One of the 70 different ingredients in a McRib sandwich
is azodicarbonamide, "a flour-bleaching agent most
commonly used in the manufacture of foamed
plastics like gym mats and the soles of shoes." But
this ingredient only accounts for its texture; it is not
what gives the McRib its distinctive flavor. That
is produced by the “pig bits like tripe, heart, and
scalded stomach.”