Not Hot Enough

THE CLAIM
Always wash your hands with hot water,not cold.
THE FACTS
Soap and warm water have long been said to prevent the spread of infections,but is warm or hot water really more effective than cold?
In its medical literature,the Food and Drug Administration of the US states that hot water comfortable enough for washing hands is not hot enough to kill bacteria,but is more effective than cold water because it removes oils from the hand that can harbour bacteria.

But in a 2005 report in the Journal of Occupational and Environmental Medicine,scientists pointed out that in studies in which subjects had their hands contaminated,and then were instructed to wash and rinse with soap for 25 seconds using water with temperatures ranging from 4.45 degrees Celsius to 49 degrees,the various temperatures had no effect on transient or resident bacterial reduction.
They found no evidence that hot water had any benefit,and noted that it might increase the irritant capacity of some soaps,causing contact dermatitis. Temperature of water used for hand washing should not be guided by antibacterial effects but comfort, they wrote,which is in the tepid to warm temperature range. The usage of tepid water instead of hot water also has economic benefits.
THE BOTTOMLINE
Hot water for hand washing has not been proved to remove germs better than cold water.
_ANAHAD O8217;CONNOR,NYT