This warning does not apply to commercially sold clams, mussels, scallops or oysters. State-certified commercial shellfish harvesters or dealers are permitted to sell these products which are subject to frequent mandatory testing to ensure they are safe for consumers.
Paralytic shellfish poisoning (PSP) and domoic acid poisoning (DAP) are both linked to microscopic plankton that are concentrated in filter-feeding animals. PSP affects the human central nervous system producing a tingling around the mouth and fingertips within a few minutes to a few hours after eating toxic shellfish. DAP can occur within 30 minutes to 24 hours after eating toxic seafood. More information about the quarantine, PSP and DAP can be found on the Mussel Quarantine Frequently Asked Questions web page at the California Department of Public Health. http://www.cdph.ca.gov/Pages/MusselQuarantineFAQ.aspx.
The quarantine usually lasts from May 1 through October 31. The quarantine began earlier this year because testing has detected elevated levels of domoic acid and high numbers of algae that produce this toxin.
To receive updated information about shellfish poisoning and quarantines, call CDPH toll-free “Shellfish Information Line” at (800) 553-4133. You may also receive additional information from the California Department of Public Health at http://www.cdph.ca.gov.