The next time you close your eyes and lean toward your birthday cake, I hope you're wishing for something disgusting, because that's what you'll get after you blow out the candles.
According to a new, stomach-churning study, the seemingly innocuous tradition of exhaling forced air to put out a bunch of tiny fires on top of your cake can actually increase the amount of bacteria on the icing by fourteen times. Everyone's birthday is ruined! You're welcome!
In the study, which was recently published in the Journal of Food Research, researchers at Clemson University tried their best to approximate a teen's birthday party, lining 17 candles on top of a faux foil-and-Styrofoam birthday cake, then spreading Betty Crocker vanilla icing over it. The 11 test subjects took turns blowing those candles out, and, so they'd have the full birthday experience, the subjects were instructed to eat pizza before exhaling as hard as they could. ("We thought [pizza] might help the salivary glands get going," lead study author Paul Dawson said.)
Samples of the icing were spread on agar in petri dishes and the researchers waited 48 hours before discovering the gross truth about what's in our mouths. "Blowing out the candles over the icing surface resulted in 1,400 percent more bacteria compared to icing not blown on," the authors wrote. "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."
Dawson told The Atlantic that despite how nasty his findings were, it doesn't mean that you'll be getting some kind of communicable disease for your birthday. "It's not a big health concern in my perspective," he said. "In reality if you did this 100,000 times, then the chance of getting sick would probably be very minimal." He did suggest not inviting sick individuals to take a shot at the candles, so sorry, Typhoid Mary, but the party has been cancelled forever.
Interestingly, the study says that the practice of blowing birthday candles out could be traced back to the Ancient Greeks, who took cakes with lit candles to the temple of Artemis, the goddess of the hunt. I don't know if that's better or worse than carrying them over to the temple of Hygieia, the goddess of hygiene.
Regardless of what Dawson says, maybe we should all stick to cupcakes. No candles necessary.