Video: What are McDonald's McRib Patties Made Of?

What exactly goes inside a McDonald's McRib? Is it pork or beef? Is the shape important? Why call it a McRib if there's no rib in the sandwich? Does the McRib contain the same plastic found in yoga mats?

The promotional campaign "Your Questions, Our Food" aims to reveal the truth about what's in McDonald's food. Host Imahara has already gone behind the scenes at a food-processing plant to get the facts on whether McDonald's uses pink slime in its burgers. See the videos here: http://www.farms.com/news/mcdonald-s-usa-launches-your-questions-our-food-82864.aspx

The below video, the second installment. addresses the question "What are McRib patties made of?":