Does the Five-Second-Rule Really Work?

Little Timmy is craving some sugar, so he goes to the kitchen and reaches for the cookie jar. A sudden noise distracts him and his beloved chocolate chip cookie falls to the floor. But Timmy is a firm believer in the five-second rule, and he sees nothing wrong with quickly picking up the cookie and stuffing his face to satisfy his sweet tooth.

Timmy may seem rather impulsive, but it’s not unusual for children and adults alike to be guilty of eating food that has been on the floor for less than five seconds, believing it is relatively germ-free.

There are even popular variations of the five-second rule, including the ten-second rule often imposed as a joke by people who are drunk and too intoxicated to react to fallen food in just five seconds. And then there’s also the popular camp variation that states that food can be eaten as long as the bugs don’t get to it first. Yuck.

These may seem like weird superstitions, but many people believe that gastric acid enzymes found in the stomach are strong enough to destroy the “small, harmless” amount of bacteria that could gather on a piece of food in five seconds. But are these bacteria really harmless?

In 2003, Jillian Clarke, then a high school senior, decided she wanted to find out. During an internship at the University of Illinois at Urbana-Champaign, she and a doctoral candidate, Meredith Agle, took swab samples from floors all over the campus, including labs, hallways, and bathrooms, and found that the amount of bacteria on the floors was very low. When she published her research, she concluded that if a piece of food falls on a relatively clean floor, the five-second rule is, in fact, applicable.

However, Clarke’s conclusion has been met with some raised eyebrows. According to WebMD, there are at least ten types of bacteria, such as E. coli, that can cause foodborne illnesses with diarrhea, fever, and flu-like symptoms. These bacteria can also be transferred from floor to food in a split second.

Restaurants also consider the five-second rule moot, and not just when the health inspectors are around: it’s common practice for food that comes into contact with floors, or countertops, to be trashed, even if it’s an expensive steak dinner.

According to nutritionists, recently cleaned floors are still dirty from the bottoms of shoes, and while newly scrubbed countertops are free of bacteria, they are not free of the chemical used to kill the bacteria, which could also be harmful to diners.

The five-second rule isn’t anything new. In fact, the old wives tale may date back to the days of thirteenth century Mongolian ruler Genghis Khan! According to legend, when Khan prepared banquets for his generals, if food fell to the floor, it could stay there as long as Khan allowed and still be eaten, because if the food itself was worthy enough to be prepared for Khan, then it would be worthy to eat no matter how long it was on the floor.

Because of its persistence over the last several centuries, it doesn’t look like the five-second rule is going to go away any time soon. But the next time little Timmy drops a cookie, he may want to think twice before shoving it in his mouth.

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