Raw Sprouts: Nutritious and Dangerous

SproutsOnce again, Shelf Life Advice wants to remind you that raw sprouts can be a risky food. They're often used to decorate summer sandwiches and they're also often contaminated with bacteria that cause food-borne illness.  Let's start with some reasons why sprouts are so susceptible to pathogens. Then we'll provide some suggestions for how to avoid them.

 Sprouts have the potential to be contaminated with Listeria monocytogenes, an organism which can cause serious and sometimes fatal infections to individuals with weakened immune systems. Although healthy individuals may suffer only short term symptoms such as high fever, severe headache, stiffness, nausea, abdominal pain and diarrhea, Listeria infection can cause miscarriages and stillbirths among pregnant women.


Salmonella, another baceria that sometimes thrives in sprouts, can also can cause serious, occasionally fatal, illness.  The usual symptoms are diarrhea, fever, and cramps that begin within 48 hours of infection and last 4-7 days.   Serious cases require hospitalization.  Salmonella is especially dangerous for young children, the elderly, and others with weakened immune systems.

Raw seed sprouts (such as alfalfa and radish sprouts) have long been touted as a health food.  And there are good reasons for this: they’re an excellent source of many essential nutrients including protein, as well as being a popular, tasty addition to salads and sandwiches. However, unfortunately, sprouts are also a very common source of pathogens (especially salmonella and E.coli) and illness.  FoodSafety.gov (a website from the U.S. Dept. of Health and Human Services) says that, since 1996, there have been at least 30 reported outbreaks of food-borne illness associated with different types of raw and lightly cooked sprouts.  (Two or more cases of the same food-associated illness is considered an outbreak.)


Michele Morrone, author of Poisons on Our Plates, discusses the 27 sprouts outbreaks that occurred from 1996-2004, which caused 1,633 people to become ill. During this period, she says, sprouts accounted for about 40% of all food borne illnesses that were caused by produce and 20% of the total number of food-borne illnesses in the U.S.

Why do sprouts fall victim to pathogens (and people fall victim to sprouts) so frequently?  All fresh produce carries some risk of foodborne illness.  However, unlike other fruits and vegetables, seeds and beans need both warm and humid conditions to sprout and grow.  These conditions are also ideal for the growth of harmful bacteria. Also, not all sprout growers follow the guidelines recommended (but not required) by the FDA in 1999.  Furthermore, in 2004, some 50% of California’s sprout-growing facilities were found to be operating under unsanitary conditions.


To help deal with the problem of contaminated sprouts, FDA guidelines recommend sanitizing seeds with a chemical sanitizer (usually chlorine-based), but this treatment is controversial even though the percentage of chlorine used is very small. The FDA also recommends testing the water used during the sprouting process for the presence of harmful levels of bacteria. Besides the chlorine-based treatment, two other promising methods of decontamination are irradiation and heat treatment (similar to pasteurization). But more research is needed to further evaluate their effectiveness, according to Morrone. 


Whether you buy your sprouts or grow them yourself, there is a risk of contamination and illness if they are eaten raw or only lightly cooked.


Don’t count on a good rinse to wash away contaminants.  When contamination of sprout seeds is suspected, washing the sprouts will not get rid of the bacteria. Just get rid of the sprouts.


To minimize the risk of foodborne illness from sprouts, here’s what the FDA recommends:


• Children, the elderly, pregnant women, and people with compromised immune systems should not eat raw sprouts of any kind (including alfalfa, clover, radish, and mung bean sprouts).

• Cooking sprouts kills the harmful bacteria, so cook them thoroughly.

• If you purchase a sandwich or salad in a restaurant or deli, request that sprouts NOT be added. In other words, the FDA is recommending that people not eat them.  If you are determined to consume raw sprouts despite this recommendation, pay close attention to news about outbreaks to minimize your risk of illness.


For more information about sprouts, click here: http://www.foodsafety.gov/blog/sprouts.html




Poisons on our Plates: The Real Food Safety Problem in the United States by Michele Morrone, 2008.


FoodSafety.gov “Sprouts: What You Should Know”


FDA (U.S. Food and Drug Administration)  “Safe Handling of Raw Produce and Fresh-Squeezed Fruit and Vegetable Juices”


Injured: The FindLaw Accident, Injury, and Tort Law Blog “FDA: Don’t Eat Your Alfalfa Sprouts”


U.S. Dept. of Health and Human Services “Urgent Nationwide Alfalfa Sprout Recall”


“Caldwell Fresh Food Recalls Alfalfa Sprouts Because of Possible Health Risks”


U.S. Dept. of Health and Human Services “Urgent Nationwide Alfalfa Sprout Recall”




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