Australasian Science: Australia's authority on science since 1938

The Unromantic Truth About Kissing

purmar/iStockphoto

Credit: purmar/iStockphoto

By Magdeline Lum

When couples kiss intimately for 10 seconds they transfer 80 million bacteria.

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Up to 80 million bacteria are transferred during a 10-second kiss, and couples that kiss up to nine times a day have similar communities of oral bacteria according to research published in Microbiome.

This number pales in comparison to the 100 trillion microbes that live in our bodies and are essential for digesting food and preventing disease. The human mouth is home to around 700 varieties of the bacteria living in the human body.

The study by researchers from the Micropia museum of microbes in Amsterdam and the Netherlands Organisation for Applied Scientific Research (TNO) quizzed 21 couples about their kissing behaviour, including their average intimate kiss frequency, and also collected swab samples to investigate the bacteria living on their tongues and in their saliva. For the purposes of the study, an intimate kiss was defined as “involving full tongue contact and saliva exchange”.

The results showed that when couples kiss at relatively high frequencies their salivary bacteria became similar. On average it was found that at least nine intimate kisses per day gave couples significantly shared salivary microbiota.

“Intimate kissing involving full tongue contact and saliva exchange appears to be a courtship behaviour unique to humans and is common in over 90% of known cultures,” said lead author Remco Kort from TNO’s Microbiology and...

The full text of this article can be purchased from Informit.