"Only about 60 percent of people who use the public restroom wash their hands," Gerba says. "Only half of those actually use soap, and only half of those people wash for the 20 seconds or more the Centers for Disease Control and Prevention recommends."

When he travels, Gerba takes along disinfectant wipes to clean his hotel room’s TV remote and telephone—among the grimiest objects, his studies show. On car trips, he packs a blanket for roadside picnics; rest stop tables, he says, are magnets for bird droppings. And for those times when you can’t wash your hands, Gerba suggests tucking a bottle of hand-sanitizing gel in your pocket or purse and using it frequently, especially before meals or snacks. The alcohol in the gel kills most skin germs on contact.