Is Double-Dipping Really Dangerous?


We’ve all been witness to that “Ewww” moment. You know, the one when someone at the holiday party or family gathering plunks a potato chip into the ranch dip, takes a bite, then goes for a second dip.

It’s called double-dipping, that unacceptable act of social behavior famously depicted in a Seinfeld episode.

Social etiquette notwithstanding, double-dipping also may pose health risks for those next in the dipping line, says Allison Weinmann, M.D., an infectious diseases physician at Henry Ford Hospital.

What Type of Dip is the Worst?

Recent experiments conducted by the food science department of Clemson University compared how much bacteria were transferred from bitten and unbitten crackers by dipping them in water and measuring the solutions’ bacteria content. Overall, solutions that were contaminated by a bitten cracker had about 1,000 more bacteria per milliliter of water than solutions that were contaminated by an unbitten cracker.

The thickness and acidity of the dip also affected how much of the bacteria transferred as well. Water solutions with higher acidity—much like tomato-based salsa, for example — had declining levels of bacteria over time.

Next, the bacteria content of real dips—salsa, cheese dip and chocolate syrup— were tested after being contaminated by bitten crackers. All three dips had no detectable bacteria to start, but bacteria levels rose after exposure to a bitten cracker. Salsa fared the worst, with about 1,000 bacteria per a milliliter of dip compared with about 150 per a milliliter in cheese and chocolate dip. Since salsa is less thick than the other dips, the researchers theorize that a double dip means more bacteria-contaminated salsa will fall back into the container with each dip.

But like the high-acidity water solution, bacteria levels in the acidic, contaminated salsa fell over time—equaling the bacterial content of the other dips two hours later.

Regardless of the type of dip, Dr. Weinmann says double-dippers spread germs that could lead to illnesses like the flu, colds and infections in others.

“Many illnesses may be transmitted from saliva, so sharing your saliva by double-dipping should be avoided,” explains Dr. Weinmann. “My suggestion is to grab your own bowl or plate of chips and dip away.”

To schedule an appointment with a doctor when you’re sick, call 1-800-HenryFord (436-7936) or visit Don’t have a primary care provider? Find one today.

Dr. Allison Weinmann specializes in infectious diseases and sees patients at Henry Ford Hospital.

Categories: EatWell