Photoinactivation of the Escherichia coli by the Pulsed Dielectric Barrier Discharge Excilamp Krypton Chlorine Emitted at 222 nm

The photoinactivation of the Escherichia coli bacteria with the pulsed dielectric barrier discharge excilamp krypton chorine (KrCl) emitted at 222 nm is presented. The Escherichia coli, with the initial density of 34.10⁶ colony forming units (CFU)/??L, has been irradiated in the aqueous and on the surface medias, respectively. A high reduction rate in the survival density of E. coli has been reached by the photoinactivation in both media during the first 30 s. The photoinactivation resulted in the logarithmic reduction factor of 5.6 log and 5.1 log within irradiation time of 30 s on the surface and in the aqueous medias, respectively. At the high dose of 2880 mJ/cm² , the logarithmic reduction factor reached 6.1 log and 5.5 log on the surface and in the aqueous medias, respectively. The first tailing plateau was appeared on the surface and in the aqueous medias at 60 and 300 s of irradiation time, respectively.