AEM Accepts, published online ahead of print on 8 June 2007

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Youbi, G. K. Articles by Naïtali, M. Search for Related Content PubMed PubMed Citation Articles by Youbi, G. K. Articles by Naïtali, M. Agricola Articles by Youbi, G. K. Articles by Naïtali, M.

 Previous Article  |  Next Article 

Appl. Environ. Microbiol. doi:10.1128/AEM.00120-07
Copyright (c) 2007, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.

Evidence of the temporal post-discharge decontamination of bacteria by gliding electric discharges: application to Hafnia alvei

Georges Kamgang Youbi, Jean-Marie Herry, Marie-Noëlle Bellon-Fontaine, Jean-Louis Brisset, Avaly Doubla, and Murielle Naïtali^*

INRA, AgroParisTech, UMR 763 Bioadhésion et Hygiène des Matériaux, 25 avenue de la république, 91 300 Massy, France; Université de Rouen, Laboratoire d'Electrochimie et de Chimie Analytique, UFR de Sciences et Technologies, 76 821 Mont Saint-Aignan, France; Université de Yaoundé I, Laboratoire de Chimie minérale, Département de chimie inorganique, B.P 812 Yaoundé, Cameroon; AgroParisTech, INRA, UMR763 Bioadhésion et Hygiène des Matériaux, 1 avenue des olympiades, 91 300 Massy, France

^* To whom correspondence should be addressed. Email: murielle.naitali{at}agroparistech.fr.

This study aimed to characterize the bacteria-destroying properties of a gliding arc plasma device during electric discharges but also under temporal post-discharge conditions, i.e., when the discharge was switched off. This feature was reported for the first time in the literature in the case of the plasma destruction of micro-organisms. When cells of a model bacterium, Hafnia alvei, were exposed to electric discharges, followed or not by temporal post-discharges, survival curves presented a shoulder and then a 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 post discharge treatments was clearly affected by the discharge time t*: both the shoulder length Sl and the inactivation rate k_max were linearly modified as a function of t*. Nevertheless, all conditions tested (t* from 2 to 5 min) made it possible to achieve an abatement by at least 7 decimal logarithm units. Post-discharge treatment was also efficient versus bacteria not subjected to direct discharge and the disinfecting properties of plasma "activated water" were dependent on the treatment time t* of the solution. 2 min plasma treated water achieved a 3.7 decimal logarithm unit reduction in 20 min of application to cells, and an abatement superior to 7 decimal logarithm units resulted from the same contact time with 10 min plasma activated water. These disinfecting properties were maintained during storage of activated water for 30 min. After that, they declined as the storage time increased.