Comparative study on the use of different metal electrodes in low-pressure glow discharge plasma sterilization

The sterilizing efficacy of low-pressure direct current glow discharge hydrogen peroxide (H2O2) plasma generated by a planar parallel plate plasma source using the plasma enhanced chemical vapor deposition (PECVD) facility was tested. This study compares the effect of using different metals (copper, stainless steel, and aluminum) as electrodes in plasma sterilization of stainless steel dishes. Test samples were exposed to H2O2 plasma under different sets of discharge currents and exposure times. Bacillus subtilis was used as the test organism and microbial analysis was made by means of the standard plate count method of serial dilution and pour plating. Evaluation of microbial death was done using survival curves, percent reduction, and decimal reduction value. Results showed that sterilization using copper electrodes exhibited the highest decimal reduction value (D-value) and percent reduction among the three electrodes. However, statistical analysis using multivariate analysis of variance (MANOVA) at 0.05 significance level assessed that the type of electrode material is not a significant factor in the H2O2 plasma sterilization of Bacillus subtilis cells. © 2014 by Begell House, Inc.