The infamous McRib is back! The McRib only appears in Mcdonald’s for a limited time only throughout the year. As it appears out of the box, the McRib sandwich consists of just five basic components: a pork patty, barbecue sauce, pickle slices, onions, and a sesame bun, but McDonald’s own ingredients list reveals it consists of azodicarbonamide, ammonium sulfate and polysorbate 80. Those are just three of the 70 plus ingredients, 34 are in the bun alone that go into the notorious pork sandwich.

These components are in small enough proportions to be unnoticed. But it’s still a little disgusting and repulsing to know that, for example, the ingredient azodicarbonamide, a flour-bleaching agent that is commonly used to make foamed plastics like in yoga or gym mats and the soles of shoes, is found in the McRib bun. The compound is banned in some countries for example, Europe and Australia as a food additive. The U.S. allows azodicarbonamide to be processed 45 parts per million in commercial flour products, based on analysis of lab testing.

The McRib was originally created due to a shortage of chickens. In 2009 an interview with McDonald’s first executive chef and inventor of the Chicken Nugget, Maxim, Rene Arend, explained how the McNugget was so popular it quickly outstripped chicken supply.

The legendary BBQ sandwich was developed out of necessity. Franchises that didn’t have the McNugget needed a new product — and that’s when Arend scrambled back to the kitchen. 

The entire sandwich packs a whopping 500 calories, 26 grams of fat, 44 grams of carbs, and 980 milligrams of sodium. Next time when you order the popular Mcdonald’s McRib, remember what goes into that plastic based bun, artificially flavored pork patty, and outdated pickles and onions before you blink and its gone.