Though they add a nice crunch and are loaded with protein and vitamins, they can carry a real risk. The U.S. government recommends that the very young, elderly, pregnant and others with compromised immune systems stay away from raw sprouts completely and that anyone who eats sprouts cook them first. Federal officials go so far as to recommend that people ask that raw sprouts not be added to their food at restaurants.
Alfalfa sprouts, bean sprouts and other varieties of the salad topper and sandwich filler have sickened more than 400 people in the United States in the last two years and are blamed for dozens of significant outbreaks globally in the last two decades. Sprouts need warm and humid conditions to grow
- precisely the same conditions required by bugs like E. coli and salmonella to thrive.
The problem, says Dr. Christopher Braden of the U.S. Centers for Disease Control and Prevention, is that sprouts are often hidden. Because they are quietly tucked into salads, sandwiches and other foods, people often don't even know they've eaten them.
"Sprouts are kind of famous in our playbook because they can be what we call a `stealth vehicle' for foodborne outbreaks
- they are typically not served alone and people don't recall that they've eaten sprouts," he said.
There have been at least 30 outbreaks associated with raw or lightly cooked sprouts in the United States in the last 15 years and even more around the world, including a 1996 outbreak in Japan that sickened more than 10,000 people with E. coli.
Bill Marler, a Seattle-based attorney and food safety advocate, has represented hundreds of people sickened by sprouts. He says people should think about them in the same category as they do unpasteurized milk, oysters or other potentially risky foods.
"People in the know in public health don't eat sprouts," Marler said.
German officials said Friday that sprouts caused the deadly outbreak there, although they don't know which kind. The organic farm linked to the outbreak grew a wide variety, including alfalfa, onion and radish. For now, German authorities are recommending people avoid all sprouts.
Sprouts are grown in water from seeds, which are rinsed daily. Officials in Germany say they're not yet sure whether the sprout seeds were infected or whether the sprouts got contaminated by dirty water. Public health agencies have long been concerned about the risks of bacterial contamination of water used to produce sprouts. And E. coli can stick to the surface of sprout seeds.
"They can lay dormant on the seeds for months," said Stephen Smith, a microbiologist at Trinity College in Dublin.