We knew that French kissing leads to ample bacteria exchange between the two individuals, but a new research tells us approximately how many. It takes just a 10 second kiss to transfer up to 80 million bacteria. Some would say it is gross, others will definitely continue the practice of bonding, now clearly aware that during the process, their salivary microbiota tends to become similar. It takes only nine kisses per day to get to have the same oral microbiota, which is composed of around 700 types of bacteria.
Researchers from Netherlands Organisation for Applied Scientific Research (TNO) performed a study with the help of 21 couples. After the couples reported their daily number of kisses, researchers took swab samples from their mouths to look closely at the result of the interaction.
“Intimate kissing involving full tongue contact and saliva exchange appears to be a courtship behavior unique to humans and is common in over 90% of known cultures,” said Prof. Remco Kort, lead author of the study. “Interestingly, the current explanations for the function of intimate kissing in humans include an important role for the microbiota present in the oral cavity, although to our knowledge, the exact effects of intimate kissing on the oral microbiota have never been studied,” he added.
On a side note, men reported a much higher frequencies of kisses per day compared to the women from the same couples. While men said they kiss their partners ten times a day on average, women declared just five kisses per day.
Further on, scientists asked one member of each couple to drink a probiotic mixture with a traceable bacterial population. After they timed ten seconds kisses, other measurements have been taken. The receiver had three times as much bacteria in his or her saliva after the kiss. About 80 million bacteria originated in the probiotic drink.
Bear in mind that the human microbiome contains more than 100 trillion microorganisms living in our bodies.
The experiment proved that the tongue has interesting properties in the management of bacterial populations. While the saliva microbiota changes more as the number of kisses increases, the tongue microbiota is less susceptible to short term dramatic changes. The discovery that just some of the bacteria stick to the tongue will have useful implications in the treatment of people with bacterial problems, according to Prof Kort.