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Testing the Five-Second Rule

At some time or another, with or without witnesses present, we’ve all used the five-second rule to justify eating a cookie that’s touched the floor. After all, everyone knows that if a tasty treat spends less than five seconds on the ground, it doesn’t collect germs.

Well, not exactly. In 2003, high school student Jillian Clarke performed the first known scientific tests on the five-second rule. While interning at the food science laboratory at the University of Illinois at Urbana-Champaign, Clarke tested the theory by placing gummy bears and cookies on ceramic tiles contaminated with E. coli.

Her results revealed bad news for clumsy snackers: The munchies picked up the bacteria within the five-second window. Clark’s quirky experiment inspired other food researchers to further investigate the matter. One such scientist, Dr. Paul L. Dawson of Clemson University, showed that food actually follows a “zero-second rule,” meaning that bacteria such as salmonella transfer onto food instantly upon contact.

Thankfully, the news isn’t as dire as it sounds. In a follow-up set of experiments, Clarke tested the bacteria levels of the university’s floors. Her team found very little contamination, even in the most highly trafficked areas of campus. As it turns out, most floors at the University of Illinois are so clean you can eat off of them.

[by Ethan Trex]