AVS 45th International Symposium
    Plasma Science and Technology Division Monday Sessions
       Session PS1-MoA

Paper PS1-MoA9
Use of a One Atmosphere Uniform Glow Discharge Plasma (OAUGDP) to Kill a Broad Spectrum of Microorganisms@footnote 1@

Monday, November 2, 1998, 4:40 pm, Room 314/315

Session: Environmental Issues and Emerging Technologies
Presenter: K. Kelly-Wintenberg, University of Tennessee
Authors: K. Kelly-Wintenberg, University of Tennessee
A. Hodge, University of Tennessee
T.C. Montie, University of Tennessee
L. Deleanu, University of Tennessee
J.R. Roth, University of Tennessee
D. Sherman, University of Tennessee
P. Tsai, Textile and Nonwovens Development Center (TANDEC)
L. Wadsworth, Textile and Nonwovens Development Center (TANDEC)
Correspondent: Click to Email
The medical, industrial, and food processing industries are constantly in search of new technologies to improve existing sterilization and pasteurization methodologies. Available techniques must deal with and overcome such problems as thermal sensisitivity and destruction by heat, formation of toxic byproducts, cost, and inefficiency in performance. We report the results of a newly invented plasma source, a One Atmosphere Uniform Glow Discharge Plasma (OAUGDP) that is capable of operating at atmospheric pressure in air and providing antimicrobial active species at room temperature. OAUGDP exposures have reduced log numbers of bacteria (E. coli, S. aureus, Deinococcus radiodurans, and Bacillus subtilis), bacterial endospores (Bacillus subtilis and Bacillus pumilus), and various yeast and bacterial viruses on a variety of surfaces. These surfaces included polypropylene, filter paper, paper strips, solid culture media, and glass. Experimental results showed at least a @>=@ 5 log@sub 10@ CFU reduction in bacteria within a range of 15-90 sec of exposure, whether the samples were exposed in conventional sterilization bags or directly exposed to the plasma. An exception to these very short exposure times were experiments with solid culture media where 5 min of plasma exposure was necessary to produce @>=@ 5 log@sub 10@ CFU reduction in bacterial counts. The effects of plasma treatment on bacterial cell structures were investigated by exposing cells to plasma for various durations and examining them by Transmission Electron Microscopy. These experiments showed cell lysis had occurred with the release of cellular contents. These data were consistent with spectrophotometer data in which the release of cellular constituents was measured as a change in absorption at 210nm and 260nm. With all microorganisms tested, a bi-phasic killing curve (logarithmic number of survivors versus time) was generated in plots of doseresponse data. Differences in susceptibilities of microorganisms observed on various surfaces suggested that the degree of lethality was dependent upon the time of diffusion of active species and the makeup of the microbial cellular surface. @FootnoteText@ @footnote 1@This work was supported in part by the Air Force under a STTR with Environmental Elements, Inc. of Baltimore, MD; and by the UTK Textiles and Nonwovens Development Center (TANDEC).