Sterilization of escherichia coli by Marx circuit with switches using bipolar junction transistors

High electric field pulse sterilization is one of nonheat sterilization, and is a new sterilization technique for liquid food. In this sterilization method, we apply high voltage pulses to liquid food. The general impulse generator is the Marx circuit. The impulse generator with the spark gap switch has two disadvantages; the charge time is long and the rise rate of applied voltage is slow. In this study, we report the sterilization of Escherichia coll by Marx Circuit with Switches Using Bipolar Junction Transistors (BJT). The experimental sample is 1.0 ×10−3 mol/L NaCl aqueous solution containing E. coli. We applied pulse voltage to the sample by the 10 stages Marx circuit with switches using BJT 2SC2824. The pulse interval is 1 seconds. The survival number of E. coli was counted by the colony counting method. As the results, the survival number of E. coli was decreased with the increase of the number of pulses. We estimated the survival number of E. coli by sterilization mechanism for high electric field pulse. The experimental results of survival number disagreed with the calculated values.