Bacterial Transfer by Blowing Out Birthday Cake Candles

Knowledge accretes in bursts and puffs, as in this study:

Bacterial Transfer by Blowing Out Birthday Cake Candles,” poster presented at Clemson University’s 5th Annual Focus on Creative Inquiry Poster Forum April 12, 2010.

Mentors: Paul Dawson and Inyee Han, Department of Food Science & Human Nutrition

Students: Danielle Lynn, Jenevieve Lackey, Johnson Baker, Sutton Fainschwartz, Aaron Pietzyk

“Bacteria are an unavoidable element of life, present in the environment and other living organisms. Whether benign or pathogenic, it is important to understand how bacteria is transferred and become familiar with measures for avoiding contamination. As such, this research project focused on the potential spread of bacteria when blowing out candles on a birthday cake. Our first procedure involved blowing on Petri dishes containing nutrient agar. A second procedure consisted of blowing on lit candles placed over a layer of icing. In a third procedure, we tested whether salivating before blowing out the candles over icing would affect the outcome. To simulate a realistic party atmosphere, this procedure included consuming a slice of fresh pizza prior to blowing on the candles. We determined that a higher level of bacteria was transferred with this procedure than the previous testing. These results led us to conclude that bacteria expelled from the mouth can, in fact, contaminate birthday cakes and other potential food samples.”