The Five-Second Rule
June 25, 2014

The Five-Second Rule

Potentially adding to my friends’ continued joke of my “lack of a true childhood,” a joke that mostly centers around cartoon shows and movies I have never seen, music I never heard, or places I never went, I had never heard of the five-second rule until I was well into my teenage years. The idea that when food is dropped onto the floor you have approximately five seconds to pick it up before it becomes wholly contaminated is a premise I always found a little bit weak. Sure, I can see picking a piece of still dry hard candy up off a relatively clean floor, rinsing it off, and still eating it, but not things like hotdogs or other meat, cheese, or any food that has a moist texture. Maybe it came from growing up with a number of nurses in the family, but this was never something I put any stock in and often found myself rolling my eyes when I would see others use this logic.

So is it true? Well, according to Jorge Parada, MD, MPH, FACP, FIDSA, medical director of the Infection Prevention and Control Program at Loyola University Health System, no. “A dropped item is immediately contaminated and can’t really be sanitized,” Parada said. “When it comes to folklore, the ‘five-second rule‘ should be replaced with ‘When in doubt, throw it out.’”

Any item that comes into contact with any surface picks up bacteria. That is not in question. It’s how much and of what kind that matter. Those things depend on the object that has been dropped and what the item was dropped on. For example, cleaning off a dropped hotdog will certainly reduce the amount of bacteria it picked up after being dropped, but it will not get rid of all of them. According to Parada, who does admit to occasionally using the five-second rule depending on circumstances – meaning what is involved – “Maybe the dropped item only picks up 1,000 bacteria but typically the innoculum, or amount of bacteria that is needed for most people to actually get infected, is 10,000 bacteria. Well, the odds are that no harm will occur. But what if you have a more sensitive system, or you pick up a bacteria with a lower infectious dose? Then you are rolling the dice with your health or that of your loved one.”

Parada also discusses a parent using their own mount to “clean off” a dropped baby pacifier. (Really? Do people actually do this?) This is also a false assumption. If anything, according to Parada, the parent is actually making it worse by not only exposing them to the bacteria first, but then exposing their baby not only to the bacteria of whatever the pacifier was dropped on, but also their mouths as human mouths are far from the most sterile surface.

According to Parada, “There actually is certain research that supports the importance of being exposed to bacteria at critical times in a child’s development. But I believe this development applies to exposures of everyday living. I do not advocate deliberately exposing ourselves to known contaminants. That would probably be a misplaced approach to building up our defenses. If you want to be proactive in building up your defenses, eat right, exercise, and get adequate sleep – – and remember to get your vaccines.”

Well said, doctor. Well said.

On a final note, cleaning off something for your baby with your own mouth? Really?

Image Credit: Thinkstock

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