The 5 Second Rule Gets Its Annual Debunking
    By Hank Campbell | October 17th 2012 04:52 PM | 7 comments | Print | E-mail | Track Comments
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    Every few years, San Diego State researchers and Clorox get together and produce a study showing that the 'five second rule' - how long food can be on the floor and still be safe to eat - is not really true.  Instead, germ transmission, like electricity, happens really fast. Researchers told us this in 2010, last year and they told us again today and various other times going back to 2003, when I stopped looking.  It's almost like McClatchy/Tribune News is on a contract to give this stuff coverage but they aren't the only ones.  It usually happens when it's a slow week for miracle vegetables and/or scare journalism about last week's miracle vegetables.

    Well, we always knew that the five second rule was more of a guideline than a rule. It's been around a lot longer than germ theory.  I am noodling a book about Genghis Khan and so I have been reading a lot of things about this mass-murdering sociopath. So when I saw what is apparently an annual puff piece from the mainstream media about the five second rule I was reminded about the fluid nature of its historical origins. 

    History, of course, is rather subjective.  I imagine the 5 second rule was 5 days in prehistoric times, when food was harder to come by, so pinning down when it became a 5 second rule is just guessing. Genghis Khan was a rather scientific guy for being a homicidal rapist maniac so he had his own notions on how long food could be on the ground and still be safe.  And he was right - obviously eating food off the ground was a lot safer than going to war and he was always going to war.  And organic food buyers today think food can sit in pesticides forever, as long as they are organic pesticides.

    Even an M&M tried to work the folklore in this 1999 commercial:

    Germs can attach themselves, we have known that for a while. But for this study they wanted to find out how long a 'food on the floor' rule might be.  They used some carrots (and then a control group of one carrot kept clean, though I have no idea why they think they need a control group or what they consider 'clean') and found that all the surfaces couldn't keep food clean for 5 seconds. Some were worse than others. Countertops fared more poorly than a carpet. No one saw that coming.

    Now, Clorox is in the cleaning products business so the results are obviously correct but that doesn't make them valuable.  There is a big difference between picking up a grape from a reasonable floor versus a peanut butter sandwich that lands face down in a house with pets.   If you drop a Twinkie, the long-term effects from the Twinkie are not the germs.

    Did Clorox and the San Diego researchers examine how long Clorox bleach lasts on countertops after cleaning and can be transmitted to food?  Errr, no, that would just be silly.

    More reading:

    Hewitt KM, Gerba CP, Maxwell SL, Kelley ST (2012) Office Space Bacterial Abundance and Diversity in Three Metropolitan Areas. PLoS ONE 7(5): e37849. doi:10.1371/journal.pone.0037849


    Gerhard Adam
    How does the "five second rule" hold up to the hygiene hypothesis?
    Mundus vult decipi
    It's complicated.  They kept a clean carrot as a reference so I think this is pretty rigorous.
    Gerhard Adam
    Yes, but doesn't the hygiene hypothesis debunk their debunking?  After all, it would predict that a 10 second rule is probably preferable.
    Mundus vult decipi
    Dunno, you spent more time thinking about that question than I spent writing this whole article! :)
    This is hilarious. Earlier I had cleaned my sink with bleach and later I was draining some noodles with a strainer in the same sink and some fell out of the strainer and landed on the porcelain. I grabbed them and threw them back in the strainer with the others before anyone noticed.

    Just do what the raw-milkers the germs probiotics, make up a story about how it's an essential part of your diet and claim that a massive conspiracy of government and "big" corporations invented the theory that such "germs" could be bad for you in the first place.

    I watched a show called "Boardwalk Empire" on HBO this past week. It is set in 1923 and a woman had a miscarriage which the doctor said was likely due to bacterial infection from raw milk.  It should be scary to kooky anti-science people that we knew more in 1923 about public health and pasteurization than they know today.