A 10-second “intimate kiss” can transfer a whopping 80,000,000 bacteria from one mouth to another, according to a new report in the journal Microbiome. The related study was completed by Dutch researchers at Artis Royal Zoo in Amsterdam and involved 21 couples.

The more often a couple kissed, the more similar the bacteria in their saliva samples, with the researchers concluding that couples needed to kiss at least nine times a day to achieve notably lower bacteria levels. The men said they kissed their partners an average of 10 times a day, while the women recalled kissing only five times a day. The researchers concluded that the men were most likely exaggerating the frequency of their romantic encounters. Read more…