Ever drop a piece of food on the floor — usually chips or a delicious cookie, or maybe the ingredients for the tacos you're making — and yell, "Five-second rule!" if anyone is around and grab it? Or maybe just think it if you're alone? Do you grab it and dust it off a little?
Is it really okay to eat food that's been on the floor if you pick up within five seconds? The myth contends that if food spends just a few seconds on the floor, dirt and germs won't have much of a chance to contaminate it.
As always, science tells us it's a little bit more complicated than just the time. It actually depends on just how much bacteria can make it from floor to food in a few seconds and just how dirty the floor is.
Dr. Paul Dawson, a professor at Clemson University who has done the only published study on the five-second rule, writes for CNN that he "found that the amount of bacteria transferred to either kind of food didn't depend much on how long the food was in contact with the contaminated surface."
Also interesting? The type of surface matters. "Carpets, for instance, seem to be slightly better places to drop your food than wood or tile," Dawson writes. "When carpet was inoculated with salmonella, less than 1% of the bacteria were transferred. But when the food was in contact with tile or wood, 48-70% of bacteria transferred." Ew.
So, should you eat food that's fallen on the floor (or into the sink, or onto the cutting board you just had raw meat on)? The odds are good you won't get sick, but why risk it? The important thing is to keep the space you prepare your food clean, as well as your cooking tools.