An innovative sterilization system that uses an air plasma jet induced by an atmospheric pressure corona discharge
is developed. Because the sterilization is performed by the plasma reactions of air, the system does not
require any preparation of source gas cylinder. To obtain a fundamental understanding of the system, the gas
byproducts and the temperature of the plasma jet are investigated. The gas temperature is below the temperature
required to kill bacteria and yeast (Escherichia coli and Saccharomyces cerevisiae). Sterilizations by
applying the plasma jet for 0–5 s to several pieces of bacteria test paper on which either bacteria or yeast
exists are performed. After application of the nonthermal plasma jet, the bacteria or yeast are cultivated in
an incubator and then the numbers of colonies on the test piece are counted. From this test, it is found
that an exposure time of 1 s suffices to reduce both populations of bacteria and yeast by more than 88%.
Complete deactivations of both bacteria and yeast are performed by applying the plasma jet for 5 s.