Bleach treatment neutralizes mold allergens
Treatment with household bleach reduces the allergy-inducing ability of mold spores, a new study shows.
Current efforts to remediate mold-contaminated buildings require replacement of contaminated materials, Dr. John W. Martyny of the National Jewish Medical and Research Center in Denver and colleagues note in the Journal of Allergy and Clinical immunology.
Also, the Environmental Protection Agency and many investigators argue that killing mold is not enough to reduce its allergenicity. Dilute sodium hypochlorite is known to kill mold, but it is not clear if it reduces mold’s ability to produce allergic reactions.
Martyny and his team conducted the current study, funded by the Clorox Co., to determine if diluted bleach would destroy the ability of mold to produce an allergic response as well as kill the organism. Several studies, they point out, have found bleach can neutralize other types of household allergens, such as dust mite and cockroach proteins.
The researchers grew Aspergillus fumigatus on samples of three types of construction materials, as well as in solution. The samples and cultures were then treated with dilute bleach; Tilex, a cleaning product containing detergent and bleach; or water only.
The researchers then evaluated the number of spores using scanning electron microscopy and tested for viable mold. They also checked treated samples for antigens using ELISA and skin prick testing.
While bleach or Tilex treatment did not reduce the number of spores, surface allergens were no longer detectable in the treated samples. The surface of the spores treated with bleach or Tilex also showed changes in appearance. After adding bleach to the mold in aqueous solution, A. fumigatus allergens were no longer detectable by ELISA.
Skin prick tests found bleach treatment eliminated a response in five of eight mold-allergic individuals, while Tilex treatment inhibited response in seven of eight.
Some authorities on mold contamination, as well as some government agencies, recommend against treating fungi contaminated surfaces with bleach solutions, given the concern that substantial amounts of organic material may neutralize their disinfectant capacities, Martyny and colleagues note.
“On the basis of the results of our study, sodium hypochlorite-containing products should be reconsidered as one of the tools in the remediation of mold-contaminated buildings,” the researchers conclude.
SOURCE: Journal of Allergy and Clinical Immunology, September 2005.
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