One kiss can transfer 80 million bacteria between mouths

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last updated 8 January 2015

The night sky is perfect, the air is crisp, and no one's around. It's time to end your date with a kiss, right? Sure — if you're comfortable swapping 80 million bacteria with those lips, too.

According to a study published Monday in the journal Microbiome, one open-mouth kiss can transfer 80 million bacteria between mouths. Study author Remco Kort tested the bacteria content of 21 couples in the Netherlands before and after a 10-second French kiss and found, quite romantically, "the bacteria on the tongues of couples was much more similar than the oral bacteria of two strangers."

Lest this deter you from accepting a big ol' smooch from your next suitor, the researchers suggest that this prolific sharing of bacteria could actually be healthy. "There are a number of studies that show if the diversity in bacteria increases... this is a good thing," Kort says, because it might help your body build up resistance to other microorganisms. Swoon.