(NEXSTAR) – A Kirkland-brand ahi tuna product has been recalled from Costco locations in 33 states due to concerns that one of its components might be contaminated with listeria monocytogenes, as indicated by a notification from the U.S. Food and Drug Agency.

The recall came about after the Western United Fish Company of Kent, Washington — which manufactures the product for Costco — was informed that some of the green onions in the product had tested positive for listeria monocytogenes. The company mentioned that as of Saturday, a “root cause” for the positive test result had not been pinpointed.

The product was available at Costco stores 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 should discard them and reach out to Costco for a refund. Those with additional inquiries for the Western United Fish Company (operating as Annasea Foods Group) can contact the company via phone at 1-425-558-7809 or email at info@annasea.com.

Listeriosis, an illness caused by foodborne listeria monocytogenes bacteria, affects approximately 1,600 people annually, with about 260 fatalities, as per the Centers for Disease Control and Prevention (CDC). The individuals most at risk include pregnant women, newborns, young children, seniors over 65, and those with weakened immune systems. In pregnant women, listeria infection can lead to miscarriages, stillbirths, or premature labor.

Symptoms of a listeria infection include fever and diarrhea, along with headache, stiff neck, nausea, loss of balance, abdominal pain, confusion, and convulsions, as stated by the CDC and FDA. Pregnant women, however, generally experience milder symptoms, according to the CDC.

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