In the latest analysis of packaged leafy greens, Consumer Reports found that nearly 40 percent of samples tested contained bacteria consistent with poor sanitation and fecal contamination.

bagged-salad-featured.jpgLeafy greens have been under particular scrutiny since late 2009, when the Center for Science in the Public interest put them atop the 10 most dangerous foods regulated by the FDA list. According to the Center for Disease Control and Prevention (CDC), leafy greens have caused 363 food-borne illness outbreaks in more than 13,500 reported cases since 1990.

“You might think that ‘prewashed’ and ‘triple-washed’ salad greens sold in clamshells or bags are squeaky clean,” Consumer Reports said, “but our recent tests found much room for improvement.”

In a sample of 208 containers representing 16 brands, all well within their use-by dates, Consumer Reports found a common presence of bacteria used to gauge pathogen contamination–in some cases at very high levels. The tests were conducted at an outside lab with financial support from the Pew Health Group.

Consumer Reports tested for total coliforms and other bacteria, including enterococcus, that are reliable indicators of fecal contamination and poor sanitation. While there are no existing federal standards for indicator bacteria in leafy greens, there are standards for these bacteria in milk, beef, and drinking water.

Industry consultants suggest that an unacceptable level in leafy greens would be anything more than 10,000 colony forming units per gram (CFU/g). Consumer Reports found that 39 percent of samples exceeded this level for total coliform, and 23 percent for enterococcus. Packages that were closer to their use-by date or had spinach in them contained higher levels of bacteria.

“Although these ‘indicator’ bacteria generally do not make healthy people sick, the tests show not enough is being done to assure the safety or cleanliness of leafy greens,” said Dr. Michael Hansen, senior scientist at Consumers Union, nonprofit publisher of Consumer Reports. “Levels of bacteria varied widely, even among different samples of the same brand. More research and effort is needed within the industry to better protect the public.”

The study, which is being released in the March 2010 issue of Consumer Reports, is accompanied by a report urging the United States Senate to pass S. 510, a bill that would reform food safety standards in the United States.

“Consumers Union supports Senate Bill 510, the Food Safety Modernization Act, that would, among other things, require the Food and Drug Administration to set stronger produce safety standards,” the statement said. “Those should include performance standards for indicators of fecal contamination, such as generic E. coli and enterococcus.”

In the meantime, Consumers Union has several suggestions for minimizing the risk of leafy greens:

  • Buy packages as far from their use-by date as you can find
  • Even if the bag says “prewashed” or “triple-washed,” wash the greens yourself. Rinsing won’t remove all bacteria but may remove residual soil.
  • Prevent cross contamination by keeping greens away from raw meat.