Study Debunks the Five-Second "Rule" A recent study by Clemson University questions the scientific validity of the "Five-Second Rule." The frequently cited rule claims that as long as dropped food is picked up off the floor within five seconds, it is OK to eat. Guests and callers discuss the many caveats to this less-than-foolproof approach to food safety.
NPR logo

Study Debunks the Five-Second "Rule"

  • Download
  • <iframe src="" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript
Study Debunks the Five-Second "Rule"

Study Debunks the Five-Second "Rule"

  • Download
  • <iframe src="" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript


And now, science versus temptation. We've all done it. You're about to dig into that favorite snack - a bagel with a schmear, a chocolate-covered pretzel -when it falls on the floor. Do you throw it away? Of course not, there's the five-second rule. It's a habit that often starts in grade school, but plenty of adults live by it, too.

A recent study by Clemson University raised questions about just how safe it is to eat off the floor even if it is after just five seconds.

Hearing that, would you ever abandon your belief in the five-second rule? And, well, what's the strangest thing you've picked back up? Give us a call, 800-989-8255, 800-989-TALK. E-mail us, And you can join us with your stories on our blog at

Monica Hesse is joining us here on Studio 3A. She's a Washington Post staff writer, and wrote a recent article, "That Dropped Doughnut: How Soon and How Often Will it Come Back Up?" Thanks very much for coming in.

Ms. MONICA HESSE (Staff Writer, Washington Post; Author, "That Dropped Doughnut: How Soon, And How Often Will it Come Back Up?"): Oh, thanks for having me. I feel very passionately about this rule.

CONAN: And so you believe in it?

Ms. HESSE: I believe that it's one of the greatest rules of our time. I believe that it's the only thing that allows us to get things that we really want, but maybe know that we shouldn't have.

CONAN: And shouldn't have. You say, though, it's not a question of actual bacteria. We all know or sort of intellectually understand what the Clemson study found that the germs are going to get on it even if it's only one or two seconds. Nevertheless, you say it's not about bacteria. This is a - it's a rule about ridicule.

Ms. HESSE: Exactly. Exactly. The five-second rule isn't really about us thinking that we're able to avoid getting germs on our food. What it really is, I think, is the secret societal contracts that we have that makes it acceptable for us to pick up something in public and get other people's approval for eating it. It's also our way of extending approval to other people, to say, hey man, it's okay, I'd eat that doughnut, too. Just take a bite.

CONAN: Yeah, just take a bite. And this extends - you talked to some, I guess, anthropologists, who say, you know, that this really - we use each other's reactions to guide our ingestion habit. If everybody around you goes, eww, then maybe you should put that doughnut away.

Ms. HESSE: Exactly. We've been eating together in groups for centuries, even millennia, and we've really learned that other people can be valuable tools in assessing how reasonable it is to eat something. So if someone gives a bad face or if someone gets sick from eating something, you know that you probably shouldn't touch it either.

CONAN: Yet there seems to be some flexibility in the five-second rule, both in terms of what falls on the floor, I mean, if it's a piece of broccoli, half-a-second may be too long. On the other hand, if it's a Pop-Tart…

Ms. HESSE: Absolutely. As I talked to several sixth graders, they will tell you that a Pop-Tart never gets germy, even if it's on the ground for a minute, Pop-Tarts and Chips Ahoy, they are always good. It's the minute rules for those foods.

CONAN: And another key factor is whether - whatever it is that falls on the floor stays within your sight.

Ms. HESSE: Yes. That seemed to be very important for someone. I talked to a woman who said that if she dropped something on her kitchen floor, as long as it stayed in her line of vision, it could be good for up to two hours later. But the second that she walked out of the room, she wouldn't eat it if she came back in.

CONAN: Well, what's the stigma - what's the difference if it falls out of your line of sight for a minute or two?

Ms. HESSE: Her reasoning is that as long as it's within her life of sight, she can monitor the activity happening on that cookie, but if she left, who knows, an ant could walk across, something could happen that she wasn't able to control.

CONAN: You've come to the conclusion in your story that if it's out of our line of sight, even for a second, well, then, it's eating off the floor, and that's no different between us and dogs.

Ms. HESSE: Absolutely. There - I talked to one scientist who said that, you know, we have this need to eat things in a shorter period of time, because if we don't eat them quickly enough, we'll just simply forget that we dropped them to begin with. We'll just be eating off of the floor.

CONAN: And then it's garbage.

Ms. HESSE: And then it's - then we're just like the dogs.

CONAN: Yeah. Let's get some listeners in on this conversation, 800-989-8255, 800-989-TALK. E-mail,

Our guest is Monica Hesse of the Washington Post.

And let's talk now with Janice(ph). Janice calling us from Lakewood, New York.

JANICE (Caller): Hi, Neal.


JANICE: Great show.

CONAN: Thank you.

JANICE: I just want to say I think the five-second rule is ridiculous. I always have because as soon as it touches the floor it's in the germs, they're in contact. And I always compared it to when I worked in the print shop in a dark room, you would have the red light on so people wouldn't come in and expose your materials. And inevitably, co-workers thought that they could come in quick, and they'd come in really quick and shut the door. They thought they were beating the speed of light.

(Soundbite of laughter)

JANICE: And I think it's kind of the same thing. And I just wanted to add, right before you made your comment about the Pop-Tart, I was eating a cherry Pop-Tart and I used it as an example to tell my son what the five-second theory was. He's, so, I think…

CONAN: It's a - go ahead.

JANICE: Thank you for taking my call.

CONAN: All right. Well, thanks very much. And happy eating.

JANICE: Thank you.

CONAN: All right. Bye-bye.


CONAN: It's a - it's not merely the - this idea that it might get spoiled somehow, but that it's forbidden fruit. There's the taboo, which makes it, of course, even more desirable.

Ms. HESSE: Absolutely. I mean, haven't we all tried to lose five pounds or go on a diet, and the second that you make that vow is the second that you really start wanting the things that you can't have? And I think it's the same way. If something's on the floor and it was your last M&M, you're going for it. You're getting that M&M.

CONAN: Here's an e-mail from Mary(ph) in Kent, Ohio. Why do I use the five-second rule? I'm the youngest of two children. My brother is 10 years older and much larger than me. If I didn't use the five-second rule when I was a kid, I would never have gotten dessert as he had a tendency to knock it off the table and say, are you going to eat that?

There's a variant of this which parents use, and it's the first, second and third-child rule. If you drop a cookie on the floor with your first kid, you throw it away and you give them a new one. The second kid, you pick it up and you dust it off and you hand it to the kid. The third kid, you just kick it over to them.

Ms. HESSE: Well, I was a first child, but I think that my parents were probably practicing the fifth-child rule on that. I don't think there's anything that was forbidden to eat in our house.

CONAN: Let's get Jennifer(ph) on the line. Jennifer calling from San Francisco.

JENNIFER (Caller): Hello there.


JENNIFER: My comment is more - I think it, psychologically, has to do more with wet-versus-dry than it does with time. So if I dropped a cracker or an M&M or something that's dry on the floor, it could certainly stay down there for a couple of minutes. But if it's wet and it's, you know, sticky, then it's gone, and there's no amount of time that would be safe. So, I think that's - it has much more to do with it than the time factor.

And I wonder if that's connected to the sink rule, which is, something could be on a plate and I would reach across and take a bite off my friend's plate without any problem. But as soon as that touches the sink, somehow, it's gross and it's not touchable anymore.

CONAN: It goes on the garbage.

JENNIFER: Right, exactly.

CONAN: Yeah.

Ms. HESSE: You know, she's absolutely right, though, that humans do have this intrinsic ability to, sort of, determine in secret what's germy and what's not. They've done studies that people are more willing to eat cookies off the floor than they are willing to eat cake. Cake tends to hold more moisture and so it's easier for the cake to get germs even though, as we all know, cake is more delicious than cookies.

CONAN: It's also a question of - let me ask you, Jennifer. If you have that hypothetical piece of buttered toast, and by some happy accident, had landed dry side down, would that be…



JENNIFER: I would absolutely go for it. But butter side down, it has - you have to start over.

CONAN: There you go. These are very - these are important distinctions of the five-second rule, Jennifer. Thanks very much.

JENNIFER: Sure thing. Thank you.

CONAN: Bye-bye. Let's talk with - this is Jim(ph). And Jim's with us from Shelby, North Carolina. Jim?

JIM (Caller): Yes.

CONAN: Hi. You're on the air.

JIM: (Audio gap) caught me with my pants down. I was rushing to leave the house and making a pastrami sandwich, which is one of my favorites, and I dropped a piece of pastrami on the kitchen floor. And the dog made it to it at the same time I did. And the pastrami tore in half. So the dog ate half and I ate half.

CONAN: Well, presumably, not - did your half ever touch the dog's mouth?

JIM: It kind of tore in half.

CONAN: But outside of the lip, I mean…

JIM: Yeah. Yeah. It was outside of his mouth. But he had a grab on it and I had the other end. And it tore in half. So he got half and I got half.

CONAN: That's interesting. And was it still delicious?

JIM: It was still delicious. It's my floor. I mop it. So…

CONAN: Jim, thanks very much. And we hope you feel the same way in 15 minutes.

JIM: I'm sure I'll be fine.

CONAN: All right. Thanks very much.

JIM: Okay. Thank you.

CONAN: And that seems to be another experiential rule, Monica, that, you know, people say, I have, you know, I've had this - I mean, I've never got sick before.

Ms. HESSE: Absolutely. I talked to one man who described eating a box of Raisinets that he accidentally dropped one on the floor. He found that Raisinet two weeks later and ate it because he figured that because it was in his house, he'd been able to - he knew what went on on that floor.

CONAN: And there was another of your interview subjects who said, dusty M&Ms fished out of a jacket pocket after who knows how long, perfectly okay.

Ms. HESSE: Absolutely. I believe her exact words were: It's like finding a forgotten $20 bill in your pocket, if you've ever had that experience.

CONAN: And her profession was?

Ms. HESSE: Public health generalist, she said to much humiliation.

CONAN: Here's an a-mail from Stewart(ph) in Minneapolis. Is there a George Castanza - of course, the "Seinfeld" character - rule for grabbing something, say, an eclair from the top of the stuff in the trashcan?

Ms. HESSE: You know, I think that the jury is out on that one. There seems to be a stigma where once it lands in the garbage can, we somehow think that it's worse than off the floor, even if it's on top of that doily, as George Castanza swears that his eclair was.

CONAN: Let's go to Rick(ph). And Rick is with us from Pullman, Washington.

RICK (Caller) Hi, there. Yeah. We have both kids and dogs and so we have this problem often. If it's peanut butter toast and it falls upside down, then it's certainly picked up some dog hair, which you can't see. Buttered toast upside down maybe didn't pick up any hair, and so it's, maybe, it's going to be okay. But I think the deal is that if it's within a few seconds then you saw the entire accident transpire, and so you can - you know what happened and you can pick it up and eat it. But, if, of course, it's - it sat there for a while, who knows what happened in the interim?

CONAN: So the line of sight rule aspect is - the line of sight corollary, shall we say, that's important to you, Rick?

RICK: Yeah. Oh, I think it's very important to my kids. They're three and seven, and that counts. Also, M&Ms are a whole different animal because they have an armor coating.

Ms. HESSE: M&Ms and Skittles…

RICK: Right.

Ms. HESSE: …I think, are pretty much, you know…

CONAN: Impervious, yeah.

Ms. HESSE: …stay good all the time. Impervious.

CONAN: Yeah. Yeah. Rick, thanks very much for the call.

RICK: Thank you.

CONAN: We're talking with Monica Hesse of the Washington Post about her article, "That Dropped Doughnut: How Soon and How Often Will it Come back Up?" And you're listening to TALK OF THE NATION from NPR News.

CONAN: E-mail from Sherry(ph) in San Francisco. I overfilled a glass of really expensive champagne and about a half a glass spilled on the counter. Did I slurp it up? Heck, yeah.

Ms. HESSE: That's not even the dropped food rule. That's the spilled liquid rule. Sherry(ph) might take that cake on that one.

CONAN: Yeah. But…

Ms. HESSE: The dropped cake.

CONAN: There was a corollary in your article, though, about the more expensive the item, maybe the longer you're willing to stretch that five seconds.

Ms. HESSE: That's absolutely true. I mean, if you're dropping a truffle on the floor, I'm guessing that you're going to for it faster than you go for a pork rind.

CONAN: Here's another e-mail. This from Sue(ph) in Red Wing, Minnesota. Everyone knows that jellybeans have no disposal deadline. And if you find one under the couch while vacuuming, you're entitled to eat it.

Ms. HESSE: I would agree with that. And I would add Tic-Tacs and again, Skittles and M&Ms, if we've already - as we've already ascertained.

CONAN: Mm-hmm. Let's take Saul(ph). Saul is with us from Stevens Point in Wisconsin.

SAUL (Caller): Yes. I'm a fervent advocate of the five-plus-second rule on scientific grounds.

CONAN: Really?

SAUL: Yes. And that is that it gives the chance for microorganisms, and let's not forget viruses, can mutate to a less pathogenic form.

(Soundbite of laughter)

CONAN: So you want to let evolution have its say in this?

SAUL: Yeah. We're living in an age of super bugs. And with the rates of mutations that we're talking about it's equally probable that they're going toward a less pathogenic form and I think hunger is a factor that pushes it more in the less pathogenic direction.

CONAN: Yeah. Hunger is definitely a factor, Monica.

SAUL: Yes.

Ms. HESSE: I agree. And that's - the part of what was always been taught is not to waste food, starving children around the world. So if we're hungry and we know other people are hungry, we're going to go for that.

CONAN: Hmm. Thanks very much for the call, Saul(ph).

SAUL: You're very welcome.

CONAN: So long. And let's see if we can go to - this is Brenda(ph). Brenda from St. Louis.

BRENDA (Caller): Hi, Neal.


BRENDA: Just last Thursday, my husband and my mother-in-law and sister-in-law we were at a buffet, and he loves seafood, really. And we were eating crab legs when one of them flipped under the floor. And he reached them quoting the five-second rule. And his mother looked at him in horror and said, what are you doing? And he said, you know, five-second rule. So he ate it anyway. And this is off the buffet floor.

Then, when I was a little kid, I didn't know anything about the five-second rule. If we dropped something on the ground, you just pick it up, brush off all the dirt, and kiss it up to God, and then ate it.

CONAN: Yeah.

BRENDA: You figured God blessed it, and that was about it on the rule that you have to eat a peck of dirt before you die.

CONAN: I was going to say it, Brenda, you and I and I maybe a little older than Monica. Did you grow up with that stipulation that before you die you're going to eat a peck of dirt, whatever a peck is?

Ms. HESSE: You know, I don't think that I did. But I think that it's something that kids still talk about now. When I first approached all of these children about the article, the first thing they said is, God made dirt and dirt don't hurt. And that's how they knew it was okay to eat.

CONAN: Brenda, thanks very much, and good eating.

BRENDA: Thanks. (Unintelligible).

CONAN: Bye-bye. And finally, the last person you talked to in your article, or the last person you quoted in your article, may have pushed the limits of this further than - all right, Skittles are impervious, M&Ms, Mike and Ikes, he found on the floor of the movie theater where he worked.

Ms. HESSE: He did. Mike and Ikes are gelatinous and they're not Skittles and they're not M&Ms, but he figured that he was hungry. They looked pretty good. And hey, as he said, he'd never got sick.

CONAN: Monica Hesse, a Washington Post staff writer, author of the recent article, "That Dropped Doughnut: How Soon and How Often will it Come Back Up?" with us here in Studio 3A. Thanks so much for your time today.

Ms. HESSE: Thank you.

CONAN: Before we go, just to remind you that tomorrow we kick off our summer movie series. Murray Horwitz will be back. Every Thursday, we'll pick a film category. You send us your votes for best movie in that category and a brief reason as to why. We'll award one of them with The Murray. Things get started tomorrow with the best of the big-caper movies.

(Soundbite of movie "Ocean's Eleven")

Mr. BRAD PITT (Actor): (As Rusty Ryan): Why do this?

Mr. GEORGE CLOONEY (Actor): (As Danny Ocean): Why not do it? Because yesterday, I walked out the joint after losing four years of my life, because the house always wins. Play long enough. You never change the stakes. The house takes you. Unless, when that perfect hand comes along, you bet big, and then you take the house.

Mr. PITT: (As Rusty Ryan) You've been practicing this speech, haven't you?

Mr. CLOONEY: (As Danny Ocean) A little bit. Did I rush it? It felt like I was…

Mr. PITT: No. It was good. I like it.

CONAN: George Clooney and Brad Pitt in a scene from "Ocean's Eleven," one of the more recent caper films. There are plenty of others - "The Sting," "Snatch." We'll let Murray weigh in with his favorites, top Cappie maybe. Send us your pick of the best big caper movie. The address is again is,, and we'll see you back here tomorrow.

In Washington, I'm Neal Conan, NPR News.

Copyright © 2007 NPR. All rights reserved. Visit our website terms of use and permissions pages at for further information.

NPR transcripts are created on a rush deadline by Verb8tm, Inc., an NPR contractor, and produced using a proprietary transcription process developed with NPR. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.