Effect of Amino Acid in Aqueous Solution on Sterilization of Escherichia coli by High Electric Field Pulse

Abstract

We have been investigating the sterilization of liquid food by high electric field pulse. The sample was Escherichia coli (JM103) in aqueous solution of L-Serine, L-Alanine, L-Histidine, L-Glutamic acid, D-Glutamic acid, L-Aspartic acid, K₂HPO₄, or KH₂PO₄. High voltage pulse (-4.40 kV) was applied to the each sample at room temperature. As results, the survival rates of L-Glutamic acid, D-Glutamic acid, L-Aspartic acid, K₂HPO₄, or KH₂PO₄ samples greatly decrease with the number of applied pulses. On the other hand, the survival rates of L-Serine, L-Alanine, or L-Histidine samples slightly decrease. The experimental results suggest that the survival rate of E. coli by high electric field pulse sterilization is governed the anions or negative charges in aqueous solution.