Soda fountain machines harbor fecal bacteria, study finds

Posted on Jan 11, 2010 in Uncategorized

BY Rosemary Black


Is it possible your self-serve soda could be flush with yucky bacteria?

You may want to consider ordering a bottled beverage rather than filling your own glass at a fast food restaurant: A study shows that drinks from soda foundation machines in restaurants and fast food establishments might actually harbor fecal bacteria, according to a study reported by

Nearly half the beverages coming out of the machines were contaminated with coliform bacteria, which indicates possible fecal contamination, according to the small study, which sampled 30 soda machines in Roanoke Valley in Virginia. The machines squirted out coliform bacteria along with the beverages.

“We can’t have that in our drinking supply,” said Renee D. Godard, Hollins University biology professor and co-author of the paper, published in the January print issue of the International Journal of Food Microbiology. “But they’re coming out of these soda fountain machines.”

Some 48 percent of the beverages had coliform bacteria, according to Godard. But only 20 percent of the drinks in the sample contained coliform bacteria that actually exceeded the U.S. Environmental Protection Agency’s limits set for drinking water. Ice and tap water from the machines didn’t test positive for any bacteria.

So far, the source of the bacteria is unknown. The restaurant managers Godard spoke with said they cleaned the nozzles every day, and not many people at the restaurants were seen touching the nozzles of the machines. Yet just one manager said he regularly rinsed the plastic tubing inside the machines.

It may just take one nozzle contamination for the bacteria to start growing in the tubing and the machine, Godard speculated.

“Our best guess is that they’re actually establishing themselves on the lining of the plastic tubing,” she told “The reason we say that is in other areas, such as hospitals, it is known that bacteria can establish themselves on plastic tubing for machines.”

In a statement to, the Coca-Cola Company said it was unaware of any illnesses related to its fountain-dispensed beverages, and that it “has been serving fountain beverages for more than 120 years.”

University of Arizona microbiologist Charles Gerba told that coliform bacteria have been seen in drinking water dispensing machines where the customers fill up jugs of water. “You see it anytime you have something where people can touch the dispenser,” he said.

No recent outbreaks of gastrointestinal illness have been reported in Roanoke Valley or other parts of the country. But the presence of the bacteria is still a worry. Since a less dangerous form of E.coli was found in the soda machines, it’s possible that the machines could host more virulent strains of E.coli. And if the machines can harbor bacteria, they may also harbor viruses.

“That’s what I would worry about because you get one of these tips contaminated and you contaminate a lot of soda,” said Gerba. “It suggests it’s a route for transmitting something like Norovirus (which causes gastrointestinal illness) because fecal contamination is occurring.”

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