The McRib was only back through November 14th, but after reading this, you may not be looking forward to it's return...
In analyzing the contents of the mysterious sandwich, the reconstituted pork-based patty probably contains tripe, heart, and scalded stomachs.
That may sound a bit gross to some, but they're all edible meats already found in products like sausages.
Surprisingly, the bun seems more troubling. It contains a tiny amount of azodicarbonamide, which is banned as a food additive in Europe and Australia.
The flour-bleaching agent is often used in foamed plastics, like those found in gym mats and shoe soles.
On the other hand, when one order a McRib it's for the novelty, not because it's the foundation of a healthy diet.