Thursday, June 21, 2007

A Little Insight on the "Five Second Rule"

I read this on Ask Yahoo! this morning and I couldn't resist posting:


Dear Yahoo!:
Is there any truth to the "five second rule" about food that falls on the floor?


This piece of folk wisdom maintains it's hygienically safe to eat food dropped on the ground, provided it's been there no longer than five seconds. Generations of school kids have pleaded "the Five," popping potato chips into their mouths after swiping them off the floor.

But is this maxim, first codified by Genghis Khan who used a 20-hour limit (the steppes of central Asia being so immaculate), actually true? For disappointed butterfingers, two experiments provide somewhat inconclusive guidance.

The first, at the University of Maine, counted the number of bacteria clinging to various downed eats. Results? Contrary to what you might expect, the number of bacteria on "wet" foods like cheese actually decreased the longer the food was on the floor, seemingly making five seconds too short a time for wet foods, rather than too long.

In another study, a Chicago high-school student won an Ig Nobel Award after measuring the bacteria on Gummy bears and cookies dropped around a university campus. Astoundingly, she found the floored food was relatively bacteria-free. However, when she deliberately exposed the food to floor tiles inoculated with E. coli, contamination did indeed occur within five seconds. Foods with higher levels of naturally occurring microflora, such as meat, cheese, and vegetables, attracted the germs fastest.

So the rule is really in the eye of the beholder. Though most observers seem to think it wishful thinking at best, the particularly hungry might want to consider where the food was dropped, the relative food wetness of the food and the floor, etc. But more importantly -- is anyone watching?

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