5-Second Rule: The Science Behind Eating Something After It Touches The Floor

If you’re a human who consumes food, you are often faced with an existential question every time you accidentally let one slip: If a noodle falls on the floor and no one is around to watch you eat it, did it really happen?

We’re all guilty of it. Well, maybe not all (according to Vsauce video host Michael Stevens, 70 percent of women and 50 percent of men employ the 5 second rule excuse), but most of us will, at the very least, consider eating food that has fallen on the floor if immediate action is taken.

But, in the time it takes to contemplate picking it up and putting it in your mouth, it might already be too late. Does the five-second rule really exist?

Here’s when it’s not okay to eat off the floor:

When it’s been chilling there

According to Aston University researcher Anthony Hilton, food that has been picked up just a few seconds after falling on the floor is less likely to contain bacteria than when it is left there for longer.

After comparing food that had been down for 3 to 30 seconds, researchers found up to 10 times more bacteria on food that had been down longer.

Interestingly, though, scientists also assert that bacteria adhere to dropped food almost immediately, so you better act fast or it’ll spread quicker than a Yoncé-Jay Z divorce rumor.

Just how gross can it get? In a study published by the Journal of Applied Microbiology, researchers found food that touches the floor for 5 minutes can accumulate anywhere from 150 to 8,000 types of bacteria. Not the kind of seasoning you were hoping for.

When your food is moist

Like dry humping effectiveness, it’s all about making contact on the surface.

Hilton’s team also found that your food’s composition could play a factor in bacteria growth. For dry foods, like cookies and chips, the particles don’t completely settle onto surfaces, so there’s not much difference in bacteria between 3 seconds and 30 seconds.

Moist foods (candy, pasta, gummy bears), however, can make almost 20 percent more surface contact and, therefore, accumulate more bacteria in less time.

From diapers to what falls on the floor, stick to this rule: If it’s dry, let it fly; if it’s wet, not your best bet.

When it’s fallen on hardwood floors

When you fall on hard times, you’re supposed to pick yourself back up. Unfortunately, that’s not the case when it comes to your food.

Hilton’s results also showed bacteria survive for longer periods of time on hard flooring (laminated tiles, linoleum) than on carpet. Moreover, hardwood floors transfer more germs to your food than fabric surfaces (beware of those fuzzies).

Sometimes, a full carpet down there really is better.

When your food contains less salt or sugar

You think you’re making good choices in life by cooking healthy (i.e. no salt, nothing too sweet), and suddenly, you’re slapped with this fun fact: If you drop foods with low salt or low sugar contents, that item is more likely to be infected with bacteria when it’s on the floor.

All that effort for nothing.

Scientists at Manchester Metropolitan University tested cooked pasta, a biscuit (British, indeed), ham, bread with jam and dried fruit that had fallen on the floor for varying lengths of time.

According to Daily Mail, the study discovered the ham (most salty) and the bread with jam (most sugary) exhibited little signs of bacteria when picked off the floor within three seconds.

When the dried fruit and cooked pasta were examined, however, they displayed signs of klebsiella in 5 seconds and 3 seconds, respectively.

According to Daily Mail, this certain bacteria can potentially cause pneumonia, urinary tract infections, septicaemia and soft tissue conditions.

Bottom line: It’s pasta; there’s a ton of it. You don’t need the carbs, anyway.

When people have just walked on it

You think because you vacuumed one time during that last snowstorm, your floors are sparkling. You couldn’t be more wrong, but it’s not your fault. You can’t see the bacteria swarming those boards.

A study by Dr. Charles Gerba at the University of Arizona found that about 90 percent of participants' shoes had fecal matter on them (to be fair, there were only 10 participants).

Think about that the next time you’re wearing your favorite flats, and you go to eat that noodle off the ground.

When it fell on your laptop

British researchers recently discovered that your keyboard is filthier than the toilet seat (you’re welcome). One more reason not to eat lunch at your desk.