Joanna Hayden, PhD, CHES

A study published in the Journal of Food Protection looking into the effectiveness of handwashing with cold water vs hot/warm found cold water just as effective at removing bacteria as hot/warm water.

Summary of the journal article: http://www.medicalnewstoday.com/articles/317712.php

Journal article abstract: http://jfoodprotection.org/doi/10.4315/0362-028X.JFP-16-370?code=fopr-site

Use this news

This study challenges the long held belief that warm/hot water is needed for handwashing to effectively remove bacteria. As it turns out, cold water works just as well and washing hands for as little as 10 seconds does a decent job.

As far as antibacterial soap goes, according to the results of this study, it wasn’t that much more effective than using regular soap. Given the rising problem with antibiotic resistant bacteria, it’s best to avoid using it.

We all know that handwashing helps prevent infections, but the Centers for Disease Control (CDC) reminds us that:

  • Handwashing helps prevent diarrhea, respiratory infections and may even help prevent skin and eye infections because:

                     Bacteria, viruses and other disease causing germs get  
                      into the body through the eyes, nose and mouth
                      without us realizing it when we touch our faces with
                      our hands.

                      Bacteria, viruses and other disease causing germs
                      from unwashed hands can get into food and drinks
                      when people prepare or consume them. Some can
                      multiply in certain types of foods or drinks, under
                      certain conditions, and  make people sick – for
                      example botulism or salmonella.

                        Bacteria, viruses and other disease causing germs
                        from unwashed hands can be transferred
                        to objects, like handrails, table tops, or toys, and
                        then picked up by another person’s hands.

  • Handwashing not only keeps us individually healthier, it helps keep our communities healthier too.    

                               Reduces the number of people who get sick with
                               diarrhea by 31%
                                Reduces diarrheal illness in people with
                                weakened immune systems by 58%
                                Reduces respiratory illnesses, like colds, in the
                                general population by 16-21%

  • Remember to wash your hands:

                     Before eating food
                     Before, during, and after preparing food
                     Before and after caring for someone who is sick
                     Before and after treating a cut or wound
                    After using the toilet
                    After changing diapers or cleaning up a child who has                         used the toilet
                     After blowing your nose, coughing, or sneezing
                     After touching an animal, animal feed, or animal                                 waste
                     After handling pet food or pet treats
                     After touching garbage

  • To properly wash your hands, the CDC recommends the following:

  1. Wet your hands with clean, running water (warm or cold), turn off the tap, and apply soap.
  2. Lather your hands by rubbing them together with the soap. ...
  3. Scrub your hands for at least 20 seconds. ...
  4. Rinse your hands well under clean, running water.
For more information:

Centers for Disease Control – How and When to Wash Your Hands

Mayo Clinic – Handwashing Do’s and Don’ts



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