It is one of the most famous and most damning accusations in all of popular culture: “You double dipped the chip! You dipped the chip, you took a bite, and you dipped again!” Actor Kieran Mulroney as “Timmy” levied those harsh words at Jason Alexander’s George Costanza in “The Implant,” a classic episode of Seinfeld that originally aired on February 25, 1993. At the time, Mulroney claimed, “That’s like putting your whole mouth right in the dip!” But is it really? An undergraduate research team at Clemson decided to investigate. Their findings were both multi-faceted and grim.
Testing to see if there is bacterial transfer seems straightforward, but there are more subtle questions to be answered. How does the acidity of the dip affect bacteria, and do different dips affect the outcome? Members of the no-double-dipping enforcement squad, prepare to have your worst, most repulsive suspicions confirmed.
Bitten crackers, the researchers found, transferred “about 1,000 more bacteria per milliliter” when dipped into water, as opposed to unbitten crackers. But what happens when dips of different viscosity acidity, including salsa, chocolate, and cheese, are brought into the mix? Here is what the Clemson team observed:
We found that in the absence of double-dipping, our foods had no detectable bacteria present. Once subjected to double-dipping, the salsa took on about five times more bacteria (1,000 bacteria/ml of dip) from the bitten chip when compared to chocolate and cheese dips (150-200 bacteria/ml of dip). But two hours after double-dipping, the salsa bacterial numbers dropped to about the same levels as the chocolate and cheese.
As for how much people need to freak out about this, on a hypothetical scale of zero to “Timmy,” the report is cagey. Most bacterial types and viruses from the oral cavity, it states, are “harmless.” But some of them cause influenza, pneumonia, tuberculosis, and SARS. Yes, the article specifically mentions SARS. And Typhoid Mary gets a shout out as well. That’s something to consider. So what should one do in the light of this troubling information?
If you detect double-dippers in the midst of a festive gathering, you might want to steer clear of their favored snack. And if you yourself are sick, do the rest of us a favor and don’t double-dip.