The Food and Drug Administration warned consumers Friday against eating the internal organs of Dungeness crab harvested off the coasts of California, Oregon and Washington because they may contain a harmful toxin.
Although the crab meat itself is safe to eat, the viscera, or internal organs, may contain domoic acid, a naturally occurring toxin produced by marine plankton, FDA Commissioner David A. Kessler said.
Most consumers eat only the crab meat, but some ethnic recipes call for use of the viscera of Dungeness crab, the FDA said in a statement.
The Washington Department of Fisheries closed its crab fishery early this month after substantial levels of domoic acid were detected in crab viscera.
Oregon officials suspended crabbing on Dec. 11 at the request of crab fishermen. California suspended crabbing on Dec. 14.
The crab meat has not been found to be tainted by unsafe levels of domoic acid, the FDA said. However, the states have issued consumer warnings about consumption of Dungeness crab viscera.
Oregon and California reopened their crab fisheries on Sunday after deciding that the meat itself was safe. Washington reopened its waters to crabbing on Tuesday.
Oregon banned the harvest of razor clams and mussels on Nov. 15 after the toxin was first detected in shellfish samples. That ban remains in effect.
It is the first reported outbreak on the West Coast, the FDA said, adding that the conditions that cause plankton to produce the toxin are not known.
High levels of domoic acid can cause amnesic shellfish poisoning. Mild symptoms are abdominal cramps, diarrhea and nausea.
Symptoms of severe cases usually show up within 48 hours, and include headache, dizziness, facial grimace, disorientation, short-term memory loss, excessive bronchial secretions, breathing problems, coma and possibly death.
In November, 1987, four deaths and several severe illnesses in Montreal were linked to mussels contaminated with domoic acid. Canadian officials now routinely test for the presence of domoic acid at about 200 sites.
Dungeness crab also is harvested in waters off Alaska and British Columbia, but no problems with the toxin have been reported there.
Officials in Washington, Oregon and California and at the FDA began monitoring several species of shellfish last month after 11 mild cases of amnesic shellfish poisoning were reported.