increased with increased treat ment temperature or increased time gap between pulses. Spores were una ble to repair damage even after 1 mo.