E. coli and spinach: How to make safe choices

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E. coli and spinach: How to make safe choices

E. coli — A Mayo Clinic specialist answers questions about E. coli and produce safety.

Photo of William Marshall, M.D.William Marshall, M.D.

Fresh spinach has been given the all-clear by federal officials. But in the wake of a nationwide Escherichia coli (E. coli) outbreak, you might have lingering doubts about produce safety.

Here, William Marshall, M.D., an infectious disease specialist at Mayo Clinic, Rochester, Minn., answers questions about E. coli.

How does spinach become contaminated with E. coli?

E. coli refers to a group of bacteria normally found in the intestines of healthy humans and animals. Of the hundreds of types of E. coli, most are harmless. But a few strains of E. coli are responsible for serious food-borne infections — including E. coli O157:H7.

Spinach can become tainted with E. coli by exposure to contaminated water or animal or human waste. Cattle manure that contains E. coli O157:H7 — which can contaminate streams that flow through produce fields — is one possible concern.

Is it safe to eat fresh spinach again?

Yes. Spinach implicated in the fall 2006 E. coli outbreak was traced back to a specific California supplier. All affected spinach has been recalled. As long as you've discarded any fresh spinach or salad blends that may have been affected by the recall, it's safe to begin eating fresh spinach again.

It's important to remember that fresh spinach has been eaten for years. For the most part, the health benefits of eating leafy green vegetables far outweigh the risks.

What about other types of fresh produce?

Fresh spinach was the only type of produce associated with the fall 2006 E. coli outbreak. Lettuce, broccoli, carrots and other types of fresh produce were not affected by the outbreak.

Is organic spinach safer than conventionally grown spinach?

Organic foods are produced without conventional pesticides, antibiotics or growth hormones. Although organic foods haven't been proved safer or more nutritious than other foods, eating organic foods can limit your exposure to pesticides and other potential contaminants in food — but E. coli may remain a concern.

Remember, E. coli is caused by exposure to contaminated water or animal or human waste. Such exposure is possible whether a crop is grown organically or not.

What about homegrown spinach?

For some people, homegrown spinach is an appealing alternative to commercially grown spinach — but the same caveats about E. coli apply. If the spinach is exposed to contaminated water or animal or human waste, E. coli may be a concern.

I've read that simply washing fresh produce doesn't remove E. coli. Is that true?

Bacteria are sticky. Washing produce under running water won't necessarily get rid of E. coli — especially in leafy greens, which provide so many spots for microorganisms to attach themselves to. To kill the bacteria, you must thoroughly cook the produce.

But it's still important to wash all fresh produce under running water before eating, including produce that will be peeled before eating. Careful rinsing can remove dirt and reduce the amount of bacteria that may be clinging to the produce. Plain water is fine. There's no need to use soap or commercial cleaners to wash produce.

As an extra measure of caution, you may want to rinse pre-washed bagged produce before eating. Drying produce with a clean cloth towel or paper towel may help, too.

To avoid contaminating other foods and kitchen surfaces, wash your hands, utensils and kitchen surfaces with hot, soapy water before and after handling fresh produce.

After eating contaminated produce, how long might it take to get sick?

E. coli O157:H7 produces powerful toxins that can cause abdominal cramps and bloody diarrhea. Signs and symptoms of an E. coli infection usually develop within two to three days after exposure. It's possible to get sick up to one week later, however.

How long does an E. coli infection usually last?

Most healthy adults recover completely within a week, but some people — particularly young children and older adults — can develop a life-threatening form of kidney failure called hemolytic uremic syndrome (HUS).

When should I contact my doctor?

If you become ill after eating fresh produce, contact your doctor promptly. Your doctor may want to test a stool sample for the presence of E. coli bacteria. For most people, rest and plenty of fluids are the best treatment for an E. coli infection.

Is there a vaccine for E. coli?

There isn't a vaccine to offer protection from E. coli, nor are there any medications to help prevent infection. The best way to protect yourself from E. coli is to handle your food safely.

  • Wash your hands, utensils and food surfaces often.
  • Keep raw foods separate from ready to-eat foods.
  • Thoroughly cook ground beef to at least 160 F. (Hamburgers should be well-done.)
  • Wash fruits and vegetables under running water.
  • Avoid unpasteurized milk, juice and cider.

Also make sure that everyone in your family — including children — washes his or her hands after using the toilet or changing diapers and before eating.

Last Updated: 10/04/2006
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