Federal regulators have uncovered possible radioactive contamination in Indonesian spices, just as recalls of potentially tainted shrimp continue to expand. The discovery heightens concerns about the origin and scope of these unusual food safety threats.

The U.S. Food and Drug Administration has issued a warning about potential Cesium-137 contamination in some packages of Great Value frozen shrimp sold at Walmart. The agency’s alert urges consumers to stay tuned for additional guidance while it assesses the scope of the risk.