The sterilization of E. coli (ATCC8099) using an atmospheric pressure, air DBD plasma driven by 100 Hz
high-voltage power supply was investigated in this paper. The results showed that germicidal efficiency
was closely related to the plasma treatment time, the gap spacing, the initial cell density and the surface
characters of substrate materials. The germicidal efficiency was 99.999% under the conditions of 5-min
plasma treatment, 3-cm gap spacing and on PET films. After plasma exposure for 5 min, the temperature
was observed below 43 ◦C which could not lead to inactivate E. coli. The observation of protein leakage
and cell morphology alteration by transmission electron microscopy (TEM) techniques revealed that the
etching action on cell membrane by electrons, ions and radicals was primary reason of DBD air plasma
sterilization.