If Science can’t settle this one…


I always enjoy seeing contradictory results from peer-reviewed science.  The simpler the topic the better.

Is the science settled on this or not?  The latest paper says it should be changed to the thirty-second rule which contradicts as earlier paper which said the zero-second rule should always be applied.

If I favor the thirty-second rule does that mean I also believe the Earth is flat and I am anti-science?  Or is it the other way around.  If two more papers come out saying the zero-second rule is correct, does that become a consensus and mean that only anti-science people pick up an M&M that falls on the ground?  Would anybody take scientific papers on the five-second rule and apply them in their lives?

I believe MythBusters  tested double dipping and found that dip already has so much bacteria in it that it wasn’t possible to determine the impact of double dipping using food.  That had to use sterile gelatine to perform the tests.

Disputes in Science: The Five-Second Rule

Posted by Ross Pomeroy at Mon, 22 Aug 2011 16:51:00

A laundry list of contentious issues litters the annals of science. Topics such as evolution, climate change, the beginning of human life, and heliocentrism have all spurred vehement and occasionally violent disputes.

Now, it is time to add another issue to this list. Debated on television, in newspapers, between friends, on college campuses, and around the dinner table, this issue has potentially sparked more controversy than the combined quarrels from the world’s vast assortment of Twitter accounts. I’m talking, of course, about the “Five-second Rule.”

The Five-second Rule states that any morsel of food that is dropped on the ground will not be contaminated with bacteria if it is picked up within five seconds of being dropped. Numerous scientific studies have put this rule to the test.

One of the first documented studies on the Five-second Rule occurred in 2003 at the University of Illinois. Researcher Jillian Clarke dropped gummy worms and cookies on floor tiles inoculated with E. coli bacteria and left them there for five seconds. Clarke found that “In all cases, E. coli was transferred from the tile to the food…”

However, four years later, Connecticut College seniors Molly Goettsche and Nicole Moin decided to put the Five-second Rule to the test once again. Stating that the previous U of I study was “not representative of what actually happens,” the scientists sought to scrutinize the rule in an everyday environment. Goettsche and Moin dropped apple slices and skittles at various dining locations on their college campus and allowed the food to sit for five, ten, thirty, sixty, and 300 seconds. The researchers then swabbed the foods and placed the scrapes onto agar.

Goettsche and Moin’s research turned out a very different result than Clarke’s. “The women found no bacteria were present on the foods that had remained on the floor for five, ten, or thirty seconds.”

Five_second.pngGreg Williams / Wikimedia Commons

So here we are, with two well-executed studies and the legitimacy of the Five-second Rule still left in the balance. Unfortunately, it may remain that way. The application of the rule vastly depends on such variables as food type, floor type, and the subject’s level of germophobia.

While doctors may argue that “The Five-second Rule probably should become the zero-second rule,” others, who may be less germophobic, less inclined to waste, or simply hungrier, will probably agree with Goettsche and Moin’s assessment that the Five-second Rule should be changed to the Thirty-second Rule. (RealClearScience’s editor, Alex Berezow, a PhD in microbiology, has even written on the merits of eating dirt.)

Though science does its best to seek out answers to life’s little mysteries, it may not be the best discipline for those seeking comfort in certainty. Controversial debates are a mainstay in this branch of knowledge, and with heated issues such as the Five-second Rule, science is sure to remain a source of contention for mankind

Posted in General by inconvenientskeptic on August 23rd, 2011 at 8:22 am.

8 comments

This post has 8 comments

  1. Eric Anderson Aug 23rd 2011

    This is great — thanks for the post!

  2. There is a crucial difference between the two studies.One was better measured than the other.

    “Researcher Jillian Clarke dropped gummy worms and cookies on floor tiles inoculated with E. coli bacteria and left them there for five seconds. Clarke found that “In all cases, E. coli was transferred from the tile to the food…””

    The floor was DELIBERATELY inoculated.Thus it was no surprise that the gummy worms and cookies would get contaminated.

    Versus,

    “Goettsche and Moin dropped apple slices and skittles at various dining locations on their college campus and allowed the food to sit for five, ten, thirty, sixty, and 300 seconds. The researchers then swabbed the foods and placed the scrapes onto agar.

    Goettsche and Moin’s research turned out a very different result than Clarke’s. “The women found no bacteria were present on the foods that had remained on the floor for five, ten, or thirty seconds.””

    No mention of inoculating the floors.No mention of determining what level of bacterial contamination are present.

    I see no reason why I should accept their research as being robust.They failed to at least get a measure of present levels of bacteria on the floors.

    Thus we have no idea if one or more of the places,where they dropped the apples and skittles pieces.Had any measurable level of bacteria present to contaminate the food samples they had dropped.

    While Clarke at least made sure there was a KNOWN level of bacteria on the floor.

    LOL

  3. inconvenientskeptic Aug 25th 2011

    Ahh, but the G&M paper found that bacteria was present when it remained on the floor longer than 30 seconds, which does indicate that they did find bacteria on the samples of 60 and 300 seconds.

    They did their test under real world conditions and we have no knowledge of the floor conditions that the Clarke paper used. Just how much E. Coli was placed on the floor? Was it enough to cause the floor to be wet, because everyone knows that makes the 5 second rule, the 0 second rule.

    😀

  4. Yes they did say that.But what variety of bacteria was it?

    Maybe a weaker strain?

    Clarke has a known aggressive bacteria type on the floor.They did theirs in this manner:

    “The next step was sterilizing the tiles and inoculating them with E. coli, then placing 25 grams of cookies or gummies on the tiles for 5 seconds. In all cases, E. coli was transferred from the tile to the food, demonstrating that microorganisms can be transferred from ceramic tile to food in 5 seconds or less. More E. coli were transferred to gummy bears from smooth tiles than from rough tiles.”

    I agree that Clarke’s work was a deliberate laboratory set up.While the other research was more open ended.

  5. inconvenientskeptic Aug 25th 2011

    So let me ask the million dollar question.

    Will you stop (assuming you have in the past) following the 5-second rule?

    Or is the laboratory result sufficient to change your behavior.

    The other aspect which has not been discussed is how much bacteria is on everything anyway. Most cleaning reduces counts by 4-5 orders of magnitudes, but that still leaves millions of bacteria.

    While not a paper, the floor doesn’t make the top 10 list, but the kitchen counter does. 🙂

    http://www.theepochtimes.com/n2/life/your-homes-10-germiest-places-60336.html

  6. I never thought about a 5 second rule.

    The research does not impress me.They leave out too many variables.That should have been considered.

    I think the toilet is even worse.

  7. inconvenientskeptic Aug 26th 2011

    I agree.

    I like these type of articles though. They show how often science does reach different conclusions and how hard it is to say that the science is settled.

    For something like global warming, it is absurd to make such a statement. Yet those that do, get labelled as anti-science. There is the key indicator that politics has taken over.

  8. Sheri Kimbrough Sep 10th 2011

    I never really thought of this as a science experiment. There may be bacteria, there may not, but the rule seemed more something that people just say and really never put any stock into it. If something falls on the floor, whether or not a person picks it up and eats it would seem to fall more into the psychology realm–as was mentioned, how afraid of germs is the person, how hungary etc. As for whether or not the research would change my behavior toward the dropped food, it seems unlikely. It does illustrate how difficult it can be to reach a “settled” conclusion in science, as you noted.

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