(NEXSTAR) – A Kirkland-brand ahi tuna product has been recalled from Costco locations in 33 states over concerns that a component may be contaminated with listeria monocytogenes, according to a notice posted by the U.S. Food and Drug Agency.

The recall was issued after the Western United Fish Company of Kent, Washington — which produces the product for Costco — was notified that some of the green onions used in the product had tested positive for listeria monocytogenes. The company said that a “root cause” for the positive test result had not been identified as of Saturday.

The product was sold at Costco locations in 33 states, according to the notice: Alabama, Alaska, Colorado, Connecticut, Delaware, Florida, Georgia, Idaho, Indiana, Louisiana, Maine, Maryland, Massachusetts, Minnesota, Mississippi, Missouri, Montana, Nebraska, New Hampshire, New Jersey, New Mexico, New York, North Carolina, Ohio, Oregon, Pennsylvania, South Carolina, Tennessee, Texas, Utah, Virginia, Washington, and Wisconsin.

Affected packages can be identified by the packing date of Sept. 18, 2025, and the sell-by date of Sept. 22, 2025.

Customers who purchased the Ahi Tuna Wasabi Poke products are urged to throw them away and contact Costco for a refund. Customers with additional questions for the Western United Fish Company (which does business as Annasea Foods Group) can contact the company by phone at 1-425-558-7809 or email at info@annasea.com.

Listeriosis, an infection caused by foodborne listeria monocytogenes bacteria, affects roughly 1,600 people each year, around 260 of whom die, according to the Centers for Disease Control and Prevention (CDC). Those at the highest risk are pregnant women, newborns, young children, those over 65 and those with weakened immune systems. In pregnant women, listeria infection can cause miscarriages, stillbirths or preterm labor.

Symptoms of listeria infection include fever and diarrhea, along with headache, stiff neck, nausea, loss of balance, abdominal pain, confusion and convulsions, according to the CDC and FDA. Pregnant women, however, typically have milder symptoms, the CDC says.

The Western United Fish Company said no illnesses linked to the recalled ahi tuna products had been reported as of Saturday.