The 2017 study had also pointed towards the same thing.
Cake is the most important part of a birthday party. People across the world celebrate the occasion by blowing the candles places on a birthday cake. But an expert has said that the process can lead to transfer of thousands of bacteria. Paul Dawson, professor of food safety at Clemson University in the US, told CNN that a study conducted by his team found "about 1,000" bacteria being released in a single blow. The culprits, according to Professor Dawson, are water droplets that come out when we blow the candles.
"We found about 1,000 bacteria when someone did blow and virtually no bacteria on surface that had not been blown on," said the food safety expert.
"My advice would be if someone's blowing the candles out, especially if they are sloppy doing it, when I get a slice I would scrape the top layer off," Professor Dawson added.
He, however, said not everyone needs to worry about getting an infection from consuming such a cake immediately.
"Probably there is very little danger in eating birthday cake that has been blown on because we are with other people all the time. The real concern is with the immunocompromised and those who are sick or elderly, or have a disease," Professor Dawson told CNN.
In 2017, a study published in Canadian Centre of Science and Education highlighted such a risk by studying the entire process in detail.
It also pointed towards the "bioaerosols in human breath" as a source of bacteria transferred to cake surfaces.
"To test aerosol transfer to cake, icing was spread evenly over foil then birthday candles were placed through the foil into a Styrofoam base. After consuming pizza, test subjects were asked to extinguish the candles by blowing. Icing samples were sterilely recovered then surface plated, to determine the level of bacterial contamination. Blowing out the candles over the icing surface resulted in 1400% more bacteria compared to icing not blown on," said the study.
It could lead to transfer of bacteria and other micro-organisms from the respiratory tract of a person blowing out candles to food consumed by others.