Almost everyone has dropped some food on the floor and still wanted to eat it. If someone saw you drop it, he or she might have yelled, "5-second rule!" This so-called rule says food is OK to eat if you pick it up in 5 seconds or less.

Believe it or not, scientists have tested the rule. We're sorry to report it's not necessarily true. Bacteria can attach itself to your food even if you pick it up super-fast. But will your dropped food contain enough bacteria to make you sick? It's possible — and that's why you shouldn't eat food that has hit the floor.

Here's what you need to know about the 5-second rule:

1. A clean-looking floor isn't necessarily clean.
   A floor that looks dirty is usually worse, but even dry floors that look clean can contain bacteria. Why? Some germs can survive on the floor for a long time. And unless you have a powerful microscope, you can't check to see how many germs are there. So chances are, some bacteria are probably living on your kitchen floor and the cafeteria floor at school.
2. Faster is better.
   A piece of food will pick up more bacteria the longer it spends on the floor. So food left there for 5 seconds or less will probably collect fewer bacteria than food sitting there for a longer time.
3. Fast may not be fast enough.
   Bacteria can attach to your food as soon as it hits the floor. That means food left on the floor for an instant can get contaminated if conditions are right. And foods with wet surfaces, like an apple slice, can pick up bacteria easily.
4. When in doubt, toss it out.
   Some bacteria are not harmful. But others can give you awful stuff, like diarrhea. You can't see the bacteria and, even if you could, it doesn't take much to make you sick. So what are you to do with that delicious piece of whatever that just slipped from your grip? The safest choice is to throw it out. Or give it to your brother. Just kidding!

Reviewed by: Steven Dowshen, MD
Date reviewed: October 2010