You're at a party, snacking on chips and dip, when you witness the disgusting: A guest takes a chip, dips it, takes a bite, then dips it right back in the same bowl of seven-layer deliciousness you've been scooping from for the last 30 minutes. Yep, she's a double-dipper. And she's likely been doing it all night—which means you've probably been enjoying a side of her saliva with your tortilla chips.
Sound familiar? Double dipping is a common phenomenon. An informal poll at the Prevention office found that 55 percent of people admit to double-dipping half-eaten chips, pretzels, baby carrots, and other sauce-scooping devices at dinner parties and gatherings.
The other 45 percent had one response for those who do double dip: Ewww…Protesting that mere idea conjures images of dip bowls swarming with bacteria and viruses that could leave them sick in bed for weeks. (Here's how your food can get contaminated even before you eat it.)
What's the truth, though? It's unlikely that eating out of the same bowl as a double-dipper will actually make you sick.
Sure, if the double-dipper has or has recently recovered from the flu, a stomach bug, or a virus like strep throat, it's possible that you could get sick, as long if they're still contagious, said Philip Tierno Jr, PhD, professor of microbiology and pathology at NYU School of Medicine. But that's only a possibility, not a prediction. The likelihood of you actually getting sick is extremely slim, thanks to the bacteria that live in your mouth.
Here's how it works: When someone double dips, they introduce a tiny, microscopic amount of their bacteria—good and bad, alike—into the dip bowl. If your chip or crudité happens to come into contact with their bacteria, there's a chance that it could make it into your mouth. But once there, those bugs will be attacked by millions of bugs in your mouth—and since everyone's bacteria is different, your bugs won't take kindly to any invading bad ones. And because there's way more of your good bacteria in your mouth than bad bacteria that might come from the double-dipper, those bad bugs don't really stand a chance. (Here are the 10 dirtiest foods you can eat.)
If the offending double-dipper is carrying a virus, there's an even smaller chance you'll get sick. Unlike bacteria, which are pretty hearty, most viruses don't live outside the body for very long. A good chunk of cold and flu viruses, for example, will only survive in the dip for about 15 minutes.
The exception, of course, is norovirus, which can live outside of your body for days. Scooping up less than 100 particles of this virus can leave you with your head over the toilet bowl a few hours later.
So since there's still a small chance you'll pick up a virus or a disease-causing bacteria from the small amount a double-dipper adds to a communal bowl, it might be best to avoid eating from a bowl you know has been double-dipped—especially if you know your friends have been sick.