A Seattle seafood distributor has recalled more cooked and frozen shrimp sold at Kroger grocery stores across the United States because of ongoing concerns about potential radioactive contamination.

Aquastar Corp. recalled nearly 157,000 additional pounds of shrimp because of possible contamination with cesium 137, a radioactive isotope. The new recall includes nearly 50,000 bags of Kroger Raw Colossal EZ Peel Shrimp, about 18,000 bags of Kroger Mercado Cooked Medium Peeled Tail-Off Shrimp and more than 17,000 bags of AquaStar Peeled Tail-on Shrimp Skewers.

The products were sold between June 12 and Sept. 17 at grocery stores in more than 30 states. They include Bakers, City Market, Dillons, Food 4 Less, Foodsco, Fred Meyer, Fry’s, Gerbes, Jay C, King Soopers, Kroger, Mariano’s, Metro Market, Pay Less Supermarkets, Pick ‘n Save, Ralph’s, Smith’s and QFC.

The company previously recalled shrimp products in August.

The new recall is the latest action in an ongoing investigation of potential contamination with cesium 137, a byproduct of nuclear reactions, according to the U.S. Food and Drug Administration.