Reprinted from: Tufts University Diet & Nutrition Letter
Vol.10, No.6, August 1992
The number of gallons of water flowing through water coolers has nearly doubled in the last few years, rising from some 270 million in 1985 to more than 460 million last year. Part of the increase, not just in offices but also in homes, schools, and hospitals, is no doubt due to consumers’ concerns about the safety of tap water. But, ironically, many coolers may be harboring unhealthful high levels of bacteria that can cause nausea and diarrhea in some people.
When scientists checked the bacterial count of water from 10 water coolers on the campus of Boston’s Northeastern University, they found that in each case the count reached at least 2,000 potentially harmful organisms for every thousandth of a liter of water, or four times the 500-organism limit the government recommends. In some coolers, particularly those that were used frequently, counts exceeded one million – or 2,000 times the government’s recommended ceiling.
The problem, say researchers, is not, that water delivered fresh in those large, see-through containers has high levels of organisms; water drawn directly from bottles (rather than dispensed through coolers) consistently falls well below the government’s recommended bacteria limit. Instead, it appears that organisms from each new bottle of water adhere to a cooler’s reservoir – the “well” in which the bottle sits – and also to its hot and cold water spigots, accumulating over time and thereby boosting the bacterial count of any water that passes through those areas on the way to a cup or glass.
Although healthy people are unlikely to become ill drinking such water, some of the bacteria are capable of causing the vomiting and diarrhea characteristic of an illness known as gastroenteritis.