Contaminated water found in soda fountains, water vending machines in east valley

A new study from Loma Linda University researchers found evidence of microbial contamination in fast-food soda fountains and water vending machines in eastern Coachella Valley cities.

A total of 72 samples were collected for the study. Results indicated that 20% of water vending machines, 88% of swab samples, 41% of soda fountains and 50% of tap water samples had total coliforms, an indicator of other pathogens in drinking water. And molecular analysis found the presence of genetic materials of six selected microorganisms, such as Salmonella, E. coli and Pseudomonas aeruginosa.

Many samples had microbial contamination above the limits set by the United States Environmental Protection Agency.

"Waterborne pathogens and their related diseases are a major public health concern worldwide," the authors wrote in their study. "The presence of pathogenic microorganisms in drinking water is a serious public health concern and cannot be overemphasized."

While waterborne outbreaks have declined in the last two decades, the authors state that waterborne microbial agents, such as Salmonella typhimurium, Vibrio cholerae, Legionella, E. coli O157:H7, and Pseudomonas, have been known to cause acute gastrointestinal illnesses, acute respiratory illnesses, hepatitis and death.

The rural and unincorporated communities of Thermal, Oasis, Mecca and North Shore in the eastern Coachella Valley have faced significant issues with water containing arsenic levels above federal legal limits in recent years. As a result, researchers conducted the study to assess the quality of drinking water from water vending machines and soda fountains in the area and to compare them to tap water collected in the community.

The study, "Microbial contamination analysis of drinking water from bulk dispensers and fast-food restaurants in the Eastern Coachella Valley, California," was conducted by Thomas Dama Hile, Stephen G. Dunbar and Ryan G. Sinclair. It was published in Water Supply, the International Water Association’s peer-reviewed journal.

This is the first study in the eastern Coachella Valley to assess the water quality from soda fountains, water vending machines, swabs and tap water, according to researchers.

Researchers sterilized one-liter glass bottles for water vending machines and half-liter metal water bottles for soda fountains prior to sampling. In the field, they collected two liters of water samples from each water vending machine, and swabbed the interior surface of spigots. They also collected a tap water sample from the same building. Drinking water from soda fountains was collected from the water spigot of a soda dispenser in a fast-food restaurant, or by requesting a water sample from a staff member.

Additional results from the study show that 72% of water vending machines, 25% of soda fountains and 41% of tap water samples had water temperatures ideal for the formation and growth of biofilms, an assemblage of surface-associated microbial cells that can harbor pathogenic microorganisms and pose threats to health and public safety.

The study authors believe biofilm formation in tap water distribution systems is likely the main source of contamination.

"Since water vending machines and soda fountains are connected to tap water systems, biofilms likely form overtime in the water distribution systems, which are mainly made of plastic piping, and are ideal for biofilm growth. The quality of filtration systems used for water vending machines and soda fountains appears to be insufficient to prevent consumers from drinking contaminated water," they wrote. "In this study, nozzle swabs demonstrated elevated bacterial contamination, supporting the idea that their location and structure are ideal for biofilm formation and summer drinking water contamination."

Researchers recommend "regular flushing and cleaning of water dispensers and the use of nanoparticle coated tubes inside water dispensers to control the growth of biofilms in water dispensers."

Ema Sasic covers entertainment and health in the Coachella Valley. Reach her at ema.sasic@desertsun.com or on Twitter @ema_sasic.

This article originally appeared on Palm Springs Desert Sun: Contaminated water found in soda fountains in east Coachella Valley