Kroger is recalling spinach sold at grocery stores in 15 states due to possible Listeria contamination.

The Fresh Selections Tender Spinach brand was sold in 10-ounce packages and had a “best if used by” date of Sept. 16. The grocer says if customers bought the recalled product, they should return it to stores for a full refund or replacement.

Listeria can lead to severe illness for women who are pregnant or people who have a weakened immune system. No illnesses have been reported from the spinach. The recall came after a single package tested positive for the bacteria.

Kroger says the product was sold in Kentucky, Indiana and 13 other states in the South and Midwest.