How Risky Is Double Dipping?

The practice of double-dipping strikes most people as gross and unsanitary. But does it really increase your risk of infection? Nutrition Diva investigates the science behind the Seinfeld episode.

Monica Reinagel, MS, LD/N, CNS
3-minute read
Episode #362

Even if you don't remember the infamous Seinfeld double-dipping episode, the idea of someone dunking a chip or carrot into a communal bowl of dip or salsa after they've already taken a bite probably strikes you as a little gross. But is this instinctive aversion to double-dipping scientifically sound?

A few years ago, researcher Paul Dawson of Clemson University decided to find out just how unsanitary the practice of double-dipping is. (Because what is nutrition science for, if not to fact-check sitcoms?)

In his study, Dr. Dawson found that double-dipping does, in fact, transfer bacteria from your mouth to the dip, where it can then be picked up and ingested by the next unwary dipper … even two hours after the original double dip.

As Dr. Dawson expressed it to me in an email, "Sharing a dip with someone that is double dipping is a little like kissing them."

That may not seem like a big deal if you're sharing a dip with your loved ones. But if you are going to any big holiday parties this week where dip is being served, you may want to scan the crowd to see if everyone in the room looks like someone you'd be willing to swap a little spit with. If not, you might want to steer clear of the dip. 

What's in Your Mouth?

The fact that double-dipping transfers bacteria from the mouth of the dipper into the dip may strike you as gross but it’s not necessarily dangerous. The human mouth harbors anywhere from 500 to 1,000 different types of bacteria, but most of them are completely harmless. Some are even beneficial.


About the Author

Monica Reinagel, MS, LD/N, CNS

Monica Reinagel is a board-certified licensed nutritionist, author, and the creator of one of iTunes' most highly ranked health and fitness podcasts. Her advice is regularly featured on the TODAY show, Dr. Oz, NPR, and in the nation's leading newspapers, magazines, and websites. Do you have a nutrition question? Call the Nutrition Diva listener line at 443-961-6206. Your question could be featured on the show.