McRib Returns
Pork for the McRib is supplied in large part by Smithfield Farms, which has come under legal pressure from The Humane Society for its use of gestation crates. McDonald's Web site

The craze for McDonald's limited time offer of the McRib has begun again, but consumers might want to take a look at some of the item's ingredients before running out to order one.

If images of the barbecue sauce dripping McRib didn't already turn you off, McDonald's use of azodicarbonamide should do the trick.

McDonald's uses the chemical as one of 34 ingredients in the McRib bun, but the ingredient is actually commonly used to make floor mats, soles of athletic shoes, and other non-edible items.

The United States allows up to 45 parts per million for food -- McDonald's utilizes the maximum -- but Europe and Australia have banned using it as a food additive, according to Time.

The United Kingdom classified it as a respiratory sensitizer and determined that it could cause asthma to those that consumed it. It also could possibly cause allergic reactions to those allergic to food dyes, according to the UK Health and Safety Executive.

If that hasn't effectively scared you away from the McRib, Time notes that other components of the popular sandwich aren't particularly healthy for you. The 500 calorie sandwich is filled with 980 mg of sodium -- more than half your recommended daily intake -- and 10 g of saturated fat.

The unhealthy sandwich consists of a ground pork patty, pickles, onions, and barbecue sauce on a six-inch bun. It was first introduced in 1982 and appears infrequently in McDonald's stores during specific promotions.

This current promotion will last until Nov. 14 and then those looking for an azodicarbonamide fix will have to stake out their local shoe store or gym.