Nov. 4, 2004 -- Choosing bottled mineral water over tap may not offer more protection against potentially hazardous bacteria, according to new research.
Dutch researchers sampled bottled mineral water from 16 countries, not including the U.S., and found about 40% of the samples showed evidence of contamination with either bacteria or fungi. In laboratory cultures, bacteria grew from 21 of the 68 samples.
Researchers say the high levels of bacterial contamination in commercially bottled mineral water may pose a health threat to certain people, such as children, the elderly, and those with weakened immune systems such as people with cancer, kidney failure requiring dialysis, diabetes, or AIDS.
The findings were presented this week at the Interscience Conference on Antimicrobial Agents and Chemotherapy in Washington, D.C.
Bottled Mineral Water May Not Be Safer to Drink
Researchers say people with weakened immune systems who are hospitalized are often given bottled mineral water under the assumption that it is not contaminated and therefore safer to drink than tap water.
But the results show that there is still a risk of infection from common illness-causing bacteria, such as legionella, from bottled mineral water. Infection with legionella bacteria can lead to a serious, pneumonia-like condition called Legionnaires' disease.
In their study, researcher Rocus Klont, of the University Medical Center Nijmegen in the Netherlands, and colleagues analyzed bottled water from nine European countries and seven others, including Canada, Australia, and Mexico.
They found all of the bottles appeared to have been properly sealed, which eliminated the possibility of contamination after bottling.
Laboratory tests showed 37% of the samples had evidence for contamination with bacteria, including legionella, and 4% had evidence of fungal contamination.