The Orange County Health Care Agency in California warned consumers Saturday to avoid raw and undercooked oysters harvested from the southern part of the Hood Canal in Washington state after nearly a dozen people became ill after eating them.
Three of the people were from Orange County. Most of the others were from Northern California, said agency spokesperson Deanne Thompson.
The Washington State Department of Health has closed the growing area associated with the illness and has asked commercial oyster harvesters and dealers who obtained oysters from this area to recall them.
The bacteria in the oysters is always present, but it multiplies in the summer when water temperatures rise, Thompson said.
The Food and Drug Administration (FDA) has also advised consumers who have recently purchased oysters should check with the place of purchase and ask if the oysters were harvested from the affected area.
Symptoms of vibriosis, caused by the vibrio parahaemolyticus bacteria, include diarrhea, abdominal cramps, nausea, vomiting, headache, fever and chills and usually appear within 24 hours after eating the oysters. Severe disease is rare and occurs mostly in people with compromised immune systems.
Vibriosis is a general term referring to an infection by any member of the large group of Vibrio bacteria. The bacteria that causes cholera is in this group.
The diarrhea-causing Vibrio parahemolyticus is a relatively harmless infection, but Vibrio vulnificus infection, though rare, can lead to blood poisoning and death in many cases.
In addition to Washington and California, records indicate that raw oysters from the area were distributed to British Columbia, Florida, Hawaii, Idaho, New York, Oregon, Hong Kong, Malaysia, and Singapore.
The FDA said that those with weakened immune systems, including those affected by AIDS, chronic alcohol abuse, liver, stomach, or blood disorders, cancer, diabetes, or kidney disease, should avoid eating raw oysters, regardless of where they are harvested.
The warning extends only to raw oysters. The FDA said consumers could continue to eat properly cooked oysters.
The FDA made these recommendations for purchasing and preparing oysters:
Purchase oysters with the shells closed; throw away any oysters with shells already opened.
Never allow raw seafood to come into contact with cooked food.
Boil oysters until the shells open and then boil for an additional three to five minutes.
When steaming oysters use smaller pots with fewer oysters. Using large pots or steaming too many at once may cause uneven heat distribution, which may result in some oysters being under-cooked.
Discard any oysters that do not open when cooked.
Boil or simmer shucked oysters for at least three minutes or until the edges curl.
Fry oysters at 375° F for at least three minutes.
Broil three inches from heat for at least three minutes.
Bake at 450° F for at least 10 minutes.