WASHINGTON — Sometimes a kiss is more than just a kiss. Scientists say
they’ve found that a 10-second French kiss can transfer up to 80 million
bacteria.
“Intimate kissing involving full tongue contact and saliva exchange appears to
be a courtship behavior unique to humans and is common in over 90 percent of
known cultures,” said microbiologist and professor of microbial genomics at
Amsterdam’s VU University Remco Kort, who led the study published Sunday in
the journal Microbiome.
“During a kiss, you get exposed to many bacteria, but only a minor fraction of
them are able to colonize the human body,” Kort said.
The small study involved 21 couples, including two gay couples, Live
Science reports.
To measure the bacteria, Dutch researchers took samples of the bacteria on
each person’s tongue. And they took spit samples to gauge their salivary
bacteria both before and after a kiss.
Researchers had one member of each couple drink a yogurt drink that contained
Lactobacillus andBifidobacteria. After a 10-second intimate
kiss, they took a sample of the bacteria in the mouth of the person who did
not drink the yogurt and made their calculations.
The outcome was the the bacteria in the partner’s mouth increased threefold,
which amounts to about 80 million new bacteria, the researchers said.
There are more than 700 types of bacteria that live in people’s mouths.
The research found that the more you kiss, the more similar you are to your
partner, at least in terms of bacteria.
The study results are being used as part of an interactive exhibit at
Micropia, the world’s first museum of microbes in Amsterdam. Couples there can
kiss and a sensor tells them how many bacteria will likely transfer.
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