As the cases of gastrointestinal illnesses linked to oysters rises to more than 150, the Los Angeles County Department of Public Health is directing the public to avoid eating bivalves that originated in parts of Mexico.

Diners in San Diego, Orange and Los Angeles counties have been warned about eating raw oysters, as more than 40 people were believed to have been infected with noroviruses as of Tuesday.

But on Wednesday, with suspected infections topping 150, health officials directed their advisories toward the source.

“At this time, Public Health is warning consumers not to eat raw oysters from Laguna De Guerrero Negro, Baja California, Mexico; Laguna Manuela, Baja California, Mexico; and Bahia Salina, Sonora, Mexico because they may be linked to outbreaks of norovirus illnesses in California,” Public Health said in a news release.

To avoid being sickened, diners should ask the restaurant and/or oyster vendor where the mollusks were harvested.

If you’ve been sickened by eating raw oysters or by consuming something else, you’re encouraged to report that to the California Department of Public Health using this link.