The California Department of Public Health is advising people not to eat sport-harvested mussels along the California coast starting Friday, May 1 through at least October 31.
The annual warning applies to all mussel species and is in effect to protect the public against poisoning that can lead to serious illness.
Officials say commercially harvested shellfish from restaurants or fish markets may be safely eaten.
Commercial harvesters in California are certified by CDPH and subject to strict testing requirements to make sure that all oysters, clams, mussels and scallops entering the marketplace are free of toxins.
The annual mussel warning is designed to prevent paralytic shellfish poisoning, or PSP, and domoic acid poisoning, also known as amnesic shellfish poisoning.
Both conditions stem from naturally occurring toxins linked to plankton consumed by shellfish, including mussels and clams. Cooking does not destroy the toxins.
Early symptoms of PSP include tingling of the lips and tongue, which may begin within minutes of eating toxic shellfish.
Those symptoms are typically followed by a loss of balance, lack of muscular coordination, slurred speech and difficulty swallowing.
