The Five-Second Rule: To Eat or Not to Eat

Charles Bryant

Welcome to the new Stuff You Should Know blog with Josh & Chuck. The blog is the result of our desire to connect our listeners and site visitors together through some intelligent discussion. We'll introduce interesting and offbeat topics a couple of times a day and see what you people have to say about them -- easy as that. We believe that our listeners are some of the smartest, cleverest people breathing the air of our fair planet and we want to hear from you.

And away we go...

Has anyone ever picked up a piece of food from the floor and eaten it within the socially acceptable five-second time frame? Or perhaps I should ask if anyone has NOT done so. The "five-second rule" is a classic example of a well-entrenched social code. But is there some science behind the truth of the matter? Turns out there have been some studies.

Michael Feldmans, on his radio show "Whad'ya Know?" interviewed a Clemson University researcher who tested dropped food on carpet and tile floors infected with salmonella. He found that 1,000,000 bacteria jumped onto a slice of bologna in five-seconds. You'll be glad to know that the dryer foods fared better, and the tile floor didn't deliver as much bacteria as the carpet. The researcher also claims that Genghis Khan was reportedly known for having an official dropped food rule of his own, but it was most certainly longer than five seconds.

NPR talked to a Chicago high school student who did some testing of her own with e-coli and got similar results. But what about your ordinary, non-bacteria spiked floor? The University of Connecticut tackled that one and found that it takes as long as 30 seconds -- so you're safe as long as your floor isn't coated in salmonella or e-coli.

Your homework for tonight:

How can intestinal bacteria like E. coli infect a vegetable like spinach? How Food Cravings Work Did Genghis Khan really kill 1,748,000 people in one hour?