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The inactivation and removal of airborne Bacillus atrophaeus endospores from air circulation systems using UVC and HEPA filters
Author(s) -
Luna V.A.,
Cans A.C.,
Amuso P.T.,
Cattani J.
Publication year - 2008
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2007.03569.x
Subject(s) - hepa , spore , bacillus megaterium , endospore , bacillus thuringiensis , bacillus cereus , microbiology and biotechnology , bacillus (shape) , air filter , bacillales , chemistry , chromatography , biology , filter (signal processing) , bacteria , mechanical engineering , genetics , inlet , bacillus subtilis , computer science , computer vision , engineering
Aims: To (i) evaluate the UV radiation in the ‘C’ band/high efficient particulate air (UVC/HEPA) instrument’s potential to inactivate spores of Bacillus atrophaeus and selected Bacillus species and (ii) test whether a titanium dioxide coating inside the cylindrical HEPA filter improves the system's efficacy. Methods and Results: Known amounts of dried spore preparations of B. atrophaeus, Bacillus cereus, Bacillus megaterium, Bacillus stearothermophilus and Bacillus thuringiensis were exposed to the UVC lamp within a cylindrical HEPA filter for different time lengths (30 min to 48 h) and with different air flow speeds (0–235 l s −1 ). The log 10 reduction (range 5–16 logs) of colony forming units for spores exposed to the UVC compared with the unexposed spores was significant ( P < 0·0001). The addition of a titanium dioxide (TiO 2 ) veneer to the interior surface of the HEPA filter significantly increased the inactivation of spores ( P < 0·0001). Conclusions: The UVC/HEPA unit could inactivate spores of B. atrophaeus, B. cereus, B. megaterium, B. stearothermophilus and B. thuringiensis. Significance and Impact of the Study: The UVC/HEPA unit represents an effective method of decontaminating circulating air within an air‐duct system as found in a building.