70 percent of Canada's bottled water has bacteria

More than 70 percent of bottled water samples in Canada were found swarming with bacteria, research has revealed.

The amount of bacteria found in the water exceeded the recommended norms specified by US Pharmacopeia (USP), a non-governmental authority that sets standards for medicines and food.

"Despite having the cleanest tap water, a large number of urban Canadians are switching to bottled water for their daily hydration requirements," says study author Sonish Azam, from C-CREST Laboratories.

C-CREST is a GMP (Good Manufacturing Practice) accredited lab in Canada specialising in pharmaceutical product testing and regulatory affairs.

"Unsurprisingly, the consumer assumes that since bottled water carries a price tag, it is purer and safer than most tap water," adds Azam.

Regulatory bodies such as Food and Drug Administration (FDA), Environmental Protection Agency (EPA) and Health Canada have not set a limit for the heterotrophic bacteria counts in bottled drinking water.

Heterotrophic bacteria are those that require an organic carbon source for growth, that is they derive energy and carbon from organic compounds.

Azam and her colleagues Ali Khamessan and Massimo Marino randomly purchased several brands of bottled water from a local marketplace and subjected them to microbiological analysis.

They discovered more than 70 percent of famous brands tested did not meet the USP specifications for drinking water.

"Heterotrophic bacteria counts in some of the bottles were found to be in revolting figures of 100 times more than the permitted limit," says Azam. In comparison the average microbial count for different tap water samples was 170 cfu/mL.

Azam stresses that these bacteria most likely do not cause disease and they have not confirmed the presence of disease-causing bacteria.

But the high levels of bacteria in bottled water could pose a risk for vulnerable populations such as pregnant women, infants, immunocompromised patients and the elderly.

The findings were presented at the 110th general meeting of the American Society for Microbiology in San Diego.