Mechanically separated chicken is flesh that has been stripped from a chicken carcass after the most popular cuts of meat have been removed. Raw chicken bones are forced through a special sieve to clean them of flesh. The meat from these bones is made into an edible paste.
Mechanically separated chicken mostly consists of scraps of flesh, with some added calcium and phosphorus from close contact with the bone, and other tissue such as skin, nerves and veins mixed in. It is not sold directly to consumers, but instead is made into a variety of processed meat products, such as chicken franks. Although mechanically separated chicken is associated with chicken nugget production, brands such as McDonald's that use all-white meat do not use mechanically separated chicken to make their nuggets. In mechanically separated chicken paste, dark meat and white meat are mixed together too thoroughly to claim that a product is all-white meat.