Well the water may not directly kill germs but warmer water aids in reverse soaponification which removes more grease which is how we rid our hands of germs, by washing them away with our hand oils. Does this study test the cultures from the hands exposed to the same conditions? Does it look at human behavior to find out if warmer hands cause people to wash thair hands longer? If not I find it highly dubious.
schultzy @ http://www.greatbasinindustrial.com/