Trivia: The Five Seconds Rule

Posted by Alex in Daily Trivia, Food & Drinks, Science & Tech on May 23, 2008 at 1:38 pm


Scientists have actually investigated the Five-Second Rule.

The Five-Second Rule states that it’s okay to eat a dropped piece of food, as long as you pick it up before you can count to five.

In 2003, a high school intern at the University of Illinois named Jillian Clarke conducted a survey and found that half the men and 70% of the women knew about the five-second rule. Jillian then conducted this experiment: first, she contaminated a ceramic tile with E. coli bacteria, then she
placed gummy bears and cookies for 5 seconds and analyzed the food: they sure were contaminated.

In 2007, professor Paul L. Dawson of Clemson University and colleagues repeated the experiment. This time, the test surfaces were tile, wood flooring, and nylon carpet; the food were bread and bologna; and the bugs were salmonella. They discovered that a) salmonella can survive for 28 days on a surface and b) in just 5 seconds, anywhere from 150 to 8,000 bacteria transferred to the food.

So what does this mean for the Five-Second Rule? Do what you like, but remember: the infectious dose (the smallest number of bacteria that can actually cause illness) is as low as 10 for salmonella and 100 for E. coli. (Source)


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COMMENT

17 comments to "Trivia: The Five Seconds Rule"

  1. Tempscire
    May 23rd, 2008 at 2:19 pm

    Hmm. I thought there was another experiment that showed it depended on how moist the food was-- an apple slice would pick up more bacteria than an M&M, say.

  2. Abbey
    May 23rd, 2008 at 2:24 pm

    But what are the odds of salmonella or E. coli being on the surface you happen to drop your food on?

    There's many factors that go into my decision to follow the 5 second rule or not. How hungry am I and how much do I like the food that I just dropped? What sort of surface did I drop it on and is it the last one? It's a lot to think about in just 5 seconds.

  3. v.dog
    May 23rd, 2008 at 3:28 pm

    They could have just watched Mythbusters

  4. bean
    May 23rd, 2008 at 3:42 pm

    The problem with these studies, including Mythbusters, is that they don't stay true to the scenario:

    The five second rule is for food that has dropped from a height, not been placed carefully on top of a bacteria smear.

  5. edselpdx
    May 23rd, 2008 at 3:46 pm

    I would eat something after 5 seconds on my kitchen floor... but not a public bathroom floor...
    Context is everything here. Even ingesting E. coli is not *necessarily* going to make you sick. And most environmental bacteria will not make you sick. Food is not sterile.

  6. Thomas
    May 23rd, 2008 at 4:11 pm

    I follow the three second rule

  7. CheeseDuck
    May 23rd, 2008 at 4:26 pm

    I personally follow the As Long As It Isn't Rotting Rule.

  8. kurt
    May 23rd, 2008 at 7:26 pm

    As much as I respect High School science projects as proof of something, the method is flawed. actual floors do not have bacteria smeared on them (though any food residew left on the floor would be a fine place for bacteria to grow in the future).

  9. Arjun
    May 23rd, 2008 at 9:14 pm

    Does anyone remember reading a number of studies somewheres which actually refuted the idea that bacteria transfer to food within a few seconds, and that it actually took really long?

  10. Barbwire
    May 23rd, 2008 at 10:26 pm

    Some MIT students did a study, dropping things randomly in ordinary places. Most foods tested were ok after 5 or 10 seconds, and some were still fine after a much longer time on the floor/ground. I agree that placing something on a surface smeared with a concentration of bacteria will not produce accurate results.

  11. Celeste
    May 24th, 2008 at 3:20 am

    Eh, you're more likely to get salmonella from bagged lettuce than from a dropped Oreo. Live a little. =P

  12. BikerRay
    May 24th, 2008 at 5:28 am

    Some of the unhealthiest people I know are the most fanatical about cleanliness; their immune system never gets any practice.

  13. violet
    May 24th, 2008 at 5:53 am

    Yeah, it's not so much that people follow the 5 second rule because they believe bacteria can't get into the food in under 5 seconds; it's just an arbitrary length of time that we feel psychologically comfortable with. The difference between "I dropped it" and "I'm foraging for scraps on the floor."

  14. Ashley
    May 24th, 2008 at 12:52 pm

    Another study found that people are very willing to follow the five second rule for candy, and quite unwilling for vegetables. It's definitely psychological.

    That said, it is actually good for your immune system to be challenged occasionally. They way when you DO eat contaminated lettuce, your immune system says "Big whoop, I've seen this before. No problem." The chance of getting a major, knock-you-flat bacteria or virus from a surface you are familiar with (ie: not a public bathroom or cafeteria) is low.

  15. Larry
    May 24th, 2008 at 4:24 pm

    I heard that even ancient Romans had a version of the 5 second rule, except it was the 40 second rule back then. My how times have changed.

  16. Sofar
    May 24th, 2008 at 6:24 pm

    I'm going to go ahead and assume my floor is home to a minimum of salmenella and continue to eat stuff off of it no matter how long it's been there. Unless it gets hair on it.

  17. jax
    November 23rd, 2008 at 2:25 pm

    my science fair project is about this and its more accurate.
    its simple;
    dont smear bacteria over the surface,
    do it over somewhere that people might actually pick up off the floor and eat it.

    btw,
    "Tempscire" is right.


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