Should You Use the 5 Second Rule?

(Last Updated On: May 26, 2020)

Should You Use the 5 Second Rule?

Unless you have some kind of godlike ability to never drop food, some of yours has probably ended up on the floor. And depending on who you or your friends are, you might have been told to heed the fabled 5 second rule. Perhaps you were more prone to doing so because the food you dropped was really expensive, or really good. Or, you’re just a maniac who uses the 5 second rule to justify eating food off of the floor. But, should you use the 5 second rule in the first place?

Should You Use the 5 Second Rule?

It turns out, a lot of people have looked into the 5 second rule, and it’s actually been… A point of research contention. We’ll get more into it later, but a major 2006 study claimed that food was contaminated almost immediately, while later studies as recently as 2016 have tried to debunk such claims.

Anyway, you might be wondering who actually abides by the 5 second rule. There aren’t a lot of official polls–most of them are those kind of “just for fun” things you see floating around. 

Regardless, a British poll in 2017 found that 58% of Brits were perfectly okay eating food off of the floor if they dropped it at home. Though only 16% stood by the 5 second rule. However, a combined 23% was okay with eating food off of the ground if it was on the ground for less than 5 seconds (they were okay with anywhere between just 1 second and 4 seconds). 32% responded “I’m not eating off the floor,” and 19% were okay with eating food off of the ground if it was there for over 10 seconds.

A 2003 study out of the University of Illinois found that most Americans were willing to abide by the 5 second rule if they had heard about it. To that effect, 70% of women were aware of the rule, and 56% of men were. 

How Quickly Does Bacteria Get on Food?

A 2006 study tried to figure out how quickly bacteria could contaminate food via salmonella. 

Surprise, surprise, the longer food was on the ground, the more bacteria made the jump from floor to food. No, they did not decide to wait 5 seconds either. Donald Schaffner, who in large part authored this research out of Rutgers University,  would come out and say bacteria could contaminate food instantly. 

Funnily enough, the Mythbusters (remember them?) found that the most meaningful difference in bacterial contamination came with the environment. Things like what the floor is made of, how humid it is, and the like. Which makes sense, turns out some nasty bugs (like stomach ones) can survive on surfaces for upwards a few months.

Proponents of the 5 Second Rule

Aston University, based in the UK, came out in 2014 and 2017 with studies on the 5 second rule (we guess they’re really invested in it). Their surveys pulled out a larger proportion of the population that followed the 5 second rule. Something like 87% of people either would or have done it before. There’s probably something to be said about the “have done it before” part. We’ve done a lot of things before that we would certainly not like to do again. 

In 2014, this was their justification it seems. Simply because a lot of people have eaten food off of the floor before, you can safely eat stuff off of the floor. 

Which is probably why they tried again in 2017, apparently concluding that some food was more okay to eat off of the floor than others? Moist foods tended to get contaminated faster, in contrast to things like gummy candy. Also carpet was worse at transferring bacteria than say, tiles. 

Genghis Khan

No seriously. The 5 second rule actually might have its origins with Genghis Khan! At his banquets, it was rumored to be called the “Khan Rule,” wherein food could stay on the floor for as long as Genghis Khan thought was okay before it was unsafe.

Of course, there was no real theory of microbiological hygiene back then, but that’s the earliest recorded instance we could find of “this is the okay time to eat food off of the floor.” Genghis Khan probably just based his rule on “is there dirt in your bread.”

At the end of the day, bacteria is everywhere, and if you’ve eaten food off of the floor and are reading this now, you’ve obviously survived and are relatively fine. Heck, bacteria on and in your body outnumbers the human cells attributed to you by about 10 to 1. 

But, that being said, it’s probably not the best idea to eat food off of the floor, intuitively. If you’re going to be doing so, the 5 second rule doesn’t really mean all that much anyway. 

Also, wash your hands. 

Bacteria are wild, see how many you can name here.

About the Author:

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Kyler is a content writer at Sporcle living in Seattle, and is currently studying at the University of Washington School of Law. He's been writing for Sporcle since 2019; sometimes the blog is an excellent platform to answer random personal questions he has about the world. Most of his free time is spent drinking black coffee like water.