It may be time to bust out the Listerine. A new study out of the Netherlands has found that a 10-second kiss can transfer as many as 80 million new bacteria into a person’s mouth. And there’s the collective yuck. Thanks science.

There is some good news, though. Couples that kiss at least nine times a day have similar microbiomes in their mouths. Before you turn away from the next kiss, you should know there are over 100 trillion microorganisms that live in or on our bodies. With that fact, 80 million is sounding pretty small.

Remco Kort, the co-author and professor of microbial genetics at the University of Amsterdam commented on the study. “During a kiss, you get exposed to many bacteria, but only a minor fraction of them are able to colonize the human body.”

How the study was conducted is good for a laugh. Researchers found 21 couples walking around the Artis Royal Zoo. That had to be an interesting conversation. So, we want to watch you kiss, swab your mouth and follow up with a questionnaire. Wait, what?

The researchers also took spit samples to measure salivary bacteria before and after a kiss. Only scientists could make kissing sound disgusting. With 700 types of bacteria in the mouth, researchers found that couples that kiss more often had similar oral microbiota.

What the study is unclear on is how this affects a person’s health. While the similar microbiomes is an important step, a long-term study would be needed to see if there’s any health impact. A final test, that reached the 80 million figure, involved one partner drinking a yogurt drink containing Lactobacillus and Bifidobacteria. Toss in the 10-second kiss, and the partner’s level of bacteria increased three-fold.

If you happen to be in Amsterdam for reasons other than marijuana, check out the world’s first museum on microbes – Micropia. This study is being turned into an interactive exhibit with the help of study author, Remco Kort. Couples can kiss next to a sensor, that will determine the type of kiss and approximately how many bacteria were transferred.

The study is in the November 16 issue of the journal, Microbiome.

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