Decontamination of Bacillus thuringiensis spores on selected surfaces by chlorine dioxide gas.
* The use of gaseous Cl[Osub.2], however, has been primarily limited to pulp bleaching in the paper industry.
* Studies on the use of gaseous Cl[O.sub.2] for disinfection of surfaces are not as extensive as those on the use of aqueous Cl[O.sub.2].
* This study examined the efficacy of chlorine dioxide Cl[O.sub.2]) gas for the decontamination of Bacillus thuringiensis spores on paper, wood, epoxy, and plastic surfaces.
* Bacillus thuringiensis was used as a surrogate for B. anthracis.
* The highest population of surviving spores was found on the paper surface.
* The lowest was on the plastic surface.
* No significant difference was seen between the surviving spore populations on the wood and epoxy surfaces.
* The minimum Cl[O.sub.2] gas concentration needed to completely inactivate an inoculation of 6 log spores was
--30 mg/L for paper and wood surfaces,
--25 mg/L for epoxy surfaces, and
--20 mg/L for plastic surfaces.
* Words printed in black ink on the paper surface were not bleached or discolored.
* Thus, Cl[O.sub.2] gas at 30 mg/L concentration is feasible for decontamination of letters or paper documents without damage to the contents.
* The wood surface was not discolored after Cl[O.sub.2] gas treatments.
* Cl[O.sub.2] gas treatment might therefore be suitable for the decontamination of an environment containing furniture or other wooden structures, like doors and windows.
* Because of differences in surface structures, however, decontamination of a room containing various materials, such as rugs, cloths, and computers, presents challenges.
* When strips are used to verify the effectiveness of Cl[O.sub.2] gas treatments, a battery of different material surfaces should be used for the strips.
* It was also found that the Cl[O.sub.2] gas concentrations decreased rapidly over time.
* In the first six hours, the concentrations were reduced by more than 80 percent.
* This reduction might be due to rapid decomposition, to absorption by or reaction with experimental materials, or both.
* It may be necessary, in the decontamination of a large environment, to add Cl[O.sub.2] gas after a short exposure time, such as 0.5 to 6 hours.
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|Title Annotation:||Practical Stuff!|
|Publication:||Journal of Environmental Health|
|Date:||Nov 1, 2003|
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