Leaving food on eating utensils and dishes could easily cause bacteria to grow on them, especially if it's moist, according to a U.S. study.

"The best thing you can do is wash your dishes off right away, before the food dries," said Melvin Pascall of Ohio State University. "It saves washing time and gets rid of places where bacteria can survive drying and washing."

Pascall and Jaesung Lee found that even when they washed dishes in cooler-than-recommended water, numbers of bacteria on the dishware dropped to levels accepted in the U.S. Food and Drug Administration's Food Code.

They also found that certain foods -- especially cheese and milk -- can be safe havens for bacteria when dried onto dishware. Lipstick, however, proved to be dangerous to bacteria, says Pascall.

When restaurants manually wash dishes, they follow a three-step process: Dishes are washed and scrubbed in soapy water, rinsed with clean water, and finally soaked in water containing germ-killing sanitizers. However, employees often use water that is cooler than 110 degrees Fahrenheit -- the minimum washing temperature recommended -- because it is uncomfortably hot.

The findings are published in the Journal of Food Engineering.