County health officials have linked 11 confirmed and probable cases of norovirus illness to frozen oysters imported from South Korea, according to an announcement made on Tuesday.

Customers who consumed the oysters at 100s Seafood Grill Buffet in Mission Valley between March 31 and April 1 fell ill, with one person requiring emergency room treatment, as per a county statement.

The U.S. Food & Drug Administration has connected the San Diego illnesses to quick-frozen oysters and is advising all restaurants and stores that sell frozen, raw half-shell oysters to inspect their freezers and confirm the origin of their oysters.

To determine their origin, individuals should check for shellfish tag or label information. Oysters processed by JBR (KR 15 SP) in Tongyeongsi, Republic of Korea on 11/27/2023, 1/4/2024, and 2/15/2024 with lot numbers B231126, B240103, and B240214 should not be consumed. These items may be labeled as “Amazing Sea Brand.”

The county is collaborating with the California Department of Public Health to identify other potential retailers in the region.

“If you have consumed these oysters and feel ill, it is important to see your doctor for evaluation,” stated Dr. Wilma Wooten, county public health officer. “If you or someone you live with is sick with norovirus, it is important to wash your hands often and clean common areas to prevent spreading the infection.”

Four months ago, county health officials linked 41 confirmed and probable cases of norovirus to raw oysters imported from a specific harvest location in Northwest Mexico.

Norovirus infection typically causes symptoms such as nausea, vomiting, diarrhea, stomach cramps, fever, and body aches within 12 to 48 hours after consuming contaminated foods. The illness usually lasts for one to three days. Severe vomiting and diarrhea can lead to dehydration, which may require medical attention, especially in young children, older adults, and individuals with other underlying health conditions.

San Diego County’s Epidemiology Program and Department of Environmental Health and Quality are collaborating with the California Department of Public Health to further investigate illnesses associated with oysters.

To report illness related to dining out or purchasing from wholesale food locations to the county, call 858-505-6814 or email fhdepi@sdcounty.ca.gov.