Contact: Jim Sliwa
jsliwa@asmusa.org
202-942-9297
American Society for Microbiology
Vinegar increases killing power of bleach
Adding white vinegar to diluted household bleach greatly increases the disinfecting power of the solution, making it strong enough to kill even bacterial spores. Researchers from MicroChem Lab, Inc. in Euless, Texas, report their findings today at the 2006 ASM Biodefense Research Meeting.
Sodium hypochlorite (NaOCl) in the form of laundry bleach is available in most households. The concentrate is about 5.25 to 6 percent NaOCl, and the pH value is about 12. Sodium hypochlorite is stable for many months at this high alkaline pH value.
“Laundry bleach is commonly diluted about 10 to 25-fold with tap water to about 2000 to 5000 parts per million of free available chlorine for use as an environmental surface disinfectant, without regard to the pH value of the diluted bleach. However, the pH value is very important for the antimicrobial effectiveness of bleach,” says Norman Miner, a researcher on the study.
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Miner recommends first diluting one cup of household bleach in one gallon of water and then adding one cup of white vinegar.