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PUBLISHED: 5:02 PM on Wednesday, May 10, 2006
Finding the source of E.coli in your veggies
Recent outbreaks of foodborne illness have resulted in 26 cases in three Midwestern states with 10 similar cases occurring in Minneapolis hospitals in three days. Public health investigators contacted people who were ill and interviewed them while they were still in the hospital. The purpose of the investigation was to determine any similarities in types of foods the patients had eaten.


Dr. Sonja Koukel
Dr. Steve Swanson of the Centers for Disease Control and the Minnesota department of public health considered the patients' symptoms and thought it might be an outbreak of E.coli 0157 bacteria. Typically, E.coli is associated with undercooked ground beef, but the victims hadn't eaten ground beef. The one food they all had in common was bagged salad. According to Dr.Swanson, what most people are not aware of is that next to ground beef, lettuce is the most commonly implicated food item for E.coli 0157 infections.

In the past five years, the Food and Drug Administration and the Centers for Disease Control and Prevention have noticed a marked increase in the number of E.coli outbreaks that were traced back to fresh produce. In beef, E.coli is usually killed by thorough cooking, but with lettuce there is no heating step so the person eating the contaminated produce is likely to get very sick.

So, how did the E.coli get into the lettuce?

To solve this perplexing mystery, state and federal health officials have launched a wide-ranging investigation. At the time of this writing, the government has no answer, only theories.

Some food scientists wonder if the practice of coring the lettuce right in the field creates an opportunity for E.coli to enter the plant. At the packing plant, the lettuce is chopped, sliced, mixed and washed. Experts fear that in this process, even a small amount of E.coli contamination can be spread around and end up in many bags of salad.

Finding the source of the problem is compounded by the fact that E.coli bacteria are everywhere in the environment. Illness from the bacteria has been caused by foods including undercooked ground beef, roast beef, raw milk, improperly processed cider, contaminated water, mayonnaise, cantaloupes, and vegetables grown in raw manure fertilizer.

The lettuce could have been contaminated by bird droppings, irrigation water contaminated with animal feces, or inadequate hand washing by plant workers.

E.coli invades the human intestine. Most people are sick from 4 to 10 days with severe abdominal cramps, diarrhea and sometimes bloody diarrhea. More serious cases can result in

kidney failure, seizures, strokes, and death, especially in persons at higher risk of foodborne illness such as children, the elderly, pregnant women, and those with weak immune systems.

While we wait for the scientists and experts to figure all this out, there are preventative steps consumers can take to safeguard themselves:

• Wash the salad before serving. Even though bag lettuce is pre-washed and is labeled ready to eat - Wash it again! Chemical rinses and other treatments for washing raw produce (usually called fruit and vegetable washes) are now sold in most grocery stores, however these can be costly. In the home, the best procedure is to wash fruits and vegetables with distilled or bottled water. This method is recommended because distilled or bottled water has been filtered and purified to remove contaminants.

If distilled or bottled water is not available, wash the produce for at least one minute under running tap water.

• Wash your hands. This cannot be stressed enough. Always thoroughly wash your hands with soap and water after handling raw meat and before you handle any other utensils or other food items.

• Clean food preparation surfaces frequently. Clean the counter top, cutting boards, and utensils with hot, soapy water after preparing each food item. Always clean any surface that has come in contact with raw meat, before any other item is placed on that surface.

• Avoid cross contamination by keeping vegetables separate from any raw meats.

• Refrigerate the bagged salad and keep it refrigerated until serving.

• Check the expiration date, or the "eat by" date, before serving. Even if the lettuce looks good, you should know that E.coli can grow quickly in deteriorating greens.

The best advice in reducing foodborne illness and outbreaks of E.coli is to be an informed consumer. Realize that there is always a risk and take the necessary action to minimize the risk. Free educational materials on foodborne illness and E.coli are available at the Cooperative Extension Service office.

Dr. Koukel is the Juneau District Agent for the Home Economics Programs of the UAF Cooperative Extension Service.


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