Here is a little something to think about before you lean in to smooch your sweetie beneath the mistletoe this holiday season: with just one kiss you could be sharing millions bacteria with your special someone, according to a new study conducted by researchers in the Netherlands.
All it takes is about 10 seconds of lip locking to swap up to 80 million microbes, say researchers, who worked with nearly two dozen couples to determine the effects of “intimate kissing” on the bacterial environment in the mouth. After the couples answered several questions about how often (and for how long) they kissed each day, one person from each duo was asked to drink a probiotic beverage containing beneficial bacteria such as Lactobacilli and Bifidobacteria before kissing his or her partner.
After taking an oral swab of each participant’s mouth, researchers determined that the amount of probiotic bacteria in the saliva of the receiver (the participant who did not drink the probiotic beverage) was, on average, three times higher—indicating about 80 billion bacteria had been exchanged during just 10 seconds of kissing. From their findings, researchers also determined that couples who kiss as often as nine times a day have oral bacterial communities that are roughly identical.