TORONTO — A commercial laboratory that tested several brands of bottled water from Ontario and Quebec found many contained high levels of one class of bacteria, but even the researchers say such bugs are unlikely to cause harm.
C-crest Laboratories of Montreal decided to test several brands of bottled water randomly purchased from different stores in the city. The project was sparked by an employee complaint of a bottled water product tasting foul and causing sickness.
The researchers found more than 70 per cent of 10 bottled water products — which they would not name — had heterotrophic bacteria levels that exceeded the limit recommended by the United States Pharmacopeia (USP).
Heterotrophic bacteria include those that consume organic matter. USP, a non—governmental body that sets widely recognized standards for medicines, food ingredients and dietary supplements, suggests this class of bacteria should not exceed 500 colony forming units (cfu) per millilitre of drinking water.
The Montreal lab, which specializes in pharmaceutical product testing, found bacterial counts in their samples that ranged from 100 to 80,000 cfu, said researcher Sonish Azam. In contrast, the average level for different tap water samples was 170 cfu/ml.
“Heterotrophic bacteria counts in some of the bottles were found to be in revolting figures of one hundred times more than the permitted limit,” said Azam, who took part in a webcast Tuesday following presentation of the study at the American Society of Microbiology meeting in San Diego.
“Bottled water is not expected to be free from microorganisms, but the cfu observed in this study is surprisingly very high,” she said. “Therefore, it is strongly recommended to establish a limit for the heterotrophic bacteria count as well as to identify the nature of microorganisms present in the bottled water.”
Still, she conceded that bacteria are unlikely to cause disease in humans and no disease-causing agents were found in the bottled water products tested.
Regulatory bodies such as Health Canada and the U.S. Food and Drug Administration have not set a limit for heterotrophic bacteria counts in bottled drinking water, and the World Health Organization years ago stopped recommending total bacterial counts, including heterotrophic plate count bacteria, or HPC.