Photo by V. Miller
July 26, 2006
A Germicidal Light
A Germicidal Light Zaps the Bugs that Bite
Taylor Jones, 12, Maryville, Tenn.
Finalist, Discovery Channel Young Scientist Challenge, 2005
Project background: Last year, Taylor's grandmother became sick. Her doctor suggested that her illness might have been caused by bacteria on soda cans that she had purchased from a vending machine. Taylor hypothesized that snacks and sodas exposed to a germicidal, or germ-killing, light would have fewer bacteria on their surfaces than items that came straight from the vending machine.
Tactics and results: Taylor collected 13 snacks and drinks from vending machines. He took them to a laboratory at the University of Tennessee. He swabbed each package and incubated the swabs. He recorded the number of bacterial colonies for a baseline score. Then, he exposed the packages to germicidal light for 15, 30, or 60 minutes, reswabbed them, and grew more colonies.
All the untreated packages tested positive for bacteria. After being exposed to a germicidal light for 60 minutes, all the bacteria were killed. Taylor concluded that exposure to germicidal light does kill bacteria on items purchased from vending machines.
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