Evidence of Temporal Postdischarge Decontamination of Bacteria by Gliding Electric Discharges: Application to Hafnia alvei

Abstract

This study aimed to characterize the bacterium-destroying properties of a gliding arc plasma device during electric discharges and also under temporal postdischarge conditions (i.e., when the discharge was switched off). This phenomenon was reported for the first time in the literature in the case of the plasma destruction of microorganisms. When cells of a model bacterium, Hafnia alvei, were exposed to electric discharges, followed or not followed by temporal postdischarges, the survival curves exhibited a shoulder and then log-linear decay. These destruction kinetics were modeled using GinaFiT, a freeware tool to assess microbial survival curves, and adjustment parameters were determined. The efficiency of postdischarge treatments was clearly affected by the discharge time (t*); both the shoulder length and the inactivation rate k max were linearly modified as a function of t*. Nevertheless, all conditions tested (t* ranging from 2 to 5 min) made it possible to achieve an abatement of at least 7 decimal logarithm units. Postdischarge treatment was also efficient against bacteria not subjected to direct discharge, and the disinfecting properties of "plasma-activated water" were dependent on the treatment time for the solution. Water treated with plasma for 2 min achieved a 3.7-decimal-logarithm-unit reduction in 20 min after application to cells, and abatement greater than 7 decimal logarithm units resulted from the same contact time with water activated with plasma for 10 min. These disinfecting properties were maintained during storage of activated water for 30 min. After that, they declined as the storage time increased.

Atmospheric pressure plasma treatment of Listeria innocua and Escherichia coli at polysaccharide surfaces: Inactivation kinetics and flow cytometric characterization

“…They proposed the application of the Weibull model to the description of non-thermal plasma inactivation, whereas an empirical model seemed to better describe the obtained triphasic inactivation curves. The GInaFiTtool was successfully applied to microbial inactivation of bacteria and yeast by gliding arc discharges (Kamgang, 2007;Kamgang-Youbi et al, 2007.…”

Combined Effects of Long-Living Chemical Species during Microbial Inactivation Using Atmospheric Plasma-Treated Water

“…Atmospheric nonthermal plasmas of the gliding-arc type (Glidarc) (9, 25) were found to be efficient against microorganisms for treatments performed under burning discharge (12,13,22,26), and the inactivation of cells in water could continue after the discharge had been switched off (13). Microbial cells were also killed by contact with water that had first been activated by discharges (and so-called plasma-activated water [PAW]) without being themselves subjected to the plasma plume (14, 15).…”

Plasma Technology: A New Remediation for Water Purification with or without Nanoparticles

“…Comparisons with the pulsed-electric fi eld (PEF) method indicated that the decontamination effi ciency of the PWC method has been found to be slightly higher than that of the PEF method [26]. Atmospheric non-thermal plasma of the gliding-arc type (Glidarc) [27,28] has been found to be effi cient against microorganisms for treatments performed under burning discharge [29,30], and the inactivation of cells in water continued aft er the discharge had been switched off [29]. Microbial cells have been found to be killed by contact with water that had fi rst been activated by electric discharges (and so-called plasma-activated water [PAW]) without themselves being subjected to the plasma plume [31].…”