Salads straight from the bag sure are handy and when the containers say "fresh," "pre-washed," and "thoroughly washed," you may think the greens are squeaky clean. But how clean are they?

Consumer Reports examined more than 200 packages to find out. The salad greens were bought in the New York metro area and covered 16 brands, including Dole, Earthbound Farm Organic, and Fresh Express.

The good news is lab tests did not find disease-causing bacteria like E. coli, listeria, or salmonella.

But they did detect other bacteria.

"Our tests found total coliforms and enterococcus -- bacteria that are indicators of poor sanitation and fecal contamination," Kim Kleman said.

"There are no federal standards for these organisms in salads, but there should be."

Of the 208 bags tested, there were relatively high levels of total coliforms in 39 per cent of the salads, and enterococcus in 23 per cent.

Most brands had at least one package with elevated levels. But even within the same brand, results varied widely.

"It didn't matter whether the salads came in a clamshell or a bag," Kleman said.

"But the ones with higher levels of bacteria tended to contain spinach, or be within five days of their use-by date."

Even rinsing the salads at home won't get rid of all the bacteria, though it will remove dirt. Your best bet is to buy the freshest produce you can. Consumer Reports found the cleanest greens were at least six days away from their best before date.

Stricter produce safety standards may be on the way.

The US senate is considering a bill to set standards for the types of bacteria that Consumer Reports found in its tests of bagged salad. And since that's where our bagged salad comes from -- we'll benefit as well.

With a report from CTV British Columbia's Chris Olsen