I can identify the exact moment when my relationship with birthday cake changed forever, and it was last week, when I read a study titled “Bacterial Transfer Associated with Blowing Out Candles on a Birthday Cake.”
Of course, the more cautious (aka germophobic) among us have already thought about it in gruesome detail. One colleague said she scrapes off the top layer of frosting, a habit that suddenly made perfect sense but which I for some reason had never before considered. I had been living in ignorant, saliva-splattered bliss.
Intellectually, I knew it was fine. I’ve consumed countless slices of sheet cake finely misted with spit and suffered no particular consequences—and yet, the thought of eating another now sent visceral disgust through my body.
So I called up Paul Dawson, a professor of food safety at Clemson University and one of the authors of this study, to ask why someone would want to ruin birthday parties.
Dawson said the idea for the study came from his teenage daughter. But he’s also conducted a whole set of studies around common questions in food safety with his undergraduate students, as a way of engaging them in original scientific research. These questions are, often, the same ones your germophobic friend would obsess over, including the validity of the five-second rule as well as with how bacteria spreads with double dipping (a lot), sharing popcorn (very little), and beer pong (do you even need to ask).