Q. In your column you said that warm water is no more effective than cold for removing germs. You are way off the mark.
We wash to remove germs, not kill them. Dirty hands are oily and oils are more soluble in warm water. So is soap. Warm water works faster and is more effective than cold water for rinsing off germs. Even my third-grader knows better than you.
A. Several other also readers took us to task for suggesting that warm water is no more effective than cold for removing germs. To try to get a more objective answer, we checked with Charles Gerba, PhD, Professor of Environmental Microbiology at the University of Arizona. He is one of the country’s leading researchers on germ contamination.
Dr. Gerba told us that he has “not seen studies comparing hot vs. cold water for hand washing. Warm water might be somewhat more effective, but the difference is probably so small as not to make much difference. Washing is too quick for the heating to kill much or the soap to dissolve better.”
To wash hands well, wet the hands, apply soap and rub the hands together vigorously for 15 to 20 seconds. Then rinse the lather off thoroughly.
