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Did you double-dip that chip!?
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Who knew that Seinfeld would spawn so much science? As Sheril already mentioned, she frequently gets asked about an episode of the show when she tells people she's a marine biologist. Now, apparently, the show has also inspired a study on the microbiology of "double-dipping."
On the episode in question (which also happens to be the Teri Hatcher "they're real, and they're fabulous" one; I have the video over at Aetiology), George is at a wake and eating chips. He dips the chip into the dip, takes a bite, and then dips it back in--outraging his date's brother, who tells him that double-dipping is "like putting your whole mouth right in the dip." So, a scientist at Clemson decided to test that idea with his students:
The team of nine students instructed volunteers to take a bite of a wheat cracker and dip the cracker for three seconds into about a tablespoon of a test dip. They then repeated the process with new crackers, for a total of either three or six double dips per dip sample. The team then analyzed the remaining dip and counted the number of aerobic bacteria in it.There were six test dips: sterile water with three different degrees of acidity, a commercial salsa, a cheese dip and 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. 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 research hasn't yet been published, but the take-home message (especially for Superbowl parties this weekend): unless you'd feel comfortable kissing everyone at the party, don't double-dip!
4 Comments
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January 31, 2008 6:55 AM
FutureMD
I'm honestly curious here: is 50 to 100 bacteria per bite really significant when the mouth contains billions of bacteria per square centimeter? How large of an inoculum would be required to set up a Neisseria infection in a healthy mouth? Chances are the bacteria transferred are just normal flora anyway, right?
I apologize for the double post (I posted this in Mz.(Dr?) Smith's other blog).
January 31, 2008 6:58 AM
FutureMD
Also, this being put under Department: culture is awesomely appropriate.
January 31, 2008 9:46 AM
jen_m
Depends on the bacteria in question. The urethral ID50 for gonococcus is 1000 bacteria, but I don't think oral infectivity has been examined that closely. Infection with Campylobacter jejuni, a major player in grody foodborne infections, has been induced with 500 organisms, but unless your fellow partier had *just* yakked, you wouldn't be at particular risk, given the organism mostly hangs out in the gut.
I think you're right, that most of the organisms transferred would be benign flora, but the implications for viral transmission are a little more ominous. Herpesviruses, rhinoviruses and noroviruses come to mind as potentially icky and quite transmissible with double-dipping.
Mind you, I'd also like to know how many bacteria are transferred from hand to chip bowl during the grubbing-and-grabbing phase of the transfer.
UGH.
May 22, 2008 4:31 PM
jonny
I THINK I FOUND HOW TO RIP OPEN A WORMHOLE TO TRAVEL THE SPEED OF LIGHT!!!!!!(or make one hell of a nuke!) email me email me email me!!!!!!!!!!!!!!! i will tell you my theory!!!!!!!!!! i can revolutionize space travel!!!!!!!!
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