Charles Gerba, professor of microbiology at the University of Arizona, is a bacteria bigwig. In the 1970s, he warned us about toilet plumes -- clouds of contaminated water that fill our bathrooms every time we flush stuff down the loo. A few years later, he revealed the microbial landmines lurking in our kitchens, on sponges, cutting boards, countertops and sinks. And then he opened our eyes to the invisible, disease-carrying world found on TV remote controls in hotel rooms.
More recently, Gerba turned his attention to the workplace. In research sponsored by consumer product company Kimberly-Clark Professional and conducted as part of The Healthy Workplace Project, the microbiologist and his associates swabbed close to 5,000 surfaces in several office buildings with at least 3,000 employees. Back in the lab, they tested the swabs for adenosine triphosphate, or ATP, a chemical found in all living cells and therefore an indicator that bacteria, yeast and mold were likely present on the item tested. An ATP reading of 100 indicated a dirty object; a reading of 300 or higher indicated a filthy object [source: Castillo].
Of the water fountain buttons tested by the researchers, 23 percent earned ATP readings of 300 or more. A little more than half scored 100 [source: Castillo]. Either way, it's a sure sign that the water cooler is a great place to catch some gossip -- and your next cold. Just use your shirtsleeve and remember to wash the shirt later.