Article 2 of the regulation defines an animal by-product as any part of an animal carcass or any material of animal origin not intended for human consumption. They are a product of the livestock and food industry, particularly from food processing and dairy plants and include animals which die on farm, surplus or waste materials from slaughterhouses and a range of surplus or rejected foodstuffs including catering wastesthat contain products of animal origin whether cooked or uncooked. The regulations divide animal by-products into 3 categories based on their potential risk to animals, the public or to the environment, and sets out how each category must or may be disposed.

The regulation restricts the type of by-products that may be used for feeding animals, so that only material fit for human consumption may be used for livestock and pet feed. The regulation also prohibits intra species recycling and the feeding of catering waste to livestock.