Germ-frosted cake? Researchers say blowing out birthday candles boosts bacteria

Clemson, SC – Wishing against the spread of germs might sound like a buzzkill, but a recent study from Clemson University suggests it could be practical for people who enjoy birthday cake.

For the study, participants ate pizza and then blew out candles on test cakes – Styrofoam circles covered with foil that had vanilla icing spread on top. Each session also included a control sample in which candles were not blown out.

Researchers examined the icing and found that blowing out the candles raised the amount of “bioaerosols in human breath” present on the cake by an average of 15 times.

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“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,” they concluded.

The study was published online May 22 in the Journal of Food Research.

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