Most of us have heard it: if you drop food on the floor, it’s still okay to eat it, as long as you act quickly and pick it up within five seconds of it hitting the ground. But does the so-called “five-second rule” have any scientific backing? Anecdotally, most of us would agree—it depends on the kind of food. I’m more likely to eat a cracker that I’ve dropped on the floor than I am, say, a buttered bagel that lands spread-side down. But does timing also make a difference? Is there really a delay or grace period before which germs can find their way to your fallen food?