It’s only getting worse. Now, researchers in Canada are worried about the "revolting" levels of bacteria they found in certain popular Canadian bottled water brands. The scientists at Montreal's C-crest Laboratories said they expected some micro-organisms in the water, but the unnamed brands studied have a "surprisingly high" level of bacteria of the heterotrophic variety—bacteria that depends on an organic source of carbon to survive.
Even though they didn't find any serious pathogens, more than 70 percent of the well-known brands actually failed the standards for heterotrophic bacteria set by the NGO United States Pharmacopeia. According to them, bacteria per millilitre in drinking water should not exceed 500 colony forming units (cfu) - and compared to the sampled tap water average of 170 cfu per millilitre, some of the brands tested had a whopping 70,000 cfu per millilitre.
According to [study researcher Sonish] Azam, Health Canada hasn't set an allowable limit for heterotrophic bacteria in bottled water, and neither has the U.S. Food and Drug Administration.
Though Azam said the bacteria levels in the water are not likely high enough to cause disease, she warned that infants, pregnant women, the elderly, and those with weak immune systems who drank it could be at risk.