‘Five Second Rule’ for Food on Floor Is Untrue, Study Finds | Hacker News Reader

‘Five Second Rule’ for Food on Floor Is Untrue, Study Finds

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39 pointssethbannon86 comments

I'm pretty sure the "5 second rule" is just something people (like myself) use to justify doing something gross, such as eating something that was dropped; and at least in my case, I never believed for a minute that it was "sanitary" if it spent less than 5 seconds on the floor.

It's more a mental thing ... if it's only been there for 5 seconds, it's cool. If it is longer than 5 seconds, well, then you're eating food that's been sitting on the floor. Now that I'm typing it, it makes even less sense -- but that doesn't mean I'm going to stop doing it. I've made it 30+ years without side-effect ... ha

If you really wanted to test the five second rule, you'd have to be broader. Who is overall better off?

1. The person who NEVER eats food off the floor 2. The person will ALWAYS eats food off the floor 3. The person who follows the 5-second rule

I wouldn't be surprised if the 5 second rule gives its followers a net benefit. You're slightly more likely to get sick, but you waste less food and live a less paranoid life.

I'm sticking with it, but not for watermelon.

Exposure to bugs also builds up resistance. I wonder if eating food off the ground leaves you with a stronger immune system?

The thing that really a noticeable difference in my immune system was working in a bar. You come into contact with so many people, many of whom don't take good care of themselves, and end up collecting / washing the glasses they have been drinking out of, shaking their hands, handling their IDs, wrestling them out of the building. I was sick constantly for like six months, but after that, I almost never got sick again.

Sadly, it appears to be wearing off. I was sick for a fair bit last winter, and it'll probably be the same again this year.

Purely anecdotal, but I eat lots of unpasturized fermented food, I re-use silverware/dishes/cutting board with just a quick moist cloth wipe, and I haven't been sick in around 7 years. Occasionally I'll notice increased mucus and mild inflammation my nose/throat that tells me I've been exposed to something, but it always goes away within about 8 hours.

I noticed this as well when I started taking probiotics, eating unpasteurized cheeses, and having sauerkraut or kimchi every other day or so.

I'll get a sniffle for a day and then that'I'll be the end of it. I haven't been sick in a year.

Yeah, many of the comments talk about bacteria, evolution, our immune systems being able to deal with bacteria, and that is all fine and good.

But what about chemicals and cleaning supplies? Eg the floors in a restaurant (and tables, too) get cleaned with some strong chemical products. That's definitely not food grade and no amount of evolving is going to help you deal with that. I see people put their forks, etc, on directly on table surfaces that were previously wiped with a cleaning cloth and I think that's careless. The floor would be even worse.

Eating from your dog is fine and probably has health benefits. Eating from a (chemically cleaned) floor is still not.

The dose makes the poison. The amount of lysol residue or whatever that gets on your dropped skittle is tiny. You probably eat it all the time, whenever you touch the table and then your food.

Anyway in general danger of exposure to chemicals is seriously overblown. I love this E.T. Jaynes quote:

>...for virtually every organic substance (such as saccharin or cyclamates), the existence of a finite metabolic rate means that there must exist a finite threshold dose rate, below which the substance is decomposed, eliminated, or chemically altered so rapidly that it causes no ill effects. If this were not true, the human race could never have survived to the present time, in view of all the things we have been eating.

>Indeed, every mouthful of food you and I have ever taken contained many billions of kinds of complex molecules whose structure and physiological effects have never been determined – and many millions of which would be toxic or fatal in large doses. We cannot doubt that we are daily ingesting thousands of substances that are far more dangerous than saccharin – but in amounts that are safe, because they are far below the various thresholds of toxicity. At present, there are hardly any substances, except some common drugs, for which we actually know the threshold.

"I see people put their forks, etc, on tables"

What? If you can't put your forks on the table where can you put them?

I always put my fork on the table, that's what the tables for.

How do you lay your table?!

Forks are often wrapped or placed on a napkin you can then lean them against the plate whilst you're eating.

A posh restaurant would have a table cloth that would be cleaned daily with less harmful chemicals.

Wouldn't the napkin be touchin the table then? Or do you ask for a fresh napkin so you don't have to use the one from the table? And ask about the storage of the napkins and silverware, in comparison to any cleaning solutions or other chemicals?

Typical setting would be on top of a plate, on top of a napkin, wrapped in a napkin, etc., never directly onto a table surface.

> Yeah, many of the comments talk about bacteria, evolution, our immune systems being able to deal with bacteria, and that is all fine and good.

It also ignores parasitic worms. People go blind from eg toxocara, which is spread by dog faeces. Only about 700 people per year in the US, but it's avoidable and preventable blindness.

> . I see people put their forks, etc, on tables that were previously wiped with a cleaning cloth and I think that's careless.

The amount of cleaning chemical you're going to eat by putting a fork on a table is tiny, and if that causes harm putting bare forearms on the table is going to be risky too.

> but that doesn't mean I'm going to stop doing it. I've made it 30+ years without side-effect ... ha

If anything, it's probably been of some marginal benefit -- keeping your immune system on its toes.

Exactly! For skittles, it's more like the 5 day rule!

Of course it picks up bacteria. Bacteria are numerous and everywhere. But we've lived with them so long that we can deal with unsterile environments for the most part. Most people for most of history were not germaphobes, and didn't even know bacteria existed. If eating something off the floor had a high chance of killing you, the human race would not have survived this long.

Only bacteria that have evolved to infect humans really scare me. So in a public place I probably would not pick something off the ground. But in my own house, I know no one there had tuberculosis. In my life I've eaten tons of berries and stuff that grow outside or even on the ground, and have never had a problem.

I don't understand how someone can think this is true. Like, what, you drop your toast with jam on the floor, pick it up in a second, the jam is full of hairs/dust/debris and you figure it's fine?

No, no one thinks that way with regards to any kind of food item with stickiness and the 5 second rule.

The thought revolves around dry foods and the (mistaken) impression they're unlikely to accumulate any kind of debris and dust. Peanuts, pretzels, etc.

That's my impression too. You explain the rule to children, so they can pick up peanuts they drop on the floor, but don't go eating peanuts they find dropped by other people a long time ago.

Your logic has many bugs.

What's wrong with just explaining that they shouldn't eat stuff from the ground. Period?

Do you have children? "Explaining they shouldn't do X" and "the child don't do X" are, ah, much less correlated than you might like. At times they can be downright reverse correlated.

>What's wrong with just explaining that they shouldn't eat stuff from the ground. Period?

Wasting food for no good reason. And making them paranoid about germs.

That makes sense(especially about the germs paranoia).

The way I see it, if they're too small, you need to watch them anyway, or else they will put everything on their mouth, not just dropped food.

If they are over that, they're smart enough to understand that they don't eat jelly sandwitch off of the floor, or something they dropped in a public street. But for a casual hard food stuff they dropped on the kitchen floor or living room etc, they can sweep it and eat it -- and get some germ resistance too.

E.g.:

Just as a baby's brain needs stimulation, input, and interaction to develop normally, the young immune system is strengthened by exposure to everyday germs so that it can learn, adapt, and regulate itself, notes Thom McDade, PhD, associate professor and director of the Laboratory for Human Biology Research at Northwestern University.

Exactly which germs seem to do the trick hasn't yet been confirmed. But new research offers clues.

In a recent study, McDade's team found that children who were exposed to more animal feces and had more cases of diarrhea before age 2 had less incidence of inflammation in the body as they grew into adulthood.

Inflammation has been linked to many chronic adulthood illnesses, such as heart disease, diabetes, and Alzheimer's.

"We're moving beyond this idea that the immune system is just involved in allergies, autoimmune diseases, and asthma to think about its role in inflammation and other degenerative diseases," McDade says. "Microbial exposures early in life may be important… to keep inflammation in check in adulthood." (WebMD)

or:

http://news.ubc.ca/2016/08/10/why-your-kids-should-play-in-t...

Society. Kids that are raised outside of what is considered the acceptable social norm often have problems adjusting when they get older. For example I actively try to avoid eating out at restaurants with people who are too fussy about their food. It's usually an awkward uncomfortable scene. I'd much rather share a meal with a '5 second rule' type of person.

Ok, although I didn't get the part about "eating out at restaurants with people who are too fussy about their food".

Are there adults out there who are fussy with their food? In what way?

It's obviously not about debris/hairs/dust but germs.

In other words, if a person saw hairs/dust/debris in their jam that fell on the floor, they wouldn't eat it anyway.

But if something less sticky (and more solid) was dropped, say an apple or a pizza piece that fall on the bread side, they might pick it up, sweep it a little, and eat it.

In fact, 5-second-rule or not, most people will be fine for doing so anyway, as long as they do it on their relatively clean home -- with germs that they are usually in contact anyway.

Eh, sure, if it's a pretzel or a piece of candy or whatever, we (in my country) will pick it up, blow on it a bit, wipe it a bit and eat it. It depends on where it fell and how sticky the food is, but obviously "time spent on the floor" isn't really a factor.

>Eh, sure, if it's a pretzel or a piece of candy or whatever, we (in my country) will pick it up, blow on it a bit, wipe it a bit and eat it. It depends on where it fell and how sticky the food is, but obviously "time spent on the floor" isn't really a factor.

It might might not be a conscious following of the 5-second-rule, but I'm sure the people in your country would still pick it up fast and not let it collect germs kana eikosalepto before eating it.

Eikosalepto is a lot, but eh, you just wouldn't agitate it while it was down. Three, five or ten seconds don't matter that much.

My friends and I joke about it, but I didn't think anyone took it seriously.

I thought it was the 5 minute rule. Or the "if you see food on the floor, and it wasn't there yesterday, it's good" rule.

Okay food that wasn't there yesterday is pushing the limits of comfort :D

Psssshhhh Mythbusters busted that years ago:

http://www.discovery.com/tv-shows/mythbusters/videos/five-se...

Some people won't believe it unless a professor says so.

Vsauce also talked about it over 3 years ago https://youtu.be/rYXdsOEWBj0

My philosophy is that I just don't waste food. Has nothing to do with "five second" rules. If I just spent time making an amazing sandwich, and it drops on the kitchen floor mostly intact. I'm sure as shit eating it. Obviously gloppy sauces, and subway tunnels, I'm not going to scrape off the ground. For the rest, that's why we have immune systems.

It's a social convention not a piece of 'folk physics'. You know it's dirty but you don't have to explicitly say that you don't care.

I wasn't aware that anyone took the "Five Second Rule" seriously. I thought everyone knew it was a sarcastic joke.

Before we had kids, if a bite of the most delectable piece of grilled steak touched the surface of our kitchen table, I would not eat that piece of steak. In my mind, it was contaminated and a great risk to eat.

Now that we've got kids, I will eat that same piece of steak even if it falls on the floor. There's just so much good food on our floor now. Goldfish, Cheez-Its, bananas, etc.

Perhaps marginally related, our kids are the healthiest in their classes.

> "Now that we've got kids, I will eat that same piece of steak even if it falls on the floor"

... after the kids have taken a couple of bites of it and the dog sniffed at it. At least in my world. But I draw the line at the dog actually taking a bite from it.

On that note, a friend of mine (unknowingly) used water he thought was clean, but that came from a glass my cat had been drinking from, to dissolve heroin for injecting. The resulting infection nearly caused him to lose his leg - the lab analysis of the wound revealed the infection was caused by cat-saliva bacteria.

Anyway, just saying there are dangers from pets and allowing them to share your environment. Although, I let my cat take bites out of my food sometimes, and that seems OK so far.

> On that note, a friend of mine (unknowingly) used water he thought was clean, but that came from a glass my cat had been drinking from, to dissolve heroin for injecting. The resulting infection nearly caused him to lose his leg - the lab analysis of the wound revealed the infection was caused by cat-saliva bacteria.

> Anyway, just saying there are dangers from pets and allowing them to share your environment.

While that's true, the particular dangers from injecting cat saliva are usually pretty minor (not low harm, just low probability: you mostly run into them if you get bitten by a cat so that it draws blood, and you deal with them by treating that -- rare -- event as an emergency requiring immediate attention.)

The real danger revealed by the incident you describe is using poor cleanliness standards when injecting drugs (in this case, recreational, but that's irrelevant to the hazard, though its probably a lot more common with recreational drug use than otherwise). You don't use water that you merely "think" is clean for any purpose associated with injection, whether its cleaning anything used in the process or, worse, actually injecting.

> Although, I let my cat take bites out of my food sometimes, and that seems OK so far.

You probably shouldn't, though ingesting material contaminated with cat saliva its still probably much safer than injecting it.

Did he not "cook" the solution? Or did the bacteria somehow survive the process?

> In my mind, it was contaminated and a great risk to eat.

So, I'm interested in how you arrived at this thought. It certainly can't have been learned behaviour due to cause and effect - I don't think there are any recorded instances of food touching a dining table, being eaten, and the eater becoming ill afterwards, let alone that this happened to you (although, it may have, which would be interesting) so was it taught to you, or just over-cautious extrapolation?

Personally, I'm a great believer in floor food, and it hasn't ever worried me or caused health problems ;)

Next up: "Stepping on Cracks Not Injurious to Mothers' Spines."

I was under the impression that this was common knowledge? I knew it as the 3-second rule.

Varies depending on the floor type, I believe.

On speed of pet dog. In Y seconds either the dog has determined it to be edible and its gone, or its inedible and should be tossed in the trash.

Or speed of toddler. We have cascading rules in our house: anything that hits the floor is his within three seconds or else it defaults to daddy, who has the remaining two seconds before the dog makes his move.

Dinner-time incidents can turn violent quite quickly...

LOL DnD style roll for initiative, sorry, Spot, your D20 rolled a 7 and the toddler got a natural 20 so ...

I have strong anecdotal evidence that 'Five Second Rule' does not work on cat hair.

It's important to always rinse cat hair before consuming it.

I generally try to avoid consuming cat hair if I can... but at the point i'm consuming cat hair, I'm not sure rinsed is better.

But on second read, I'm guessing you meant to rinse off the cat hair?

My ancedotal evidence says it depends. A handful of candy dropped will have cat hair: A single piece, maybe not.

I generally brush it off and eat it nevertheless.

That's why you brush or rinse it off first depending on the food in question.

I think you might have forgotten the most sanitizing procedure. Blowing on it. Works for NES cartridges and cat hair on a cookie.

Well today I just dropped my cigarette to the street floor. I hesitated to pick it up but hey, it can't be worse than smoking itself.

The question is not whether or not the food picks up bacteria, but how likely the bacteria is to endanger our health (and how likely a deficiency of bacterial exposure caused by being too careful is to endanger our health).

I always thought this was only a joke. I guess we've reached peak science.

I either heard about this article or read this article a few days ago... Which got me to thinking, did people actually think the 5 second rule was a real thing?

Common knowledge is: if food falls on the floor and survives the impact you pick it up quickly, wash it, it's ok. If you find it after hours you trash it.

so while gummy bears are least likely to gather germs, how about hard candy? also, what are the differences compared to your hands? what about a communal candy jar or shared food space?

while I understand the five second rule is just some silly fun I am still not convinced that much else is better. unless your using a completely sanitary environment with sterilized equipment you will always get some bacteria

This study has been done a million times before, at the jr high and high school level and I thought everyone just kind of knew this already.

The article did not provided much useful information about food born illness. Watermelon picks up more bacteria than a gummy bear when dropped on the floor. That is obvious. A couple of things that would be much more helpful to point out: 1) your kitchen floor is much less likely to be coated with salmonella if you avoid bringing raw chicken carcasses into your house, and 2) a major factor in the severity of food born illness is dose. It is much safer, for example, to pick up a piece of watermelon from the kitchen floor ant eat it immediately than it is to pick it up and toss it in a salad that you are taking to a picnic, giving any bacteria that was picked up hours to multiply at moderate temperatures before being eaten.

Sad that someone had to do a study to find out something that people should know through common sense.

On a related note, who cares? Kids eat mud and it doesn't kill them; a bit of food that fell on the floor that might have a speck of dust on it is unlikely to kill us.

I wonder how human beings from centuries ago (and actual animals) have been able to survive without our clean like a lab environment?

Would it be possible that we overstate quite a bit the danger of everything?

I prefer my beer, cheeses non pasteurised and I prefer raw milk (after being boiled). And I think the food coming from puritans victorian inspired countries taste blend like the catholic religion.

Most unhealthy illegal (by brits laws) traditional french cooking I have eaten from Québec was tasting like real fucking good FOOD.

Hail to the artisinal food! fear not the propaganda from industrial food processors (unilever, procter&gamble, lactalis, nestlé ....)

Be curious, fear not (except if you are pregnant) and resist the messages of fear.

Pasteurization happens at 140F, if you boil Raw Milk isn't that the same thing just more crudely executed.

It would seem boiling milk defeats the purpose of raw milk.

Short answer: They didn't survive. IIRC a significant portion of all humans born in past centuries simply died as infants/children, usually from things that are trivially preventable today with basic hygiene, good nutrition and antibiotics/vaccines.

Humanity as a species obviously survived because people simply had a lot of children to compensate the high mortality rates.

well, I beg to differ, and quite a lot.

I am a mover educated with a master in physics.

My father is a physician.

a Physician - physicist talk looks like this :

Dad, medical studies are not science ; for instance fat are goods, then bad then good again.

Son, Newton laws have been proven wrong by Einstein

Dear dad, Newton laws are still valid in the right domain, something proven wrong may be proven wrong at the edge but not in its core, if medecine was science, fat would always be good most of the time, except when ...

Yes, but we medics invented meta analysis that made the science better

You are mainly comparing apple and potatoes without blinking, and you are surprised the results of your studies are hardly reproducible.

Long story short; hygienists are leading medical science based on their religious believes (like Pasteur with alcohol) and believes are hardly a good way of leading studies, and I am used to live every day with a tenant of as soft science as psychology/philosophy/history that has a diabete type II for believing in the BS of his fellow «scientific» colleagues, and I do not know if I am angry or laughing.

They need a study to figure this one out?

The two second rule still applies though.

I refuse to read the article. It can't be true someone believed that to a point a study had to be made.

Its absolutely true. I've already decided and I'm teaching my grandkids that, regardless of what Nana says.

Interestingly, I have never heard about such a rule (being from Europe; is it probably a US-thing?)

Guess I'm gonna be eating stuff that's been on the floor for longer now... ;-)

OMFG, there's a study for that....

lol, do people really believe that bugs are going "hold up! wait 5 seconds before attacking!?"

I think the idea here is that a significant enough number to get you sick, haven't had a chance to set up shop. We eat germs all day, it's when we get too much at once that there is an issue.

Also in breaking news:

Stepping on Sidewalk Cracks Does Not Break Your Mother's Back

Nor is the floor lava.

Better safe than sorry! I'm not touching that! leaps from chair to chair

Er... Please tell me tax money wasn't wasted on this study. We all joke about it, but come on, are you really telling me someone wasted money studying this? We all know germ transfer is fairly immediate. My whole family spends much of our time filthy from living on and operating a farm, and I n your average shoes off household, you're less likely to get sick eating something that just fell on the floor than you are to get sick. That's not to say you won't get sick, it's also not to say that what you catch won't be fatal, but really... we all laugh and joke and yell "5 second rule!" before knowingly taking our lives in our own hands and guess what? So far, we're still all here and so far we spend a lot less time sick than many people we know.

We know the 5 second rule is bullshit, we don't need a study to tell us that, we're not idiots. Some people are into adrenaline sports and driving wrecklessly, we play 5 second rule Russian roulette. It's good for your immune system, until it kills you.

> We know the 5 second rule is bullshit, we don't need a study to tell us that, we're not idiots.

We may not be idiots... but there are plenty of idiots out there who believe this.

Plenty enough for me to get down voted for that comment :D

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