Whoops! You've dropped your sandwich, drumstick, lollypop or Twinkie on the floor. But don't worry. If you pick it up within five seconds, it'll still be safe to eat. Right?
That's the Five-Second Rule. Or maybe you've heard it as the Ten-Second Rule or, in some more permissive and less mysophobic (germ-fearing) societies, "Whatever!"
According to the rule, here's what happens when you drop your food:
The instant the food hits the floor, it becomes a feast for all the floor germs. To them it is manna from microbe heaven -- free food, and the occasion for a big microbe party. The first scout germ that finds the food calls out an invitation to its invidious relatives all over floor: "Come and get it, guys!" Bacteria swarm to the site from all directions and climb or jump onto what to them appears to be Manna Mountain. After a while, the food is swarming with bacteria and unfit for human consumption. One must snatch it back before the germs have had enough time to envelop it completely.
You don't buy that scenario? Well, that's what the Five-Second-Rule devotees apparently believe, in spite of the fact that several hundred years of microscopic examination have failed to detect tiny trampolines or pogo sticks with which bacteria can jump onto a piece of food. Trying to foil them by snatching the food away before the entire flock has had a chance to hop aboard is simply absurd. They don't hop, or even crawl. So no matter how you slice it, any such rule is baloney, or a red herring, or any other food metaphor you like, because the length of time your food rests on the floor has nothing to do with how contaminated it gets. It picks up germs the instant it lands.
Why do some people actually believe this ridiculous idea? Because it makes them feel good.
People want to believe things, no matter how absurd, that make them feel smug. And snatching the food back quickly is psychologically satisfying because it avoids the guilt of having to throw away some perfectly good food when people are starving in [name a country]. And besides, they really wanted that food. Don't you always drop the best part that you were saving for last?
For all the Five-Second disciples out there, let's take a look at what really happens when the food hits the floor:
Floors are a menace because they are likely to harbor pathogenic micro-organisms such as bacteria, viruses, and fungi that can cause human maladies from a tummy ache to anthrax, tuberculosis, typhus, botulism, leprosy and bubonic plague. The germs are living in so-called biofilms -- complex aggregates of microorganisms that grow on surfaces -- on everything from public restroom floors to the immaculate, "you-could-eat-off-it" floors in our own kitchens.
But here's the bottom line: The amount of dirt -- and number of germs -- that sticks to a food depends on only three factors: how dirty the floor is, how big the contact surface is, and how sticky the food is. (Was your lollypop dry or pre-sucked?) Unfortunately, dirt will stick to most foods because they are generally either moist or fatty. And the sticking is instantaneous.
Adam Savage and Jamie Hyneman of TV's MythBusters carefully measured the effect of contact time on the number of germs picked up by food from a contaminated surface. They did it for fun, of course, and got the right answer: Time has nothing to do with it. But other, more "serious" scientists have done similar experiments and, of course, came up with the same result. But a little forethought could have saved them the trouble.
Are you still uncertain about what to do the next time you drop a piece of food? There's always the Derring-Do Dodge: Look around. If nobody saw you drop it and pick it up, just go ahead and... well, I'd better stop there.
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