Date: November 20, 2023
Number: SN23-014
Contact: CDPHpress@cdph.ca.gov

The California Department of Public Health (CDPH) has lifted the shellfish safety notification today related to sport-harvested mussels, scallops, and clams in San Mateo County. The safety notification was issued on July 28, due to dangerous levels of naturally occurring paralytic shellfish poisoning (PSP) toxins that can cause illness or death. Recent testing shows PSP toxins have decreased to safe or undetectable levels for bivalve shellfish in this area. 

The notifications do 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 these products. Shellfish sold by certified harvesters and dealers are subject to frequent mandatory testing to monitor for toxins.

PSP toxins affect the nervous system, producing a tingling around the mouth and fingertips within a few minutes to a few hours after eating toxic shellfish. These symptoms are typically followed by loss of balance, lack of muscular coordination, slurred speech and difficulty swallowing. In severe poisonings, complete muscular paralysis and death from asphyxiation can occur.

You can get the most current information on shellfish advisories and quarantines by calling CDPH's toll-free Shellfish Information Line at (800) 553-4133 or viewing the recreational bivalve shellfish advisory interactive map. For additional information, please visit the CDPH Marine Biotoxin Monitoring Web page.