ROOM-TEMPERATURE STERILIZATION OF SURFACES AND FABRICS WITH A ONE ATMOSPHERE UNIFORM GLOW-DISCHARGE PLASMA

We report the results of an interdisciplinary collaboration formed to assess the sterilizing capabilities of the One Atmosphere Uniform Glow Discharge Plasma (OAUGDP), This newly-invented source of glow dischar ge plasma (the fourth state of matter) is capable of operating at atmo spheric pressure in air and other gases, and of providing antimicrobia l active species to surfaces and workpieces at room temperature as jud ged by viable plate counts. OAUGDP exposures have reduced log numbers of bacteria, Staphylococcus aureus and Escherichia coli, and endospore s from Bacillus stearothermophilus and Bacillus subtilis on seeded sol id surfaces, fabrics, filter paper, and powdered culture media at room temperature, Initial experimental data showed a two-log(10),, CFU red uction of bacteria when 2 x 10(2) cells were seeded on filter paper. R esults showed greater than or equal to 3 log(10) CFU reduction when po lypropylene samples seeded with E. coli (5 x 10(4)) were exposed, whil e a 30 s exposure time was required for similar killing with S.aureus- seeded polypropylene samples. The exposure times required to effect gr eater than or equal to 6 log(10) CFU reduction of E. coli and S. aureu s on polypropylene samples were no longer than 30 s, Experiments with seeded samples in sealed commercial sterilization bags showed little o r no differences in exposure times compared to unwrapped samples, Plas ma exposure times of less than 5 min generated greater than or equal t o 5 log(10) CFU reduction of commercially prepared Bacillus subtilis s pores (1 x 10(6)); 7 min OAUGDP exposures were required to generate a greater than or equal to 3 log(10) CFU reduction for Bacillus stearoth ermophilus spores. For all microorganisms tested, a biphasic curve was generated when the number of survivors vs time was plotted in dose-re sponse cures. Several proposed mechanisms of killing at room temperatu re by the OAUGDP are discussed.