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Is the “Five-Second Rule” a Myth?

bacteriaHarold McGee, also known as the New York Times’ “Curious Cook,” has an article about a new paper from a Clemson University research group led by Paul Dawson on the validity of the “five-second rule” — the old adage that if you drop food on the floor but pick it up within five seconds, it’s okay to eat it. According to a 2003 survey conducted by Jillian Clarke (a high-school intern at the University of Illinois who later won an Ig Nobel Prize for her research), more than 50% of adult men and 70% of adult women knew of the five-second rule, and many said they followed it. Now the Clemson researchers have gathered data to assess its validity once and for all. The results? According to McGee:

On surfaces that had been contaminated eight hours earlier, slices of bologna and bread left for five seconds took up from 150 to 8,000 bacteria. Left for a full minute, slices collected about 10 times more than that from the tile and carpet, though a lower number from the wood.

A definitive answer! It works! Sort of! That is, there’s no guarantee that the 150 to 8,000 bacteria gained in those five seconds are safe for consumption. As such, McGee proposes that the rule be revised as follows:

If you drop a piece of food, pick it up quickly, take five seconds to recall that just a few bacteria can make you sick, then take a few more to think about where you dropped it and whether or not it’s worth eating.