In recent years, people have raised questions about the ingredients in fast food poultry and beef products, after the infamous image of "pink slime" began circulating across the Internet. Pink slime isn't used in chicken nuggets, but what are "nuggets" actually made of?

“Chicken McNuggets are made with white meat, lightly coated in a tempura batter to ensure that they are crispy on the outside, and juicy and tender in the inside.” At least that's how McDonald’s describes its popular chicken meal on its website. “They are cooked in a Canola oil blend, which provides 0 grams of trans fat per serving.”

Researchers from the University of Mississippi Medical Center were curious as to what fast food chicken nuggets were really made of. After all, they are incredibly popular in the U.S. In 2011, 50 billion pounds of broiler chickens were raised and sold, according to the National Chicken Council. And, about 50 percent of that meat was made into nuggets and similar products. However, the researchers found that for all this meat sold, much of the chicken nuggets we are served  do not contain simply breast meat, as many fast food chains claim.

“Striated muscle (chicken meat) was not the predominate component in either nugget,” the researchers noted in their study. “Fat was present in equal or greater quantities along with epithelium, bone, nerve, and connective tissue.” Epithelium is one of the four types of animal tissue, and usually lines cavities and structures throughout the body. The study ultimately concluded that “chicken nuggets are mostly fat, and their name is a misnomer.”

An earlier study published in the Journal of Food Science and Technology found that up to 30 percent of processed meats are made up of fat. The new study claims that potentially even more than 30 percent of a chicken nugget may be made of fat. Large fast food chains and chicken processors, however, argue that chicken nuggets are made of 100 percent chicken meat and do not contain any disturbing ingredients.

“The only meat used in McDonald’s Chicken McNuggets is chicken breast meat,” McDonald’s states on its website. “The white meat is minced before being shaped into nuggets, and then coated with a specially seasoned batter at our trusted suppliers, such as Keystone Foods.”

On the National Chicken Council’s website, the NCC responds to the question of “What’s really in that nugget?” with, “Chicken. Meat from a chicken, actually. It’s that simple.”

The NCC, which represents big chicken processors in the U.S., goes on to list myths and facts about chicken nuggets, noting that they are not typically made from mechanically separated chicken; “meat glue” is not used to hold chicken nuggets together; and that “experts” like Dr. Casey Owens, associate professor at the Department of Food Science at the University of Arkansas, say “There is no ‘pink slime’ in chicken nuggets.”

As if to make matters worse, the U.S. Department of Agriculture announced recently that it would no longer ban processed chicken imports from four Chinese poultry processors. Prevoiusly, chickens were raised then killed in the States, shipped to China to be processed, and then shipped back to the U.S. to be implemented into fast food and pet food products.

"China does not have the best track record for food safety," The New York Times notes, "and its chicken products in particular have raised questions."

Along with removing the ban, the USDA may be in the process of replacing USDA inspectors on U.S. chicken processing lines with poultry company employees themselves. Although this may seem questionable, the USDA believes these changes, if implemented properly, "would enable [USDA inspectors] to better fulfill our food safety mission."