How a Deadly Strain of E coli Bacteria Could Have Found its Way into Spinach
A food safety expert says it likely came from processing the produce right in the fields, a practice that's become much more common
By ALICE PARK
Friday, Sep. 15, 2006
When the Food and Drug Administration (FDA) issued a warning to consumers on Thursday about E coli contamination in bagged spinach, it didn't come as a surprise to Michael Doyle. So far, 50 people have fallen ill and one death has been connected to the dangerous E coli 0157:H7 bacterial infection, and the director of food safety at the University of Georgia says that outbreaks like this one will only continue if produce manufacturers don't change their practices.
E coli 0157 is a particularly nasty strain of the E coli that lives and thrives in our digestive tract. Animals such as cows tolerate 0157 far better than people, and often shed the bacteria in their feces. The bacteria can then infect crops such as lettuce, spinach, onions, or even apples when contaminated manure is used as fertilizer, or when contaminated water is used to irrigate fields. Most recently, E coli 0157 found in bagged salads packaged by Dole sickened over two dozen people in 2005.
These outbreaks, warns Doyle, are an inevitable byproduct of the way that many fruit and vegetable manufacturers have streamlined their production — and cut costs — by doing some of the processing of their ready-to-eat produce right in the fields, and not in the more controlled atmosphere of a factory. He sees it as a dangerous practice that could contribute to contamination." Two to three years ago, I was asked to go out and view what was going on in the fields when there was an outbreak associated with a fast food restaurant chain from their cut-up lettuce," he told TIME." Every company at the time was using the same concept to process head lettuce — they would core the lettuce in the field, remove the outside leaves, and put it in chlorinated water. The goal is to reduce costs, because you don't have to take the waste from the factory and bring it back to the field. The problem is, they are working out in the dirt. There are so many different ways that E coli can get into the food this way."
The FDA's director of Food Safety and Applied Nutrition, Dr. Robert Brackett, recognizes the riskiness of such processing in the field, and sent a warning letter to the California growers that had provided the contaminated lettuce in last year's outbreak, noting that" claims that 'we cannot take action until we know the cause' are unacceptable."
In response, Kathy Means, spokesperson for the Produce Marketing Association (PMA), which represents the fruit and vegetable growers industry, notes that processing for ready-to-eat products" is happening in a enclosed facility, not in the field. No one is putting produce in bags out there." Because produce can only become a source of E coli 157 infection by being contaminated from another source, PMA advocates good agricultural practices, which includes keeping tools and equipment used to cut produce clean and isolated from potential sources of E coli, as well as regulating how far away portable toilets provided for workers need to be placed from growing produce. One thing they can't control, however, is waste from birds and other infected wildlife that might contaminate fields. Fortunately, when outbreaks do occur, the Centers for Disease Control (CDC) in Atlanta is better equipped than ever to investigate clusters of disease cases and trace their cause. In this outbreak, the first call came into the CDC on Wednesday afternoon. An epidemiologist at the state health department in Wisconsin had been investigating almost 20 reports of E coli poisoning in a matter of days, and after some initial labwork and extensive interviews with the victims, all of whom had reported bloody diarrhea, the scientists there suspected that bagged sp> inach might be the culprit, and called Atlanta. Shortly after, Dr. Patricia Griffin, chief of enteric diseases at CDC says that the agency received a call from an epidemiologist in the state health department in Oregon. He had five cases, also traced to bagged spinach, and wondered if anyone else in the country had been reporting E coli illnesses. The information was added to CDC's database, and after comparing the lab work done in the two states, says Griffin, the CDC realized the cases could be traced to the same subtype of E coli, which suggested that the illnesses had a common cause — bagged spinach. After more investigation on Thursday to confirm the source, including trying to come up with the actual brand or brands responsible, the CDC decided on Thursday afternoon to issue its warning to consumers on bagged spinach." We're still very early in this investigation," she told TIME." New information in coming in constantly."
While it's still not clear exactly how the packaged spinach was contaminated, health officials suggest that no bagged spinach should be eaten raw. Cooking the leaves at 160 degrees F will kill the organisms, but washing, even in warm water, may not be enough to eliminate all of the bacteria that may have become embedded in the plant tissues when stalks or leaves are broken.
More on this outbreak: Dole and Natural Selections Spinach E. coli Outbreak