MARIN COUNTY (CBS SF)— The California Department of Public Health has issued a warning against eating recreationally harvested mussels, clams or whole scallops from Marin County.

Dangerous levels of paralytic shellfish poisoning toxins have been found in mussels in the county, and clams and scallops may also pose a health risk, the department’s spokeswoman Anita Gore said.

The naturally occurring toxins can cause illness or deaths in humans, Gore said.

The toxins affect the central nervous system and produce a tingling around the mouth and fingertips within a few minutes to a few hours after they are eaten.

The symptoms are followed by a loss of balance, lack of muscular coordination, slurred speech and difficulty swallowing.

Complete muscular paralysis from asphyxiation can occur in severe poisoning cases, and cooking does not destroy the toxin, Gore said.

The warning does not apply to commercially sold clams, mussels, scallops or oysters from approved sources. State law permits only state-certified commercial shellfish harvesters or dealers to sell the products, Gore said.

Shellfish sold by certified harvesters are subject to frequent mandatory testing.

The warning is separate from the annual mussel quarantine that was extended from Oct. 31, 2012, for Del Norte and Humboldt counties and is still in effect, Gore said.

Updated information on shellfish poisoning and quarantines is available at the public health department’s toll free information line, (800) 553-4133.

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