Although there’s been no confirmation of radiation risk in food purchased at Walmart stores, the FDA said that it has detected unsafe levels of cesium-137 contamination at four U.S. ports. This contamination likely suggests that the shrimp was packaged in unsanitary conditions.

Further testing revealed a small amount of the Cesium-137, or Cs-137, actually in one sample of breaded shrimp (at which port, they didn’t say). The discovery was enough for the FDA to recommend that Walmart stores stop selling specific Great Value shrimp products,