The Co-op Food Stores

added 06/23/08

by Rosemary Fifield, Director, Education and Member Services

For years, consumers were aware of dangerous bacteria associated with raw poultry, eggs, and meat. We knew that consumption of undercooked poultry or eggs could result in foodborne illness from Salmonella and that improperly cooked ground beef could put us at risk from dangerous forms of E. coli. We recognized the possibility of cross-contaminating ready-to-eat foods, like salads and raw vegetables, if we weren’t careful when handling raw poultry and meats, and so we washed our hands and utensils frequently and kept separate cutting boards for each type of food.

Then E. coli O157:H7 and various Salmonella species began showing up on produce itself. Salmonella was found on cantaloupes in 2002 and again in 2008. Packaged spinach and other leafy greens were recalled in 2006 because of the presence of E. coli. The recent warning about tomatoes with Salmonella is just one of several in the past ten years. Obviously, these pathogens are no longer confined to animal products.

So how did E. coli and Salmonella make the transition from meat to freshly harvested produce?

In the Field
Three main sources have been identified as the culprits: improperly composted manure, contaminated water supplies, and wild animals in the growing fields.

Livestock animals—cows, pigs, sheep, and chickens—can carry pathogenic bacteria in their intestines while showing no symptoms of their own. This often occurs when large numbers of animals are confined in close quarters such as feedlots or industrial-sized barns. Infected animals shed the bacteria in their waste, which may be composted, kept in waste lagoons, or spread on nearby fields. Proper composting will generate heat sufficient to kill the majority of pathogens. Raw manure, if used on food crops that will be harvested four months or less from application, can spread dangerous bacteria.

Runoff from pastures, feedlots, or improperly maintained waste lagoons has the potential to contaminate water supplies that farmers use for irrigation or washing their produce. Infected farm workers without proper toilet facilities in the fields have also been known to taint the water in irrigation ditches and streams.

Wild animals can carry the same intestinal bacteria as domesticated species. They spread the bacteria onto crops through their own droppings or by tracking in fecal material from infected livestock nearby. Wild boars with cow manure on their hooves are believed to have carried E. coli into the California spinach fields in 2006 when they broke through the fence to eat the spinach.

In the Processing
Large-scale production and distribution practices increase the impact of produce contamination when it does occur. Centralized packing and distribution plants allow commingling of clean produce with tainted before shipping it nationwide. Increased handling and travel time provides greater opportunity for bacteria to be introduced and to grow to dangerous numbers.

Widespread distribution also means that any resulting foodborne illnesses may be widely separated geographically, keeping authorities from recognizing an outbreak as quickly as they might if the cases were in one area. Tainted products may remain on the shelves for a longer period of time before the source is identified and a recall is initiated. The recent recall of tomatoes because of Salmonella began in early June; the first cases of illness were reported on April 10.

Assessing the Safety of Local
Tomatoes grown in New Hampshire and Vermont were never implicated in
the most recent tomato recall. However, the safety of local produce—even
produce grown in home gardens—should not be taken for granted.

Fortunately, if a grower is local, we have the opportunity to question that grower and possibly even see for ourselves how safely our food is being
produced and handled. So what should we look for?

• Livestock, including poultry, and their manure should be physically separated from food-growing areas.
• The droppings of pets and wild animals also contain a wide range of bacteria. Therefore, green yard waste should be properly composted, just like manure, before being put on a garden.
• Safe water should be used at all stages of production and harvesting.
• Those handling the produce should have appropriate toilet facilities and practice proper hygiene.
• Produce that requires refrigeration should be kept cold.

It’s in Your Hands
We have no good reason to fear the safety of produce as long as we use good sense when purchasing, handling, and cooking it:

• Purchase from a grower or retailer whom you trust.
• Choose fruits and vegetables without damage or obvious spoilage.
• Thoroughly wash all produce before eating or preparing it—even that which you grow yourself.
• Avoid cross-contamination, even among produce types. Always wash cutting boards, utensils, dishes, and countertops with hot water and soap when switching between types of foods.
• Refrigerate foods properly.
• When in doubt, throw it out.

What Do You Think?

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