Double dipping. It’s divided friends, families, and lovers. It’s caused unfortunate riffs between otherwise amicable dining companions. Double dippers believe it’s perfectly acceptable to dunk their chip, take a bite, then dip a second time.


But whether we’re talking party snacks or sexual acts, double dipping is for unhygienic losers. And now science is here to back us up.

According to new research from Clemson University in South Carolina, dips like salsa, queso, and chocolate take on tons of bacteria when subjected to double-dipping. That being said, the amount of bacteria transferred as a result of double dipping depends on the thickness and acidity of the dip. Professor of Food Science Paul Dawson explains,

How dirty is your dip? We found that in the absence of double-dipping, our foods had no detectable bacteria present. Once subjected to double-dipping, the salsa took on about five times more bacteria (1,000 bacteria/ml of dip) from the bitten chip when compared to chocolate and cheese dips (150-200 bacteria/ml of dip). But two hours after double-dipping, the salsa bacterial numbers dropped to about the same levels as the chocolate and cheese.

We can explain these phenomena using some basic food science. Chocolate and cheese dips are both pretty thick. Salsa isn’t as thick. The lower viscosity means that more of the dip touching the bitten cracker falls back into the dipping bowl rather than sticking to the cracker. And as it drops back into the communal container, it brings with it bacteria from the mouth of the double-dipper.

Salsa is also more acidic. After two hours, the acidity of the salsa had killed some of the bacteria (most bacteria don’t like acid). So it’s a combination of viscosity and acidity that will determine how much bacteria gets into the dip from double-dipping.

Here’s a nifty graph that illustrates the bacterial numbers in the salsa, chocolate, and cheese dip.


(Graph via Paul Dawson/The Conversation)

No matter if you’re grubbing on salsa or queso at a holiday party this season, it’ll obviously serve you well to steer clear of double-dippers and any foods they’ve touched. #StayWoke

And if you yourself are that insufferable double dipper, well, COME THE F*CK ON.

[via Uproxx, The Conversation]