Academic journal article Journal of Environmental Health

Drinking-Water Quality and Issues Associated with Water Vending Machines in the City of Los Angeles

Academic journal article Journal of Environmental Health

Drinking-Water Quality and Issues Associated with Water Vending Machines in the City of Los Angeles

Article excerpt


Many people concerned about the quality or contents of tap water buy bottled water, filtered tap water, or water from a water vending machine. Waterborne-disease outbreaks, such as the Cryptosporidium outbreak in Milwaukee, Wisconsin, have fueled public concern about tap water (FDA, 2001; McSwane, Oleckno, & Eils, 1994). Retail stores may sell filtered tap water or have a water vending machine inside or outside the store. The quality of water from water vending machines has been questioned, however. A University of Arizona study completed in 1996 found bacteria in one out of four machines tested, though none of the bacteria that were found cause dangerous infections (Rutz, 1996). More recently, the Los Angeles County Agricultural Commissioner/ Weights and Measures Department (LACAC) conducted the 1997-98 Water Vending Machine Pilot Study, testing 279 samples throughout the county. LACAC reported that 26 percent of the water from water vending machines had a heterotrophic plate count (HPC) of greater than 500 colony forming units per milliliter (CFUs/mL), averaging 1,306 CFUs/mL, with five sites positive for total coliform bacteria and one site positive for fecal coliform bacteria (Fiksdal & Shindy, 1998).

The California Department of Health Services (CDHS) Food and Drug Branch, with industry cooperation, subsequently conducted a study of 794 water vending machines in 37 counties (Glacier Water Services, Inc., 2001; Waddell, 1999). CDHS reported that 20 percent of the samples had an HPC of greater than 500 CFUs/mL (637 CFUs/mL was the average, excluding tour with over 10,000 CFUs/mL); 11 samples were positive for total coliforms and none for fecal coliforms (Lee, Terrazas, & Delacruz, 1999). CDHS concluded that additional regulatory, requirements for vended water were unnecessary, but that identified quality control areas deserved more attention. The identified areas were as follows:

* microbial growth in the tubing between the ultraviolet light and the dispensing spout,

* a need for better maintenance of the vending machines to ensure that sufficient minerals are removed from the source water, and

* a need for better maintenance of all required information labeling and the self-closing dispensing doors.

CDHS does not routinely inspect water vending machines, but requires licensing and third-party testing. It also will respond to a public complaint about a particular machine or store, according to CDHS representatives.

Both the LACAC study and the CDHS study detected microbial activity in vending machine water, which may indicate biofilm development. The organisms in the complex matrix of biofilm exude a protective coating, a slime that protects the biofilm from antibiotics, disinfectants, and toxins. Some heterotrophic bacteria form biofilms on any number of surfaces, including the human body. For example, Pseudomonas aeruginosa has been found as biofilm in the lungs of cystic fibrosis patients (Costerton, Stewart, & Greenberg, 1999). One study found an association between Pseudomonas spp. in dental water lines and the same species in the nasal flora of the dental patients (Penn, Sanders, & Sanders 1981). Another study found an association between Pseudomonas aeruginosa in wounds of dental patients suffering front cystic fibrosis and Pseudomonas aeruginosa in biofilms inside dental water lines (Martin, 1987). Pseudomonas aeruginosa, an opportunistic pathogen often associated with waterborne-disease transmission, has a relatively high resistance to disinfection (McFeters, 1990). Dental unit water lines and water vending machines do not have much in common other than that they both provide water; however, the studies cited above demonstrate the ease with which Pseudomonas spp. is transferred from dental unit water to the patient, and the susceptibility of an immunocompromised person to Pseudomonas aeruginosa, even with limited contact. …

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