Bologna is defined by the U.S. Department of Agriculture as "made of one or more different kinds of chopped or ground meats which have been seasoned, cooked and/or smoked."
Bologna's most common meat mixtures include beef, pork, turkey, and chicken. It is then ground together or blended, then filled into a casing and cooked for consumption.
This concoction of meat scraps is then often sliced into thin pieces that complete a lunchtime sandwich. It’s also notable that American and Italian bologna are quite different.