Scope of melamine contamination grows

Grain gluten from China is apparently routinely spiked with melamine to make it seem to contain more protein (nitrogen) than it actually does.

This, in the US, has contaminated pet food, hog feed, and now chicken feed. This dailykos.com story has the scoop:
FDA drops the other shoe: Millions ate contaminated chicken

So now many people have eaten melamine-laced chicken. It is still not clear if the contamination has hit food directly consumed by humans.