Don't bother turning on the hot-water tap when washing your hands, scientists say: cool water is just as effective at killing bacteria.
A new study from Rutgers University shows the temperature of water doesn't matter when it comes to getting rid of harmful bacteria from people's hands.
What does matter, the study found, is timing: even just 10 seconds significantly removes bacteria from the hands. Whether the amount of soap and the type of soap used plays any role in killing microbes on the hands is still being studied.
The finding could have implications on water energy, since cold water uses less energy than hot or warm water. Currently, federal guidelines recommend that restaurants and food establishments deliver water at 100 degrees Fahrenheit for handwashing.
The FDA issues its guidelines to states every four years.
The Rutgers study consisted of 21 participants, who were asked to wash their hands in 60-degree, 79-degree or 100-degree temperatures using 0.5 ml, 1 ml or 2 ml volumes of soap over a period of six months.