Before you pucker up, ponder this: There’s something lurking in that kiss.
A study published in the journal Microbiome showed that people share more than saliva during a passionate embrace. In fact, a kiss that lasts more than 10 seconds transfers about 80 million bacteria from one mouth to another, proving that it’s more than a kiss that’s on your lips.
Scientists studied 21 couples between the ages of 21 and 45 who smooched for science. The couples first filled out a questionnaire on their kissing behavior. The researchers then took saliva samples from each couple to examine the overall composition of microbes in their individual mouths.
It turns out that a kiss can change you — or at least nine kisses a day can. Nine is the number of kisses on average that led to couples having similar mouth microbes.
Then the researchers took it one step further to see if they could estimate the number of bacteria exchanged in a single long smooch. They gave one person in each couple a yogurt drink that included two microbes called lactobacillus and bifidobacteria [by-fid-oh-bacteria]. These occur naturally in the mouth in very small percentages. By measuring the percentage of these two bacteria in the mouths of the partners who didn’t drink yogurt, the researchers arrived at the astounding estimate of 80 million bacteria transferred from mouth to mouth.
Before you go rinse with mouthwash in disgust, scientists believe this exchange may have benefits beyond the kiss. Studies have shown that healthy people have a wealth of different microbes in their mouths.
So, you can enjoy those long, tender kisses even more, knowing that they feel good — and they are good for you.