Scientists Weigh In on the 5-Second Rule

URBANA–High-school student Jillian Clarke investigated the scientific validity of the “5-second rule” during her apprenticeship in Hans Blaschek’s University of Illinois lab this summer. You know the rule: If food falls to the floor and it’s in contact with the floor for fewer than 5 seconds, it’s safe to pick it up and eat it.

According to Clarke, a senior at the Chicago High School for Agricultural Sciences, the 5-second rule dates back to the time of Genghis Khan, who first determined how long it was safe for food to remain on a floor when dropped there. Khan had slightly lower standards, however; he specified 12 hours, more or less.

Among Clarke’s findings:

–Seventy percent of women and 56 percent of men are familiar with the 5-second rule, and most use it to make decisions about tasty treats that slip through their fingers.

–University floors are remarkably clean from a microbial standpoint.

–Women are more likely than men to eat food that’s been on the floor.

–Cookies and candy are much more likely to be picked up and eaten than cauliflower or broccoli.

–And, if you drop your food on a floor that does contain microorganisms, the food can be contaminated in 5 seconds or less.