George Costanza was wrong. This isn’t the first time that statement’s been uttered and it certainly won’t be the last, as long as Seinfeld continues to be culturally relevant. (And how could it not be?) In one infamous episode, George is standing in front of the buffet table at a funeral reception, snacking on chips and dip. An onlooker spies him dipping a chip, taking a small bite, and then going for more dip. “You double dipped a chip! … That’s like putting your whole mouth right in the dip,” the witness admonishes. George being George, he continues double dipping, and this being Seinfeld, a fight breaks out between the two of them in the middle of the reception.
Did people ever even talk about double dipping before this scene? Prior to watching the show, I’d never considered its potential bacterial consequences or social unacceptability. Frankly, I was more concerned with getting the most dip mileage out of every chip, which probably led to my committing the aforementioned offense from time to time. Now I view bowls of salsa and onion dip at parties with some suspicion, but is my skepticism based on a real threat? Was George actually spreading dangerous germs with every double dip?
Seinfeld Enters the Science World
Paul Dawson, a professor at Clemson University, had the same question while watching the Seinfeld episode. He decided to make a study of it, using wheat crackers with dips of various consistencies—salsa, cheese dip, chocolate syrup, and so forth. He and his fellow researchers asked participants to bite part of a cracker, dunk it for three seconds into a tablespoon of dip, and then do the same thing with a fresh cracker. Each person double dipped anywhere from three to six times. Dawson and company then checked the dip for traces of bacteria.
The results, which were published in a 2009 edition of the Journal of Food Safety, found that double dipping added almost ten thousand bacteria to the dips. The crackers held about one or two grams of dip, which meant that fifty to one hundred bacteria on average could be transferred that way. The researchers also found that the consistency of each dip affected its bacterial impact. Because salsa’s more runny than cheese or chocolate dip, when an already bitten chip scoops it up, some runs off the chip (which holds lingering bacteria from the double dipper’s mouth) and back into the bowl, increasing the salsa’s bacterial content. However, salsa had a lower bacterial level than the others after sitting out for a couple of hours.
