Contaminated Soap Can Spread Bacteria

Wash your hands and watch bacteria spread. That doesn’t sound good, but a new study revealed that all the soap dispensers at an Ohio school were contaminated with bacteria that cause illness. After kids used the soap, microbe levels on their hands grew.

MSNBC quotes microbiologist Carrie Zapka:

“This is kind of counterintuitive because soap is supposed to clean you. That soap can be a source of bacteria that can spread beyond the person washing his hands.

“There’s no need to panic. I want people to wash their hands because hand washing is proven to be effective at preventing sickness. We don’t know what the true risk level is in the community.”

Hospitals use dispensers that have replaceable bags or cartridges with their own nozzle and are sealed to prevent contamination. Many public bathrooms use refillable dispensers that are rarely cleaned.

In the lab, researchers put two common species of bacteria that have caused infectious outbreaks into soap and tested two hand washing techniques. The first hand washing method is the full version that doctors do, and the second is the regular daily hand washing we all do, or should do, anyway.

People who washed with the highly contaminated soap ended up with more bacteria on their hands after washing, in turn transferring more bacteria to items they touched.

Following up with a visit to an elementary school that had the open style refillable soap dispensers, the researchers found all 14 dispensers were contaminated with potentially harmful bacteria. Students and staff who washed with the soap had 26 times more bacteria on their hands than before they washed.

Replacing the dispensers with sealed ones had good results — they were free of contamination a full year later.

“Our findings further show that extrinsic contamination of hand soap can be eliminated or considerably reduced through the use of sealed-soap-dispensing systems,” say study authors.

Hand washing is still one of the best things your can do to prevent common illnesses and promote good health. But you might want to check out the type of dispensers used in public bathrooms.

Zapka works with Gojo Industries, makers of skin health and hygiene products, including soaps and soap dispensers. The study is reported in Applied and Environmental Microbiology

Sources: MSNBC; Applied and Environmental Microbiology, May 2011,p. 2898-2904, Vol. 77, No. 9 0099-2240/11/$12.00+0 doi:10.1128/AEM.02632-10


The Trouble with Triclosan in Your Soap

Ann Pietrangelo is the author of “No More Secs! Living, Laughing & Loving Despite Multiple Sclerosis,” a memoir. She is a member of the American Society of Journalists and Authors and The Author’s Guild, and a regular contributor to Care2 Healthy & Green Living and Care2 Causes. Follow on Twitter @AnnPietrangelo


jane richmond
jane richmond6 years ago

try to avoid bar soap.

Marcia Machado
Marcia Machado6 years ago


Cesar V.
Cesar Villanueva6 years ago

thank you for the information

Annemarie W.
Annemarie L6 years ago

I have been thinking about carrying around a small container of hand soap... That way you know you're not getting soap with tricolsan or contaminants... Maybe I'm going too far?

Brigid C.
Brigid C6 years ago

Who'd have thought you'd get sick from soap!

May Howie
may Howie6 years ago


tiffany t.
tiffany t6 years ago

soap,warm water, and lots of friction. special care between fingers, esp. groove between index finger and thumb, up to and around wrist. completely dry hands. even with hand sanitizer it is the friction of "rubbing until hands are dry" that destroys the cell; what ever it may be. long known fact that bar soap can= petri dish.

Victor R. Machin
Victor Machin6 years ago

There was never a problem with soap contamination in the 50's when I was a kid. In those days we used proper soap containing disinfectant, its name, Carbolic! It did what soap is supposed to do-----Clean & Kill germs! Unlike the stuff of today. Replacing soap dispensers with sealed ones means the use of yet more plastics, which when empty, will no-doubt end up with the rest of the world's plastic waste!------ Floating/submerged in our Seas and Oceans! Where it Kills all manner of marine wildlife! All that is needed, is soap with the (Right!) ingredients.

Chris L.
Chris L6 years ago

These are my questions: What kind of soap was it? Antibacterial? Just hand cleaner? Plain old soap? It makes a difference. I assume that since this "study" was industry/product-sponsored, that the least effective product was studied in order to exaggerate the results.

Lindy E.
Belinda E6 years ago

Okay, this makes no sense. First, we understand that the study was probably sponsored by the makers of Purell, which makes it suspect from the start, but let's set that issue aside for the moment.

Firstly, it implied (but didn't actually say) that both methods of hand-washing gave the same results. Does that seem likely?

Secondly, it doesn't say a thing about rinsing time and methods. As Carole says, rinsing is critical too - the soap only loosens the dirt and bacteria, rinsing then removes them. (And here on Care2, we don't even want to talk about KILLING bacteria, do we?)

Thirdly, the report says that they had 26 times more bacteria after washing than before - but we should nevertheless always wash our hands. SAY WHAT? What on earth is the rationale behind that statement?? Sounds to me as if there's something they aren't telling maybe the makeup of the bacteria colonies, or the exact methods of testing, or something.