Ew. So is something being put into supermarket meat, or are those animals breathing something from the air before they die?

I just stuck a magnet to my collarbone but it's a weak attraction if anything. It might even be moisture, it's hard to be sure. My wife and baby, too. More testing required...

EDIT: I keep finding wiki entries that seem like they might be relevant. https://en.wikipedia.org/wiki/Iron_oxide_nanoparticle