SANTA CRUZ, Calif. -

The California Department of Public Health is warning consumers not to eat recreationally harvested bivalve shellfish from Monterey or Santa Cruz counties due to dangerous levels of a naturally occurring toxin that can cause illness or death. That includes mussels, clams or whole scallops.

Dangerous levels of domoic acid have been detected in mussels from this region. This toxin, also known as Amnesic Shellfish Poisoning, can cause illness or death in humans. No cases of human poisoning from domoic acid are known to have occurred in California.

The warning doesn't pertain to commercially-sold clams, mussels, scallops or oysters from approved sources. State law permits only state-certified commercial shellfish harvesters or dealers to sell these products. Shellfish sold by certified harvesters and dealers are subject to frequent mandatory testing to monitor for toxins.

Symptoms of domoic poisoning can occur within 30 minutes to 24 hours after consuming toxic seafood, and can range from headaches and vomiting to seizures, disorientation, permanent loss of short-term memory or even death.

For more information about shellfish poisoning and warnings, call the state's tollfree shellfish information line at 800-553-4133. More information is also available online.