We all want to live in a clean indoor environment, but of course there are degrees of “clean” and different requirements for “clean,” depending on the living space targeted. The “clean your room” chore given to children generally refers to straightening up and organizing stray objects into drawers, closets and onto shelves. It might involve dusting and vacuuming, but it is decidedly different from cleaning a bathroom or kitchen where germs present a more obvious risk
Cleaning, accomplished with soap–or detergent–and water, refers to the physical removal of dirt and grime, and in the process, some portion of the germs on a given surface. Sometimes cleaning tools, including sponges and cloths, simply move germs from one surface to another. Disinfecting, on the other hand, refers to killing a high percentage of the germs on a surface or rendering them incapable of reproducing. Sanitizing is another relevant term in this discussion. According to www.flu.gov, sanitizing lowers the number of germs on surfaces to a safe level, as judged by public health standards or requirements. The process works by either cleaning or disinfection to reduce the risk of spreading infection. Finally, sterilizing destroys all forms of microbial life and is used mainly in healthcare and laboratory settings.
The Order of Operations
If disinfecting a surface is the task at hand—for example, you might be tackling a food preparation counter that has just contacted raw meat or fish—the order of operations is important. Just remember “C” (cleaning) comes before “D” (disinfection). First, clean the surface with detergent or general household cleaner to remove any visible food or waste particles. Second, rinse the surface with water, dry and then apply disinfectant.
A quick home-made disinfectant can be prepared by adding one-half tablespoon of ordinary household bleach to one-half gallon of plain water. Apply the solution to the (cleaned, dry) surface and let air dry. That’s it! No rinsing is required at that bleach solution concentration.
Why Chlorine Bleach?
Chlorine bleach is an inexpensive, effective surface disinfectant at very low dilutions. A 2011 Water Quality & Health Council survey of 1,000 American adults found that nearly half of all respondents (47 percent) overestimated the amount of bleach needed in a gallon of water to kill common foodborne germs. In a 2009 study by Yang et al.1, five common household products were tested for their ability to destroy three of the most common kitchen germs (E. coli O157:H7, Salmonella and Listeria). Of chlorine bleach, hydrogen peroxide, white vinegar, lemon/lime juice and baking soda, only chlorine bleach solution successfully destroyed all three of these types of foodborne bacteria. Chlorine bleach is also effective against viruses, and it is widely recommended for disinfecting surfaces against the extremely contagious norovirus (norovirus posters).
Always keep chlorine bleach out of the reach of children. Make chlorine bleach solutions fresh daily, as they break down over time. Use the chart below to help you make up only the quantity you expect to need for the day. Never combine chlorine bleach with ammonia-containing products.
|Household Task||Add This Much Bleach…||…to This Much Water|
|Routine Kitchen Disinfection||½ tablespoon||½ gallon|
|Small Quantity||¼ tablespoon||1 quart|
|Routine Bathroom Disinfection||½ tablespoon||½ gallon|
|Small Quantity||¼ tablespoon||1 quart|
|Disinfecting Surfaces against Flu virusesi||2 tablespoons||½ gallon|
|Small Quantity||1 tablespoon||1 quart|
|Disinfecting Surfaces against Norovirusii||3 tablespoons||½ gallon|
|Small Quantity||1 1/2 tablespoons||1 quart|
Joan B. Rose, PhD, is the Homer Nowlin Chair in Water Research at Michigan State University and a member of the Water Quality and Health Council.
iWhen disinfecting against flu virus, leave disinfecting solution on surface for 10 minutes, then rinse.
1Yang, H., Kendall, P.A., Medeiros, L. and Sofos, J.N. (2009). Inactivation of Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Typhimurium with Compounds Available in Households. Journal of Food Protection, v. 72, No. 6, pp. 1201-120ne8.
iiWhen disinfecting against norovirus, air dry after applying disinfecting solution. If object is intended for food or mouth contact, rinse with plain water before using.