October 9, 2023 – A small study in California found that 4 out of 10 samples from soda fountains contained potentially dangerous contaminants. The study also raised concerns concerning the safety of water sold in stores by refilling large take-out jugs.
The research by Loma Linda University microbiologists was recently published within the journal Water supply.
For the study, researchers collected 72 samples from three forms of water sources: soda fountains, water vending machines, and tap water faucets within the stores where the water vending machines were positioned. Water vending machines are those typically present in grocery stores that fill large jugs that customers then take home.
All samples for the study were collected from the desert region of Southern California called the Eastern Coachella Valley.
The fast food restaurants where the samples were collected were unaware of the study and the researchers purchased a meal and a drink on the locations where the samples were collected.
They found bacteria called total coliform bacteria in:
- 41% of beverage fountain samples
- 20% of water vending machine samples
- 50% of the tap samples got here from the stores where the water vending machines were positioned
- 88% of the swab samples got here from the inside the taps of water dispensers and taps
According to the USA Environmental Protection Agency“The presence of coliform bacteria in tap water suggests that there could be a problem with existing equipment or treatment systems, contamination of the source water, or a break in the distribution system that could cause it.” E.coli Contamination.”
E.coli According to the EPA, when water is contaminated, fecal matter is typically present. But samples that are positive for total coliform bacteria do not necessarily mean that the water is contaminated with it E.coliand the EPA recommends further testing of water positive for total coliforms.
Loma Linda researchers also tested the water directly from the local water authority and found that the samples were all within safety limits. They concluded that the sources of contamination in their other tests were pipes and equipment.
“Although the Coachella Water District has provided clean water, we can conclude from the results posted on its website and the analysis of the water tank we analyzed [tap water] Spigots, fittings or other plumbing fixtures are likely contaminated with biofilms,” the authors write.
Biofilms are a mucous layer of microorganisms that form on surfaces that come into contact with water.
A water research expert at Michigan State University who was not involved in the study said the results show more monitoring is needed.
“It's concerning that they found these pathogens,” said Dr. Joan Rose, a microbiologist at Michigan State USA today. “It is clearly an indicator that we need to do more research like this. We just don’t know how big the threat is.”
A representative from the National Restaurant Association told the news outlet that soda fountains have to be cleaned frequently under federal guidelines, noting that there are known problems with tap water quality locally where the study was conducted.
“We encourage restaurant operators to work with their suppliers to learn and understand how best to clean and disinfect all food contact surfaces, in accordance with the Food Code and applicable local laws, regulations and guidelines said Patrick Guzzle, MA, vice president of food science at the National Restaurant Association.
The authors emphasized that their results raise concerns.
“The presence of pathogenic microorganisms in drinking water represents a serious public health problem and cannot be overemphasized,” they wrote.