Kroger Co. is recalling certain spinach items at some of the supermarket operator’s stores in 15 states amid concerns they may be contaminated by listeria.

The recall involves 10 ounce packages of Kroger Fresh Selections Tender Spinach with the UPC code 0001111091649. The product was supplied by NewStar Fresh Foods LLC.

Kroger said it has removed the items from store shelves and is asking customers to return the product for a refund or replacement.

The recall includes Kroger stores–as well as a number of other supermarkets the company operates under other brands–in Alabama, Georgia, Illinois, Indiana, Kansas, Kentucky, Michigan, Missouri, Nebraska, North Carolina, Ohio, South Carolina, Tennessee, Virginia and West Virginia.