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Bacteria on the Skin and Why We Should Wash Our Hands

Linda Crampton is a writer and former teacher with a first-class honors degree in biology. She writes about the scientific basis of disease.

Bacteria in Our Environment

All day long, our hands touch different objects. These objects are usually covered by microscopic bacteria. The bacteria contaminate our hands and enter our body when we touch our nose or mouth. Many of the microbes are harmless, but some are dangerous. Our immune system is often able to destroy the harmful bacteria. Sometimes, however, the immune system is overwhelmed by the microbial invaders and we become ill.

Since it's hard to avoid potentially harmful microbes in the environment, it's important that we wash our hands regularly. This is especially true when performing an activity that has a high chance of bacterial transfer—such as using a washroom—or after touching an object that's likely to have dangerous microorganisms on its surface.

A safety routine is needed in public washrooms.

A safety routine is needed in public washrooms.

Hand washing is considered to be a very important aspect of hygiene. An international coalition of government, scientific, and private organizations has held a Global Handwashing Day on October 15th of every year since 2008.

Fecal Contamination of Hands

Fecal bacteria can be transferred from one person to another by unhygienic washroom procedures. Bacteria can also be transferred from a person's rectum to another part of their body by lack of hygiene. To many people, washing their hands after using a washroom is an automatic activity that they would never consider omitting. Research has shown that a surprising number of people don't wash their hands after using a toilet, however.

In a UK research project, electronic recording devices in gas station washrooms provided interesting and scary data. Although 99% of the people interviewed said that they had washed their hands after using the washrooms, the recording devices showed that only 64% of the women and 32% of the men had actually turned on the faucet to wash their hands.

Fairly similar results were discovered at three Minnesota state fairs. Observers recorded hand washing in male and female washrooms. The percentage of hand washers at the three fairs were 64%, 65% and 75% for females and 30%, 39% and 51% for males.

Some researchers acknowledge that they need to do more specific research to study hand washing percentages after urination compared to those after defecation. Some also want to determine if the assumption that hand washing after urination is less important for males than for females is actually valid.

Public washrooms often contain potentially dangerous bacteria.

Public washrooms often contain potentially dangerous bacteria.

Washroom Hygiene

Many experts suggest turning off the faucet in a public washroom with a paper towel instead of with a hand. Some suggest using the towel to open the door before leaving the washroom and discarding the towel after this is done. Another common suggestion is to use an elbow instead of a hand to press the handle of a paper towel dispenser. An ideal washroom has a no-touch toilet flush, no-touch faucets, and a no-touch hand dryer, but not all washrooms are ideal.

It's a good idea to stay as far away from a toilet as possible as it flushes. Health experts often recommend that we put the lid of a home toilet down before we flush, since tiny particles of fecal matter containing bacteria and viruses enter the air during the flush.

Fecal Contamination of Other Items

Fecal bacteria are definitely being transferred out of washrooms. In one study, hygiene experts in the UK discovered that 26% of the tested hands were contaminated with fecal material and 11% were grossly contaminated. The researchers also found that 14% of paper money and 10% of credit cards in their sample were contaminated with fecal matter.

Earlier research found that one in six cell phones were contaminated with fecal matter containing strains of E. coli that are known to be associated with severe stomach cramps, nausea, vomiting, and diarrhea.

Paper money and coins are contaminated with bacteria.

Paper money and coins are contaminated with bacteria.

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A 2014 study by researchers at New York University found DNA from 3,000 bacterial species on dollar bills.

What Items Have the Most Bacteria on Their Surface?

Almost any item has bacteria on its surface, unless it has been sterilized and kept in a sterile environment. However, certain objects are more likely to contaminate our skin than others.

There are many situations in which our hands can pick up possibly dangerous bacteria. Hygiene procedures while using a toilet and touching the toilet parts are major sources of fecal contamination on the hands. Other ways to pick up microbes include touching objects such as:

  • door handles and knobs
  • faucet handles
  • shopping cart handles
  • handles of paper towel dispensers in washrooms
  • railings and the handrails of escalators
  • elevator buttons
  • telephones and cell phones
  • paper money and coins
  • grocery and credit cards
  • computer keyboards
  • light switches
  • dishcloths
  • kitchen sinks
  • toys
  • diapers
  • items contaminated by nasal discharge, saliva, vomit, animal or human waste, or soil
  • contaminated food and water

Harmful bacteria may also be found on kitchen countertops, in refrigerators, and on work desks.

Escalator handrails have bacteria on their surfaces.

Escalator handrails have bacteria on their surfaces.

Does Hand Washing Remove Bacteria?

Researchers at the London School of Hygiene and Tropical Medicine tested whether hand washing with plain water or with soap and water could destroy bacteria that came from feces. Volunteers touched door handles and railings in public places. Their hands were then tested for the presence of bacteria. This procedure was followed multiple times with each of the twenty volunteers.

44% of the samples showed the presence of Enterococcus and Enterobacter, two microbes that are often found in feces and can cause diarrhea. Washing the hands with water alone reduced the percentage of samples with the two kinds of bacteria to 23%. Washing the hands with water and plain soap reduced the samples with bacteria to 8%.

Washing the hands with soap removes many harmful bacteria.

Washing the hands with soap removes many harmful bacteria.

How to Remove Germs in Hand Washing

Some people may think it's strange to be told how to wash their hands, since they've been doing it all their lives and it seems like a very simple activity. Hygiene experts are serious in their attempts to get us to wash our hands in the best possible way to kill bacteria and other germs, however.

All parts of the hand have to be cleaned—the palm, the back, and the fingers. We need to pay special attention to the fingertips and to the area under the fingernails and between the fingers. Rubbing the hands together is very important. Experts also say that we need to wash for at least fifteen to twenty seconds, not counting the rinsing. Two suggestions are to sing "Happy Birthday to You" twice, or "Twinkle, Twinkle, Little Star" once (aloud or in our mind) as we're washing. This could be a fun way to teach children to wash their hands correctly, but it's not a bad idea for adults either.

Plain soap doesn't kill germs, but it does help to remove them from the skin. Soapy water removes both dirt and oil from skin. The friction created by rubbing the hands together while washing with soap is also an important mechanism for removing grime and bacteria.

Soap, water, and friction are considered to be the best tools for washing the hands.

Soap, water, and friction are considered to be the best tools for washing the hands.

The Best Type of Soap

Researchers recommend plain soap over antibacterial soap. Antibacterial soap does kill some bacteria, but it needs to be left on the skin for longer than plain soap in order to have a significant effect. A two minute exposure is necessary, according to the Minnesota Department of Health. They say that plain soap is sufficient and that antibacterial soap isn't necessary.

Some researchers are concerned that the use of antibacterial soaps is increasing the resistance of bacteria to chemicals that are designed to kill them. When an antibacterial chemical attacks and kills bacteria in a species, any individual bacteria that have a gene or genes that give them resistance to the chemical survive and multiply. Eventually, most of the population will be resistant. Frequent use of the antibacterial chemical in a human population could speed up the process.

Liquid soap is sometimes recommended over bar soap, since a microbe population is more likely to build up on a bar of soap. It's important to keep the liquid soap covered to prevent or reduce the entry of bacteria, however.