Some packages of Great Value frozen shrimp sold at Walmart are at risk for potential for Cesium-137 contamination, the FDA says.

Days after the FDA issued a do-not-eat warning about imported shrimp sold at Walmart, a Florida company actually issued a recall of that shrimp and a California company recalled shrimp sold under five other brands.

The FDA asked Walmart to recall frozen shrimp over potential radioactive contamination. But what's the real risk level?