Double-Dipping Is a No-No

Unless you want to partake in a 10,000 Bacteria Buffet.

It’s the second most noxious party faux pas, after getting drunk and hitting on your boss’s wife: double-dipping. Made famous by the Seinfeld sketch in which George Costanza is yelled at by his girlfriend’s brother while at a funeral reception (the brother, aghast, accuses George: “You dipped a chip, you took a bite—and you dipped again!”), double-dipping is one of those habits that some people deplore and others shrug off.

Now, just in time for Super Bowl Sunday, a study has been released offering scientific evidence that those who deplore double-dipping have been right all along. In the study, a Clemson University food microbiologist (incidentally, the same guy who disproved the five-second rule) had nine students take a bite of a wheat cracker and then dunk it in a dip for three seconds. “There were six test dips: sterile water with three different degrees of acidity, a commercial salsa, a cheese dip and chocolate syrup,” the New York Times reports (chocolate syrup?!). “On average, the students found that three to six double dips transferred about 10,000 bacteria from the eater’s mouth to the remaining dip.” The article continues:

Each cracker picked up between one and two grams of dip. That means that sporadic double dipping in a cup of dip would transfer at least 50 to 100 bacteria from one mouth to another with every bite.

The kind of dip made a difference in a couple of ways. The more acidic water samples had somewhat fewer bacteria, and the numbers of bacteria declined with time. But the acidic salsa picked up higher initial numbers of bacteria than the cheese or chocolate, because it was runny. The thicker the dip, the more stuck to the chip, and so the fewer bacteria were left behind in the bowl.

Ten thousand bacteria! The rules for Super Bowl are clear: tiny chips, thick dip, and NO DOUBLE-DIPPING.

Posted by Traci Vogel | Friday, February 1, 2008 at 12:30pm | 3 comments
Tagged with: double dipping, seinfeld, george costanza, scientific study, clemson university, party dip, paul dawson

Saving the Five-Second Rule

According to actual scientists, our favorite justification for picking up and eating dropped food may have some basis in reality.

The five-second rule (or three-second rule, depending on whom you ask) was publicly discredited a few months ago after an incident involving the Ohio State basketball head coach, a piece of chewing gum, and the ground. But an exciting new study contradicts that fateful Chicago Tribune story, and Harold McGee is spreading the news, potentially rescuing the five-second rule from the dustbin of schoolyard lore.

As he explains, researchers at Clemson University conducted “a thorough microbiological study” of the rule, which stipulates that if you pick up a dropped piece of food within five seconds, you can eat it without worrying about germs. While it may have originated on the playground, the rule actually has a basis in reality: The researchers found that the longer they let food rest on bacteria-painted surfaces (they used a salmonella “broth”), the more germs the food collected. The difference is vast, in fact:

On surfaces that had been contaminated eight hours earlier, slices of bologna and bread left for five seconds took up from 150 to 8,000 bacteria. Left for a full minute, slices collected about 10 times more than that from the tile and carpet, though a lower number from the wood.

We don’t actually eat off of surfaces that have been bathed in salmonella all that often (or for that matter E. coli, which another five-second-rule study had used as a test bacterium), so our floors and countertops are generally far less contaminated. Still, McGee cautions, a dropped piece of food on a normal floor “would be likely to pick up several bacteria.” Some strains of salmonella can cause illness with as few as 10 bacteria, and the deadly strain of E. coli with fewer than 100, so just watch where you go smearing your raw chicken juices.

But if you clean off your counters after preparing meat or eggs and don’t make a habit of tracking dog poop all over your floors, the five-second rule will probably keep you safe. Certainly safer than if you let dropped food linger any longer before putting it in your mouth—and now there’s science to prove it. Thank you, science!

Posted by Christy Harrison | Monday, May 14, 2007 at 2:32pm | 1 comment
Tagged with: five-second rule, harold mcgee, new york times, chicago tribune, ohio state, clemson university, bacteria