Green onions at high risk of carrying virus, experts say

The way the onion is grown and the difficulty in cleaning it are behind the risk.
HARRISBURG (AP) -- While investigators work to pinpoint the cause of a western Pennsylvania hepatitis A outbreak that has killed three people and sickened more than 500, some food safety experts say green onions are particularly hard to keep clean.
Luke LaBorde, assistant professor of food science at Penn State University, said that the way green onions are grown and eaten, even the structure of the onion itself, can make them particularly likely to transmit diseases such as hepatitis A.
A study by the U.S. Food and Drug Administration found that green onions were more likely to be contaminated with Shigella bacteria than many other vegetables. Shigella, like hepatitis A, is most often transmitted when contaminated fecal matter comes into contact with food and is eaten.
FDA spokeswoman Kimberly Rawlings said she didn't know of any studies that showed green onions were more likely to carry hepatitis A than other produce.
Contamination possibility
Green onions stay low to the ground, LaBorde said, with the bulb below the ground and the shoots sticking up. If human or animal waste is used as fertilizer, or if contaminated water is used to irrigate the field, the virus can easily work its way down into the plant.
And once the plant is contaminated, it's almost impossible to clean because of the onion's many layers, said Dr. Ronnie Martin, chair of family medicine at Nova Southeastern University College of Osteopathic Medicine in Fort Lauderdale, Fla.
"If I contaminated a large field of green onions, and it got down inside the top of that growing onion, I would almost have to slice down each one of those layers and wash the whole thing inside and out," Martin said.
Martin said the virus can be killed by thoroughly cooking food, but green onions often are eaten raw or only lightly cooked.
But other than cooking or washing food, little can be done to fight contamination, LaBorde said.
"A lot of people are working on ways to decontaminate food, but it's so tough," LaBorde said. "There are so many nooks and crannies. It's like looking in the Grand Canyon for a person. There's too many places for them to hide."
Unusually large outbreak
The hepatitis A outbreak in Beaver County is thought to be the nation's largest on record. The Chi-Chi's restaurant at the Beaver Valley Mall in Monaca has been shut down, and the restaurant chain removed green onions from kitchens at all its 100 locations, said Bill Zavertnik, chief operating officer of the Louisville, Ky.-based company.