The 5-Second Rule and Fallen Food: Fact or Fiction?

The short answer from a registered dietitian
ice cream cone dropped on floor

Q: That treat that you’ve been craving just slipped through your fingers and hit the floor. Can you eat it without worry if you scoop it up within five seconds?

A: Maybe — but do you really want to risk it?

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Food that lands on the floor will pick up some bacteria. That is a fact. But will that contamination be enough to give you gastric regret? That’s the question at the heart of the debate concerning the “5-second rule.”

To start, the concept behind the rule about eating dropped food is solid. The less time food spends on the floor, the fewer bacteria it picks up. Kind of common sense, right?

But the 5-second rule “is a significant oversimplification of what actually happens” regarding bacteria transfer from floor to food, according to a 2016 study published in an American Society for Microbiology journal.

Just consider all the variables. The type of food fumbled is significant, as is the surface the food hits. Time on the floor is only one part of the equation.

So let’s look at these factors.

On the food front, moistness matters —  and it matters a lot. A juicy slice of watermelon basically serves as a bacteria sponge once it hits the ground. Expect it to potentially soak up nastiness such as E. coli and staph infection.

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Drop a hard pretzel on the floor, however, and there’s far less reason to worry.

(An interesting side note: People are more willing to eat cookies and candy off the floor than veggies such as cauliflower or broccoli, according to a much-cited research project at the University of Illinois.)

When it comes to floor surfaces, carpet is the safest for a pick-it-up-and-eat move as the fibers hold less bacteria. Tile is riskier. Wood flooring? That’s tougher to nail down given all the different types and finishes.

Consider the location, too. Let’s just say eating something off of your living room carpet seems like a better bet than grazing off of a high-traffic gas station restroom.

Again, common sense.

So back to the 5-second rule and the main question: Should you eat that dropped doughnut or consider it a sacrifice to the god of clumsiness? Researchers come down on both sides of the debate.

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Where everyone finds common ground, however, is on the seriousness of foodborne illnesses.

Consider this: An estimated 48 million Americans will get sick from a foodborne disease this year, according to the Centers for Disease Control and Prevention. Nearly 130,000 will be hospitalized. Roughly 3,000 will die.

That’s a stomach-churning reality — and definitely something to think about before nibbling off a floor buffet.

Dietitian Beth Czerwony, RD

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