Researchers from Clemson University, US, examined the potential spread of bacteria when someone blows out candles on a cake.
“The tradition of blowing out birthday candles has different theories as to its origin. Some theorise the practice began in Ancient Greece, and was related to bringing cakes with lit candles to the temple of the goddess of the hunt, Artemis,” the researchers said in the study, which has been published in the ‘Journal of Food Research’. “Other ancient cultures believed that the smoke from candles carried their wishes and prayers to the gods,” they wrote. According to the researchers, bioaerosols in human breath may be a source of bacteria transferred to cake surfaces.
To test aerosol transfer to cake, icing was spread evenly over foil and birthdaycandles were placed through the foil into a base. After consuming a pizza, volunteers were asked to extinguish the candles by blowing. The team then recovered icing samples and determined the level of bacterial contamination.