Packaged Salad Can Contain High Levels of Bacteria



Consumer Reports’ latest tests of packaged leafy greens found bacteria that are common indicators of poor sanitation and fecal contamination, in some cases, at rather high levels. The story appears in the March 2010 issue of Consumer Reports and is also available free online. Consumers Union today also issued a report [PDF] urging the U.S. Food and Drug Administration (FDA) to set safety standards for greens. FDA food safety legislation pending in the Senate, and passed last summer by the House of Representatives, would require the FDA to create just such safety standards.

The tests, which were conducted with financial support from the Pew Health Group, assessed for several types of bacteria, including total coliforms and Enterococcus—“indicator organisms” found in the human digestive tract and in the ambient environment that can signal inadequate sanitation and the potential for the presence of disease-causing organisms. While there are no existing federal standards for indicator bacteria in salad greens, there are standards for these bacteria in milk, beef, and drinking water. Several industry consultants suggest that an unacceptable level in leafy greens would be 10,000 or more 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. The tests did not find E. coli O157:H7, Listeria monocytogenes or Salmonella—sometimes deadly pathogens which can be found in greens, although it was not expected given the small sample size. According to Consumers Union, the goal was to investigate other markers of poor sanitation that should be used in the food safety management of produce.

“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. In the meantime, consumers should buy packages of greens that are as far from the use-by date as possible.”

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For its latest analysis, Consumer Reports had an outside lab test 208 containers of 16 brands of salad greens, sold in plastic clamshells or bags, bought last summer from stores in Connecticut, New Jersey, and New York. Among the findings:

  • 39 percent of samples exceeded 10,000 CFUs (or another similar measure) per gram for total coliforms and 23 percent for Enterococcus, the levels industry consultants deemed unacceptable.
  • 2 percent of samples exceeded French and 5 percent Brazilian standards for fecal coliform bacteria.
  • Many packages containing spinach, and packages which were one to five days from their use-by date, had higher bacterial levels. Packages six to eight days from their use-by date generally fared better.
  • Whether the greens came in a clamshell or bag, included “baby” greens, or were organic made no difference in bacteria levels.
  • Brands for which there were more than four samples, including national brands Dole, Earthbound Farm Organic, and Fresh Express, plus regional and store brands, had at least one package with relatively high levels of total coliforms or Enterococcus.

CU is calling on the Senate to pass pending FDA food safety reform legislation that requires the agency to set performance standards as well as develop safety standards for the growing or processing of fresh produce. It’s also asking that FDA formally declare certain pathogenic bacteria—such as E. coli O157:H7, Salmonella, and Listeria—be considered adulterants when found in salad greens.

Until packaged salad becomes cleaner, consumers’ best line of defense involves following these procedures in stores and kitchens:

  • Buy packages far from their use-by date.
  • Wash the greens even if the packages say “prewashed” or “triplewashed.” Rinsing won’t remove all bacteria but may remove residual soil.
  • Prevent cross contamination of greens by keeping them away from raw meat and poultry.

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View Comments (12)

  1. Tuesday, February 2nd, 2010
    Why buy bagged salads at all? Are whole-head lettuces any safer? I would assume so, especially if you can get them locally.

    I also read a great tip on a blog the other day: Do grocery day kitchen prep. So, if you buy a head or two of lettuce, wash it up and chop/tear it and put it in your own plastic zip back or a bowl covered by a damp paper towel. Instant salad! You'll also probably use it faster that way, though it will go bad more quickly.
  2. Kimberley Hart
    Tuesday, February 2nd, 2010
    The sustainable farming community does not support his bill. While it would make major improvements in the federal regulatory regime related to food-borne illness from pathogens,by doing so it would erect significant barriers to better food and nutrition and improved public health by making costly requirements of small-scale farmers. Fred Hoefner at NSAC says, "It is not good policy to stick small and mid-sized family farms with large compliance costs to comply with industrial regulations," said Hoefner. "We support training and technical assistance to help farmers craft scale-appropriate on-farm food safety plans, a key element missing from the bill."

    For more information you can visit the National Sustainable Agriculture Information Service at http://attra.ncat.org/food_safety.html

    The sustainable community has been supporting the addition of Growing Safe Food Act (S. 2758 ) which is designed to provide food safety training, education, extension, outreach, and technical assistance and create an information clearinghouse for farms, with a special emphasis on small and medium-sized farms and small-scale processors.
  3. Andrew
    Tuesday, February 2nd, 2010
    If Goldman Sachs, Bank of America, and JP Morgan were all lining up in
    support of the government's plan for "financial reform," we'd all be a
    little suspicious, right?

    So isn't it also a little suspicious that the corporations lining up
    in support of "food safety reform" include Dole, Chiquita, Monsanto,
    McDonald's, Kraft, PepsiCo, ConAgra, and many others?

    I hope that everyone reading this is not so desperate for "food
    safety" that they will accept anything by that name. Giving a stinker
    of a bill a good title does not make it stink any less (see the
    PATRIOT Act). Check out the Cornucopia Institute for some
    ideas on how to make food safety safer
    .

    As you can see here, industry lobbyists like the Grocery Manufacturers Association, the United Fresh Produce Association, and the National Restaurant Association, among others, have all
    thrown their support to the existing bill.
  4. Tuesday, February 2nd, 2010
    HooRAY for Kimberly! Go get 'em

    I am all for food safety. However, my distrust for the USDA runs deep...even deeper for politicians making policy laws.

    The USDA has shown itself to being too often on the side of "Big AG". In personal experience, The USDA inspectors have always made it harder on us when we process our beef. They create paperwork and delay on a consistent basis while "rubber stamping" the larger producers. AND the inspector always moves the feedlot guys to the head of the line with just a perfunctionary inspection of a large number of animals. My 2-3 animals have to wait, sometimes up to 10 days (which creates stress and weight loss), and then he inspects EACH one....ugh!

    I know what it costs me in both time and money, but I cannot fathom what the "salad rules" will do to the average truck farm.
  5. Tuesday, February 2nd, 2010
    Has anyone gotten Monsanto's take on this? Based on their demonstrated consumer safety record, maybe we should get their opinion.(?)
  6. Mark Elliston
    Tuesday, February 2nd, 2010
    product to wash with, available at trader joes, I'm going to try it.
    http://www.youtube.com/watch?v=441KnMW4jqc
  7. Andrew
    Tuesday, February 2nd, 2010
    Smokey:

    I do not think that the food safety bills constitute an elaborate Monsanto conspiracy, and I wish people would stop saying that it is. They're overshadowing the many legitimate reasons to fear the bills.

    With that said, Monsanto is an important member of an agribusiness lobby group, the United Fresh Produce Association, which has by its own admissionworked closely with Congress on writing the food safety bills, one that has passed the House, and one that will come up in the Senate very soon. If you're concerned about the language of the bills, please let your Senator know!
  8. Terri
    Wednesday, February 3rd, 2010
    I'm sorry there wasn't more exploration of the source of the contamination in this story.

    Is it possible that the contamination is coming from produce grown in soil amended with biosolids/sludge from municipal sewage plants?
  9. Wednesday, February 3rd, 2010
    Consumers Best line of defense should read:
    -Grow the greens yourself, if you can, and pick fresh for your meal. Wash it first.
    -If you don't grow them, buy leafy greens in fresh bunches or whole heads direct from a farmer that you know. Wash those greens.
    -Support growers who support biodiversity and healthy, microbially-rich soils that naturally suppress pathogenic bacteria. Sterilized farming only supports the opposite (kill off the good & watch the bad run rampant)
    -Don't support any one-size-fits-all approach by the FDA nor USDA or it will eliminate small and mid-size producers or force them to stop growing leafy greens.
    -Realize that the illness and death caused by food-borne pathogens is considerably less than getting struck by lightening and therefore does not warrant the overly-regulated hysteria that is occurring right now.