We know that every surface we touch is populated with countless microbes. Most are harmless, but a handful can make us very sick. That’s the logic behind the hand sanitizer habit, trying to stay one step ahead of any pathogenic bugs lingering on grocery carts, light switches and hotel remote controls. Some researchers blame the proliferation of antibacterial hand sanitizers and harsh home cleaning products for an explosion in childhood allergies and asthma. n the United States, there was an 18 percent increase in food allergies among kids in the short period from 1997 to 2007.