Jakarta, Indonesia Sentinel — Kissing for just 10 seconds can transfer up to 80 million new bacteria into a person’s mouth, according to a study from the Netherlands. Published in the journal Microbiome, the research also found that couples who kiss at least nine times a day tend to share similar communities of oral bacteria.
“When you kiss, you’re exposed to a vast number of bacteria, but only a small fraction of them can colonize the human body,” said Remco Kort, a microbiology professor at the University of Amsterdam, as reported by.
The mouth hosts an ecosystem of over 700 types of bacteria, making it one of the body’s most densely populated microbial habitats. The broader microbiome—composed of more than 100 trillion microorganisms living throughout the human body—is vital for digesting food, synthesizing nutrients, and preventing disease.
While shaped by genetics, diet, and age, the study found that the microbiome is also influenced by the people with whom we interact, especially close partners through kissing.
Bacteria and Kissing
Researchers from Micropia and TNO in the Netherlands studied 21 couples by asking them to complete a questionnaire on their kissing habits over the past year, including how often and how long they kissed. The team then took sample from their saliva and tongue swabs to analyze the couples’ oral microbiota before and after kissing.
The results revealed that couples who kissed intimately and frequently—averaging at least nine times daily—shared significantly similar saliva microbiota.
To further assess the transfer of bacteria, one participant in the study consumed a yogurt containing specific probiotic bacteria, such as Lactobacillus and Bifidobacteria, which are not commonly found in the mouth.
The participant then kissed their partner for 10 seconds, transferring not only the probiotics but also approximately 80 million additional bacteria.
The study also noted that the more frequently couples kissed, the more their oral bacteria resembled one another. “The tongue serves as a resting place for bacteria, where they form communities and inhabit the surface for an extended period,” Kort explained.
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Path Schloss, a microbiology professor at the University of Michigan who was not involved in the research, commented that while frequent kissing leads to similar oral microbiomes between partners, it remains unclear whether this bacterial exchange benefits health.
The findings are featured in the kiss-o-meter exhibit at Micropia, the world’s first microbial museum in Amsterdam. Visitors can experiment by kissing and then use a sensor to measure the type of kiss and the number of bacteria transferred during the interaction.
(Raidi/Agung)
