There may be more in that glass than soda and ice.

RODALE NEWS, EMMAUS, PA—When you think fountain soda, you may imagine a cool, refreshing drink. Or maybe a caffeine boost or sugar rush. Perhaps hiccups from the carbonation. But a new study published this month in the International Journal of Food Biology found that coliform bacteria, a type associated with fecal matter, is an unexpected ingredient in an alarming number of tested fountain drinks.

THE DETAILS: Study author Amy White, MS, assistant professor of biology at Virginia Western Community College, and colleagues tested 20 self-service beverage stations and 10 at which workers pour drinks for customers, to come up with a total of 90 fountain-beverage samples. The tests including sugared and diet sodas, as well as water from the fountain. While none of the ice, which was also tested, exceeded U.S. drinking-water standards, 48 percent of the fountain drinks tested contained coliform bacteria, with 20 percent containing amounts higher than what the Environmental Protection Agency (EPA) allows in drinking water. More than 11 percent of the analyzed drinks contained E. coli bacteria, a type of coliform that the EPA does not allow in any amount in drinking water. Researchers also detected other microorganisms that can make people sick, particularly people with compromised immune systems. Most of the bacteria was resistant to at least one of 11 antibiotics tested. "In our study, we tested sodas and water from bottles as controls, and none contained any microbial growth," White adds.

Read on to find out how to avoid germy soda.