Q. With flu season and MRSA staph infection upon us, we are urged to wash our hands frequently, usually “with warm soapy water.” My memories of Bacteriology 101 some 50 years ago aren’t crystal clear, but I can’t recall that “warm” water kills anything. Soapsuds, on the other hand, do carry nasty things away. Is there any science behind the “warm water” suggestion?
A. You are absolutely right that warm water is no more effective than cold for removing germs. Soap and water don’t kill germs but only wash them off the surface of the skin.
If we had to guess, we would venture that it is far more pleasant to stick your hands in warm water than ice-cold water. The longer you wash and rinse, the more effective the process. Sing the alphabet song as you wash to get the timing right.
As it is, few people wash their hands as often as they should (after using the bathroom, before eating, after coughing or sneezing and so on).
This is a particularly serious problem in hospitals, where it is often difficult to get health care workers of all kinds to wash hands between patients. A worker who fails to wash can take germs from one patient and give them to the next.