Abstract:

Low temperature plasma glow discharge sterilizer was developed and used to study the bactericidal kinetics of six
microorganisms including Escherichia coli, Shigella sonnei, Staphylococcus aureus, Listeria monocytogenes, Aspergillus
flavus and Candida albicans. Moreover, the bactericidal mechanisms were studied by scanning electron microscopy,
transmission electron microscopy, DNA electrophoresis and spectroscopy analysis. It was shown that low temperature glow
discharge plasma could kill E. coli, S. sonnei, S. aureus, L. monocytogenes, A. flavus and C. albicansi effectively in 2, 1.5, 3,
4, 10 and 10 minutes, respectively. According to the bactericidal kinetic curves, the six microorganisms were classified into
three categories, namely gram-negative bacteria, gram-positive bacteria and fungi, which may be resulted from the different
structures of cell walls of microorganisms. Furthermore, the charged particles with high energy produced by low temperature
glow discharge plasma played a dominant role in plasma-induced bacterial spore inactivation by destroying bacterial cell
walls. This study may provide an important method basis for the application of low temperature glow discharge plasma in
sterilization of microorganisms.

Key words: low temperature plasma, glow discharge, sterilization, kinetics, mechanism