Experimental Research on Inactivation of Bacteria by Using Dielectric Barrier Discharge

S. aureus and E. coli were treated by using dielectric barrier discharge (DBD). It was found that a logarithm reduction factor of 5 for both S. aureus and E. coli could be obtained in less than 120 s of treatment. The results of scanning electron microscopy showed that the low-temperature plasma that was induced by DBD destroyed the outer membrane of the bacteria. It was shown that E. coli was more susceptible to the inactivation effect by the DBD than S. aureus because E. coli has a thinner cell surface structure. This paper compares the bacteria inactivation effect of DBD with that of ozone generator and ultraviolet lamp, and results show that the charged particles and active free radicals penetrating through the outer membrane of the bacteria might play a major role during the treatment process.