Bottled water could be to blame for thousands of cases of food poisoning.
The findings have surprised health experts
A research team led by a scientist from the University of Wales in Cardiff has found that mineral water may be a previously unrecognised source of illness.
According to the findings it could account for thousands of cases of upset stomachs.
The soft drinks industry, however has disputed the findings.
There are 50,000 reported cases of food poisoning in Wales and England every year.
As many as 6,000 cases may be due to bottled water.
Scientists led my Dr Meirion Evans found bottled water could account for 12% of cases caused by the campylobacter bug - the biggest cause of food-borne infection in the western
Salad accounted for 21% and
It normally causes stomach pains and diarrhoea, but in rare cases can trigger serious and potentially fatal illness.
Contaminated water supplies, milk, and poultry are recognised risk factors for campylobacter.
But this new research suggests that bottled mineral water is also a potential hazard which could have wide public health implications.
The scientists, led by Dr Meirion Evans, from the University of Wales in
Cardiff, wrote in the American journal Emerging Infectious Diseases: "Eating
chicken is a well-established risk factor, but consuming salad and bottled water
"The association with salad may be explained by cross-contamination of food
within the home, but the possibility that natural mineral water is a risk factor
for campylobacter infection could have wide public health implications."
The British Soft Drinks Association, on the other hand, has dismissed the link.
In a statement, the organisation said the study did not reveal a connection between campylobacter infection and bottled water.
"It reveals a statistical association which is a different thing," the statement said.
"For example, the study also reveals a statistical association between campylobacter infection and walking for more than 15 minutes, but no-one is suggesting that walking causes food poisoning.
"For there to be a connection between campylobacter infection and bottled water, the campylobacter organism would have to be actually found in the water. It never has been.
"Natural mineral waters are drawn from protected sources that are free from contamination.
"Spring waters and table waters may be treated to ensure that they are not contaminated.
"Furthermore, all bottled waters are tested thoroughly for microbiological contamination and only released for consumption if those tests come up clear."
The UK bottled water industry is currently worth £700m and is set to double by 2005.
Brecon Carreg, the largest Welsh bottled water producer, said the summer heat wave had boosted their sales by 40% over this time last year.