Bactericidal effects of negative and positive ions generated in nitrogen on Escherichia coli

Abstract The bactericidal effect of both negative and positive ions generated by a dc electrical corona in nitrogen were investigated. Tryptic soy broth agar plates inoculated with Escherichia coli ( E. coli ) (strain DH5- α ) were placed into a custom-built multi-point-to-plane ion generator situated within a glass chamber. Under a nitrogen atmosphere the plates were exposed to either negative or positive ions for various time periods. The plates were then removed and incubated at 37°C for 15 h and the colonies counted. Exposure to either negative or positive ions produced significant reductions ( p E. coli cells. Cell death could be due to a physiological change in the outer membrane as a result of ionic interactions.