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Bacteria in the washroom: A dirty combination

September 19, 2010
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Public washrooms are generally perceived as places rife with potential for cross-contamination of germs and bacteria.

A recent survey found that more than 90 percent of restroom users perform some sort of “bathroom gymnastics” to avoid making any contact with their skin and surfaces in a public restroom.

Easing users’ fears
Standing water, filled trash bins, clogged sinks or toilets, empty paper towel dispensers, and unkempt conditions all contribute to the problem.

For those people responsible for maintaining washrooms, an emphasis on wet areas will help alleviate the potential for cross-contamination.

Restricting the movement of water around the washroom — either by manual cleaning and disinfection of wet surfaces, promoting proper hand washing and drying, or by using hands-free devices — can reduce the number of sites where bacteria can survive.

Those who use the washroom can also protect themselves and reduce the risk of cross-contamination by thoroughly washing and drying their hands and avoiding contact with wet surfaces.

Study findings
NSF International, formerly the National Sanitation Foundation, is an independent, non-profit organization committed to public health protection.

NSF recently conducted a study of public washrooms across the United States.

In the study, washroom hand-contact surfaces, such as faucet or flush handles, soap dispensers, doorknobs and latches, and paper towel dispensers, were evaluated for microbiological content.

The study found detectable concentrations of aerobic bacteria on nearly 86 percent of the surfaces sampled.

The highest microbial counts were detected on surfaces that are generally wet or damp.

The faucet handles and soap dispensers sampled in the study had an average of over 100,000 bacteria per square inch.

In some cases, microbial concentrations exceeding 1 million bacteria per square inch were detected.

Additionally, six out of 20 soap dispenser samples showed coliform bacteria, four of which were encountered within 24 hours of the site being disinfected.

Coliform bacteria comprise a subset of lactose fermenting, gram negative bacteria, which includes pathogens such as E. coli and Salmonella.

The total coliform count is widely used as an indicator of hygiene and may suggest the presence of fecal contamination in the locations where they are found.

A high incidence of Staphylococcus aureus bacteria were found on paper towel dispensers.

Staphylococcus aureus is generally found on the skin and is commonly removed during hand washing and drying.

According to the Centers for Disease Control and Prevention (CDC), keeping hands clean is one of the most important steps to avoid getting sick and spreading germs to others.

Furthermore, the U.S. Food and Drug Administration (FDA) estimates that proper hand washing could eliminate half of all cases of foodborne illness.

Interesting findings
Ironically, the NSF washroom study found the highest concentrations of bacteria in the washrooms on items associated with hand washing, such as faucet handles, soap dispensers and paper towel dispensers.

After washing their hands, restroom users are leaving their germs behind.

This can contribute to conditions where people become the conduit for cross-contamination, transferring bacteria on their skin to other surfaces they touch.

An emphasis on keeping hands and washroom surfaces clean and maintained is vital in reducing the threat of cross-contamination of germs and bacteria from public washrooms.

According to the CDC, simple washroom cleaning is not enough.

Surfaces may look clean, but infectious germs can live and thrive on surfaces for hours and even days.

The use of disinfectants along with cleaning actually destroys germs and provides an extra level of protection from germs and cross-contamination.

Disinfectants are registered with the U.S. Environmental Protection Agency (EPA) and have a unique EPA registration number.

Target area
The NSF study found the highest incidence of microbial counts on wet surfaces, which makes sense since most microorganisms thrive in moist, humid environments.

Soils and skin particles washed away during hand washing provide a source of nutrients for most microorganisms.

Maintenance efforts geared toward cleaning and disinfecting surfaces that are commonly wet, such as sinks and faucets, are an important first step in reducing the incidence or threat of cross-contamination.

Similarly, restroom users who thoroughly dry their hands after washing can also reduce the chance of cross-contamination.

Wet hands can transfer as much as 1,000 times more bacteria onto surfaces as dry hands and the moisture left behind can aid to prolong the survival of the microorganisms left behind.

Facilities that offer adequate hand drying facilities will help to reduce the likelihood of cross-contamination.

Many product manufacturers are now offering touchless toilets, water faucets, soap dispensers, paper towel dispensers and automatic hand dryers.

These devices are equipped with automation and sensors to help reduce the incidence of hand-borne cross-contamination, while reducing the need for washroom users to perform “bathroom gymnastics.”

Setting the standard
Older hand dryers simply suck in dirty restroom air, heat it up and blow it back onto a user’s hands, leaving hands damp and more prone to spread bacteria.

NSF’s Protocol P335: Hygienic Commercial Hand Dryers establishes health and sanitation requirements for hygienic hand dryers.

This includes requiring hand dryers to dry hands completely within 15 seconds using air filtered with high-efficiency particulate air (HEPA) filtration as well as additional requirements for hands-free operation, water disinfection, resistance to burns, product cleanability and noise levels.

“With the development of NSF P335, hand dryer manufacturers, their customers, as well as the operators of public restrooms can now verify to the public that their products have met appropriate sanitation requirements and people can quickly and safely dry their hands as well as thwart recontamination by using warm, clean, filtered air,” says Bob Ferguson, vice president of NSF International.

According to Ferguson, NSF recently recognized a new hand dryer manufactured by Dyson as the first and only hand dryer to be certified by NSF International to NSF Protocol P335.

Dyson’s dryer is activated by a touchless infra-red sensor technology and has anti-microbial additives integrated into its surface to reduce bacterial and fungal growth.

Other benefits of hand dryers
The use of commercial hand dryers also reduces the demand for paper towels, which in turn reduces the amount of waste in washrooms.

Addressing opportunities for cross-contamination in public washrooms is key.

Health advocacy agencies stress the link between personal hygiene and good health.

Manufacturers of washroom accessories are addressing cross-contamination concerns by offering products which are designed for and operate to promote good hygiene.

They can even reduce operational expenses in the long run.

A washroom without filled trash bins and standing puddles of water on countertops and floors demonstrates a facility manager’s commitment to cleanliness and personal hygiene.

These actions, working together, can reduce the opportunity for the transfer of pathogenic organisms that can make people sick.



Patrick Davison is senior project manager, Engineering and Research Services, NSF International.

Robert Donofrio, M.S., Ph.D. candidate, is director of Microbiology and Molecular Biology, NSF International.
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