FDA warns public not to eat possibly radioactive shrimp sold at Walmart
FDA warns public not to eat possibly radioactive shrimp sold at Walmart
abcnews.go.com
FDA warns public not to eat possibly radioactive shrimp sold at Walmart

FDA warns public not to eat possibly radioactive shrimp sold at Walmart
FDA warns public not to eat possibly radioactive shrimp sold at Walmart

This is perhaps the most 2025 hed I've seen in 2025. (and a bit misleading, given that the data show that "possibility" to be 0%)
That said, where on the packaging line was there just some Cs-137 hanging out? That's not the sort of thing you get at Cash-'n'-Carry. Grad student storing it there ahead of a trip to a lake?
To be honest; I would imagine that the Cs-137 is a product of illegal fishing. Fishermen are told not to fish in contaminated areas; but may do so anyways out of desperation for a catch they can sell.
I remember nuclear disasters near SE Asia and Japan over the last decade. It is also true that Shrimp are also, not so unimportantly, Bottom-Feeders. As Bottom of the Ocean feeders. They literally hoover up the soil at the bottom of the ocean and eat the microbiological life living there. With recent nuclear disasters; I think it's possible some orphan Cesium got down there.
Naturally this is just my theory; based on my limited college educated knowledge of biology and the food web.
That's not really an explanation of how the containers had caesium but no shrimp tested positive, though.