Doubts About Sprouts

Aug. 20, 2001 -- Say the words "health food," and many people immediately think of tofu and sprouts. Yet sprouts could be anything but healthy if they're served raw. Left uncooked, that tangled pile of seeds and stemmy greens could be crawling with bacteria, which can cause serious or even fatal cases of food poisoning.

Public health officials in California looked at six outbreaks of food poisoning associated with contaminated alfalfa and clover sprouts occurring in the state from 1996 to 1998. Five of the outbreaks were caused by bacteria called Salmonella; the sixth was caused by a strain of E. coli bacteria commonly found in tainted meat.

The health experts estimate that close to 23,000 people developed food poisoning or urinary tract infections from contaminated sprouts, which were traced to three different growers. Any of several different sources could have caused the germ invasion, including infected seeds, unclean water used to irrigate crops, animal manure used as fertilizer, or livestock grazing on crops.

"Although sprouts are often touted as a health food, they are potentially hazardous and can cause significant [illness] and even death," write Janet C. Mohle-Boetani and colleagues in the Aug. 21 issue of the journal Annals of Internal Medicine.

Since there is no reliable way of getting rid of all contaminants from the seeds, the researchers recommend that children, the elderly, and people with weakened immune systems should avoid eating raw sprouts.

"With the current technology, there's no method that completely eliminates [disease-causing organisms] from alfalfa or clover seeds, so consumers need to be aware that alfalfa or clover sprouts can cause [food poisoning] or urinary tract infections," says Mohle-Boetani, medical epidemiologist for the California Department of Health Services.

She tells WebMD that raw sprouts should not be served at preschools, daycare centers, schools, hospitals, or nursing homes. In addition, healthy people who want to reduce their risk for food-borne illness should also avoid uncooked sprouts.

Although virtually any kind of fruit or vegetable can be contaminated with disease-causing bugs, sprouts of any variety, including mung bean sprouts found in Chinese food, appear to be particularly good vehicles for passing on bad bacteria to people. For example, an outbreak of E. coli that occurred in 1996 among pupils at 47 Japanese schools was eventually traced to the use of white radish sprouts from a single supplier.

Mohle-Boetani tells WebMD that while proper washing and handling will likely reduce levels of harmful bacteria on smooth-skinned fruits and vegetables such as tomatoes, "with sprouts, the contamination is in the sprouts themselves, and you just can't get it out."

Judy Harrison, PhD, an extension foods specialist in the department of Food and Nutrition at the University of Georgia at Athens, explains that "the way that sprouts are produced is that you have a seed and you have to keep it in warm, moist conditions in order for it to sprout, and what you have is a perfect environment for bacterial growth. So if seeds are contaminated with [disease-causing] bacteria, then when they are put in those conditions to sprout, the bacteria will just go wild."