Smarter: Does the 5-Second Rule Work?

By Pang-Chieh Ho

This week I’m offering some food for thought, specifically food that has been on the floor for less than 5 seconds and whether it’s safe to eat it. Also in this issue: Would you know if your catalytic converter was stolen, and the best apps for finding where shows are streaming.

THE BIG STORY:

‘You Are What You Eat (Hopefully Not)’

Let’s get this out of the way: I have dropped many a food on the floor in my day, and of the things I have dropped, I have eaten quite a few.

It seems like I am not alone when it comes to partaking of food that was once on the floor. Eighty-four percent of participants of our Instagram poll said they’ve done the same thing, with most saying they limit it to food that’s fallen on the floors inside their home.

I personally cannot fathom eating anything off the floor of a public space. For instance, would I ever eat a slice of pizza I had dropped on the streets of New York City, streets that, one time or another, have been graced by the presence of dog feces, pigeon droppings, and trash cascading out of bins? No, because I have standards. They’re not high, but they’re there.

To me, a Cheeto that has fallen onto my living room floor is more fair game, as is a blueberry I’ve just dropped in the kitchen. Both are surfaces that I consider to be fairly clean. And in case anyone around me is questioning whether that’s sanitary, I sometimes evoke the 5-second rule, though I’ve never really probed deeper into whether the rule is actually a scientifically proven one.

So is the 5-second rule legitimate or am I putting myself at risk? Here’s what experts say.

The 5-second rule isn’t really valid.
You shouldn’t be eating food that’s been on the floor, even if it’s for less than 5 seconds, says James E. Rogers, PhD, the director of food safety research and testing at Consumer Reports, who says he would never eat anything off the floor nor would he let his children.

A 2016 study from Rutgers University found that the transfer of bacteria from a contaminated surface to a piece of food can happen almost instantaneously in some cases, thus disproving the 5-second rule.

The study also found that with some foods, the longer they sit on the surface, the more bacteria is transferred, says Donald W. Schaffner, PhD, one of the study’s authors, an extension specialist in food science, and a distinguished professor at Rutgers University in New Jersey.

There are, however, other factors that affect how much bacteria your food is going to pick up. For instance, bacteria transfers from a floor to wet food at a more rapid pace than dry food, so the risk from a piece of watermelon is quite different from a piece of toast or candy, Schaffner says.

The type of contaminated surface also matters. According to Schaffner’s study, as well as a 2006 study published in the Journal of Applied Microbiology, carpets transfer bacteria to foods at a lower rate compared with surfaces such as ceramic tiles.

What’s the risk of eating something off the floor?
First of all, you can’t tell how much contamination is really on the floor, James says. So even if your kitchen floor might appear very clean, its bacterial or viral hazards are invisible to the naked eye.

And if you wear your shoes indoors, you’ve probably walked on sidewalks and other public places so you’re transferring germs from the bottom of your shoes to places such as your kitchen floor, says Brian Sheldon, PhD, a food safety specialist and co-author of “Did Just You Eat That?” It’s a book that explores common food myths, including the 5-second rule. (Probably another reason CR really encourages people to not wear their shoes indoors.)

So if your shoes transfer germs from outside to your floor, or germs get there some other way, you could end up eating harmful bacteria and get sick. The risk is greater for more vulnerable populations, such as younger children, older adults, and people who are immunocompromised, says Sana Mujahid, a scientist who manages food safety research and testing at CR, including testing for pathogens in meats and produce.

It’s worth noting that the probability of you getting sick from dropped food is not super-high. But in the off chance that you do drop food on a spot where there’s bacteria that will cause you severe illness, that bacteria is definitely going to go on your food, says Paul Dawson, PhD, a food scientist and Sheldon’s co-author of “Did You Just Eat That?”

Are there any cases when you can pick something off the floor and it’ll be fine? 
If it’s a food that you can wash off, such as apples, plums, and blueberries, or food you can peel, such as potatoes and onions, you should be okay, James says. Otherwise, it’s probably best not to risk it.

And if it’s food that will be cooked after falling on the floor, the risk is less compared with ready-to-eat foods that aren’t heated or cooked after you pick them off the floor, Sheldon says.

Ultimately, it’s good to exercise your common sense. Before you pick up something from the floor to eat, think about what type of floor it is, what might have been on it, and who’s going to be eating the food, Sana says.

THOSE NUMBERS DON'T LOOK GOOD

The only time I’ve tried using auto-captions is when I’m watching YouTube videos that I’m having a hard time understanding, and I can tell you that every time I’ve regretted my decision.

Usually, I end up switching the auto-captions off within seconds because of the high, almost comical, number of mistakes. And according to a CR investigation, terrible auto-captions aren’t unique to YouTube. In fact, the error rates of YouTube’s transcription software are actually fewer compared with platforms like Zoom, Facebook, and Google Meet, according to CR-funded research that tested their accuracy using TED Talk videos.

Why this is a problem: Some programs make more than one mistake per 10 words, and the results are usually worse when English isn’t the speaker’s first language—even if they’re fluent. All these mistakes can add up and have a huge impact on comprehension for people accessing these videos who don’t speak English as a native language. It’s also hugely problematic for people who are deaf or hard of hearing.

ASK AN EXPERT

Illustration: Sam Island

Question: 
Catalytic converters being stolen is a huge problem where I live. If someone stole one from my car, would I be able to tell?

Answer:
You would notice for sure, says Jake Fisher, who oversees auto testing at CR. Cutting out a catalytic converter removes a key part of your exhaust system. Though your car will probably still start, it will be incredibly loud (try to imagine race-car-level loud). And if you attempt to drive it, you’ll likely be dragging the rest of your car’s exhaust system on the ground.

If you want to prevent your catalytic converter from being stolen, here’s what you can try.

THE GOOD STUFF

These are five things that our dishwasher expert Rich Handel would never do.

Any questions about dishwashers? Ask us anything.

EMERGENCY MEETING

What can you do in the face of a weather emergency, such as a hurricane?

🏠 Get your home ready for evacuation.
If you’re protecting your home against hurricanes and floods, shut off your power and water, secure the windows and doors, and take pictures or a video of everything you own in case you need an inventory of your belongings for insurance purposes.

🎒 Have a “go bag” ready.
Pack a bag filled with essential items such as water, nonperishable food, a first-aid kit, prescription medication, and other supplies you might need in a disaster. (Read the complete list of things to pack here.)

⚡Prepare your electronic devices.
Make sure all your devices are fully charged and bring spare batteries and portable chargers. Also bring a car charger, which is a handy way to charge your phone if you lose power.

Read more tips about how to prepare for a weather emergency, including what to do if you encounter a flood driving on the road.

MUST-READS OF THE WEEK

🏈 How to Stream NFL Games Without Cable
Streaming services like Amazon Prime and YouTube TV will allow you to watch games.

💰Where Consumers With Little or No Credit Can Get a Loan
Here are some nontraditional loan alternatives that you can consider.

⛔ How to Keep Ticks Away Without Using Pesticide
Just because summer is ending doesn’t mean that ticks are going away soon.

🛣️️ 10 Most Satisfying Cars by Region (Available to CR members)
In one of the regions, the Tesla Model 3 ranks as No.1.

More from Consumer Reports:
Top pick tires for 2016
Best used cars for $25,000 and less
7 best mattresses for couples

Consumer Reports is an independent, nonprofit organization that works side by side with consumers to create a fairer, safer, and healthier world. CR does not endorse products or services, and does not accept advertising. Copyright © 2022, Consumer Reports, Inc.