07 June 2017

Hand washing works whether the water's hot or cold

The finding that you don't need hot water to effectively clean your hands runs counter to current FDA guidelines.

You don't need to scald your hands to get rid of germs. For effective hand hygiene, water temperature matters less than time, new research states.

The finding runs counter to guidelines recommending that food establishments and restaurants deliver water at 37.7°C for hand washing, the researchers said.

The study appears in the Journal of Food Protection.

The cheapest vaccine ever

The new finding will encourage more people to wash their hands – even just with cold water. A new global survey has found that only one in every twenty people washes their hands properly, and South Africans are no exception. Although South African adults are worried about infectious diseases, they still don't wash their hands properly.

And, according to Sourh African public health specialist, Dr Lehlohonolo Majake-Mogoba, proper hand washing is the single most important preventive measure that South Africans can take to improve their health; in fact, it may be the cheapest vaccine ever.


In 2014 SA Health Minister Dr Aaron Motsoaledi, in partnership with the Consumer Goods Council of South Africa (CGCSA), launched the Public Hand Hygiene Campaign in a move to raise awareness on the importance of hand-washing in the prevention of infectious diseases such as Ebola.

Temperature doesn't matter

Scientists at Rutgers University in New Jersey said they found that cold water is as effective as hot in getting rid of harmful bacteria and other germs. What's more important, they said, is that people scrub their hands with soap for at least 10 seconds.

"People need to feel comfortable when they are washing their hands, but as far as effectiveness, this study shows us that the temperature of the water used didn't matter," said Donald Schaffner, a specialist in food science at the university.

And, using cold water saves more energy than warm or hot water, Schaffner pointed out.

"Also, we learned even washing for 10 seconds significantly removed bacteria from the hands," he said in a university news release.

According to a Health24 article, if the answer to the question "How often do you wash your hands?" is "Less than seven times a day", you are failing in basic hygiene. And it's not just how  often you do it, but how well.

A policy change is in order

For the study, the researchers contaminated the hands of 21 volunteers with high levels of a harmless bacteria several times over six months. The participants were then asked to wash their hands in 60°, 79° or 100°C water.

The amount of soap the people used didn't affect the findings. The researchers noted that more study is needed to determine exactly how much soap and what types are best for removing potentially harmful germs.

Referring to the FDA guidelines for the food service industry, Schaffner said their findings suggest a policy change is in order.

"Instead of having a temperature requirement, the policy should only say that comfortable or warm water needs to be delivered," he said. "We are wasting energy to heat water to a level that is not necessary."

Read more:

Did you wash your hands?

SEE: Clean hands can prevent flu

Should patients remind health workers to wash their hands?


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