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.
Busting Myths, Irradiating Chips
Okay, so double dipping can transfer some amount of bacteria from one person to another. The same could be said of doorknobs, toilet seats, utensils, and so forth. But is it as bad as Timmy, George’s nemesis in that Seinfeld episode, claims? Thankfully, the hosts of MythBusters were just as intrigued by the episode’s scientific possibilities as Professor Dawson was.
To ensure that any bacteria involved in the hosts’ experiment came directly from their mouths, they had the chips irradiated and made the dip out of sterilized agar and water. Then they compared the results of double dipping with said chips and dip to putting the dip in their mouths and spitting it into a petri dish. The double dipping generated a few bacterial colonies, but that was nothing compared with the world of bacteria growing in the mouth dish. Essentially, they proved that double dipping isn’t the same as “putting your whole mouth right on the dip,” as Timmy suggested.
Don’t Fear the Dipper
The numbers in the Clemson University study sound alarmingly high, but in the grand scheme of things, that amount of bacteria is most likely harmless—especially when you think about how many germs we encounter on a daily basis (though I don’t recommend that you actually think about this). However, some strains of bacteria and viruses are powerful enough to cause infection through very limited exposure, so it’s still best to err on the side of caution when it comes to party snacking. No double dipping is the first rule to follow; even if you don’t care about a little bacteria, recognize that others around you might. No one wants to be the George Costanza of the party.
Professor Dawson likened eating the dip at a party to kissing all of the attendants on the lips. So if the dip is tasty and you’re among trusted friends whose hygienic habits seem acceptable, feel free to snack away. And if you’re among hundreds of people, both friends and strangers, it’s possible that you’re going to run into someone else’s bacteria anyway. When it comes down to it, double dipping doesn’t lead to the explosion of germs that Seinfeld suggested it does, but it does subject you to some degree of bacteria, so it’s good to keep that in mind, especially during cold and flu season. Just don’t let a bowl of dip at a party turn you into a germaphobe. As Adam Savage, cohost of MythBusters, said at the end of his double-dipping experiment, “Besides, what the heck’s your immune system for, anyway?”
Updated December 3, 2010