California health officials are warning consumers not to eat mussels, clams or scallops from Marin County because they may contain dangerous levels of paralytic shellfish poisoning (PSP) toxins. The California Department of Health issued a health advisory Wednesday after mussels harvested from Marin County were found to contain high levels of PSP toxins, but the agency warns that clams and scallops may also carry the toxins. The warning affects only to recreationally harvested shellfish, and does not extend to commercial mussels, clams and scallops, says CDPH, because these products are sold by state-certified harvesters and dealers. PSP toxins affect the central nervous system and can cause serious illness or death in humans. Symptoms of paralytic shellfish poisoning include a tingling around the mouth and fingers a few minutes to an hour after consuming the contaminated food, followed by a loss of balance, lack of muscular coordination, slurred speech and difficulty swallowing. In severe cases, complete muscular paralysis and death from asphyxiation can occur. Cooking will not destroy the toxin, warns CDPH. Marin County is located just north of San Francisco on the coast of California.