Blowing out candles can increase the amount of bacteria on the icing of cake by about 1,400%, according to a recent study.
A 1,400% increase means that if there was even just one bacterium on the cake at first, there are 1,400 bacteria on it after someone blows out the candles.
Just the air you blow at the candles is apparently a pretty gross threat. Blowing out candles spreads tiny drops of saliva and tons of bacteria onto the cake.
The research included pizza and cake because the scientists wanted to simulate the feeling of a real birthday party.
Researchers compared the icing on two cakes, one where candles were blown out and another where they were not.
Testing the cakes that had been blown on had massively more bacteria than the cakes that had not.
They found blowing on the candles increased the amount of bacteria on the cake by 1,400 percent.
Due to the transfer of oral bacteria to icing by blowing out birthday candles, the transfer of bacteria and other microorganisms from the respiratory tract of a person blowing out candles to food consumed by others is likely.
The results of this study means that you’ve likely been eating bacteria from the mouths of every friend or family member who had a birthday for your whole life, but that bacteria probably wasn’t harmful.
“It’s not a big health concern in my perspective,” study co-author Paul Dawson, Department of Food, Nutrition and Packaging Sciences, Clemson University, USA. “In reality, if you did this 100,000 times, then the chance of getting sick would probably be very minimal.”
The results may help raise awareness of possible health risks associated with birthday celebrations and encourage others to take steps toward preventing the spread of bacteria.
The study was published in the Journal of Food Research.