Public restrooms are widely considered the most bacteria-laden places around.

But how much truth does the conventional wisdom about public restrooms really hold? Over the years, various studies have found that they are not quite so bad, at least compared with other public areas.

One of the most extensive and revealing studies of the claim was published recently in The International Journal of Environmental Health Research. A team of scientists spent four years collecting nearly 1,100 samples at places like airports, restaurants, offices and bathrooms in four American cities. The scientists looked specifically for levels of bacteria as well as biological markers that indicated the presence of things like sweat, hemoglobin and urea.

The most frequently contaminated areas were playgrounds and day-care centers, with 46 percent showing high levels of contamination. Public restroom surfaces ranked far behind, at 25 percent, just ahead of public transportation handrails and armrests (in buses, for example) and shopping cart handles (about 21 percent each). Not far behind that were escalator handrails (19 percent), vending machine buttons (14 percent) and public phones (13 percent).

The study also found that in about 86 percent of cases, the contaminants on a surface were transferred to an individual's hands, and then, in 82 percent of cases, to personal belongings.

But other studies have produced reassuring findings. Most have found that the risk of illness from these sources is low, and that washing your hands with soap and water can reduce that risk by about 50 percent.

THE BOTTOM LINE: Public restrooms rank behind playgrounds and day-care facilities and just ahead of handrails in terms of contamination levels.