By WILLIAM NEUMAN
Published: June 10, 2011
Sprouts are a fixture of salad bars and the epitome of health food to many people. But the reality can be very different.
Stew Milne for The New York Times
Stew Milne for The New York Times
As a horrified Europe learned over the past month, sprouts are a high-risk food for carrying harmful bacteria likesalmonella or the toxic forms of E. coli, according to public health experts.
This year, at least two American growers have recalled sprouts contaminated with salmonella, and outbreaks of illness from tainted sprouts have occurred so often in the United States that health investigators have a special name for them: sproutbreaks.
Many sprout growers try to kill pathogens by soaking their seeds before germination in a concentrated chlorine solution, similar to but much stronger than the disinfectant used in swimming pools. While the Food and Drug Administration recommends a sanitizing step like the chlorine treatment, it does not require it and some growers skip it or use less stringent methods.
German authorities said on Friday that they had conclusively identified sprouts as the cause of the E. coli infections that have swept Europe since early May, killing at least 31 people and sickening about 3,000, including more than 700 with a severe kidney complications.
Epidemiologists in the United States said they were perplexed that it took German authorities so long to identify the culprit.
“I’m just staggered,” said William E. Keene, a senior epidemiologist of the Oregon Public Health Division. “This is basic outbreak investigation 101. This is on the high end of suspect vehicles. You always rule out raw milk, you always rule out ground beef, you always rule out sprouts. It just happens in the beginning steps.”
After a series of outbreaks of sprout-related illnesses in this country and abroad in the 1990s, the F.D.A. began encouraging sprout growers, known as sprouters, to take steps to sanitize their seeds and test their products for pathogens before sale.
The agency also warned the public that uncooked sprouts were a risky food, saying that children, the elderly, pregnant women and those with weak immune systems should not eat raw sprouts. The bacteria that can contaminate sprouts can be destroyed by cooking.
The F.D.A. says there have been at least 30 outbreaks of disease associated with sprouts in this country since 1996. The Center for Science in the Public Interest, an advocacy group that tracks food safety, said that its review of government data revealed 45 sprout-related outbreaks since 1990, including 2,500 illnesses. The group said that it was aware of one death, in a salmonella outbreak in 2003.
One of the most severe E. coli outbreaks ever recorded, in Japan in 1996, was associated with radish sprouts. About 10,000 people, many of them children, fell ill.
Bob Sanderson, president of Jonathan Sprouts in Massachusetts and the head of theInternational Sprout Growers Association, said that it would be wrong to draw conclusions about the safety of American sprouts based on the German outbreak, since growers there may use different methods than their counterparts here. “Fresh food is the most nutritious food and inherently prone to these problems,” Mr. Sanderson said of sprouts and other vegetables. “That’s what makes it fresh. It’s not sterile.”
Mr. Sanderson’s company recalled alfalfa and some mixed sprouts in April after routine federal testing found salmonella in them. Mr. Sanderson said that no illnesses had been associated with his products. After the recall, he said, he improved his testing methods.
Some sprout growers complain that the strong chlorine mixture recommended by the F.D.A. to sanitize seed can be dangerous for workers to handle.
Mr. Sanderson said that he used a lower concentration of chlorine for that reason, but he feels that the tests his company conducts on sprouts as they are growing are sufficient to catch any problems.
Sidney Chang, the owner of Chang Farm, another Massachusetts sprouter, recalled some of his sprouts two years ago after tests found listeria, another dangerous bacteria. Since then, he has built a new, more modern facility and now sanitizes his sprouts with a hot-water process. He also uses a less concentrated chlorine wash.
Experts say they believe sprout seeds can become contaminated in the fields where they are grown. Bacteria can hide inside damaged seeds, where sanitizing steps may not always be able to reach them.
Michelle Smith, an F.D.A. senior policy analyst, said that a single bacterium surviving in a kilogram of seed can be enough to contaminate a batch of sprouts because the way they are grown allows bacteria to spread.
Dr. Smith said that the F.D.A. expected to include new rules for sprouts as it wrote regulations as part of a major food safety law that went into effect this year.