Abstract
Sterilization effect of Staphylococcus epidermidis on agar using dielectric barrier discharge (DBD) was evaluated. S. epidermidis was used as a specimen. The DBD reactor consisted of a glass plate and an aluminum foil. AC high-voltage with frequency of 1.2 kHz generated using a transformer driven by MOS-FETs and was applied to the aluminum foil. The reactor was put above the agar medium to generate the plasmas between the glass plate and the agar medium. To prevent current flow to the specimen, a metal mesh was set on the surface of the glass plate. The number of colony forming units (CFU) of S. epidermidis decreased with increasing input energy into the plasmas. The number of CFU decreased and ozone yield increased with increasing the number of wires of the metal mesh. On the other hands, energy efficiency for production of hydrogen peroxide in the purified water decreased with increasing the wire number of meshes. These results indicated that ozone produced by the discharges mainly contributed to the sterilization of S. epidermidis.
