Formation of mutagens in beef and beef extract during cooking.

Mutagens, distinguishable from benzo[a]pyrene and from mutagenic amino acid and protein pyrolysis products, are formed when ground beef is cooked in a home hamburger cooking appliance or when beef stock is concentrated, by boiling, to a paste known commercially as beef extract. "Well-done" hamburgers contain about 0.14 part per million of the mutagens, and beef bouillon cubes which contain beef extract about 0.1 part per million. Since such mutagens may be potentially carcionogenic and are formed during ordinary cooking procedures, their occurrence raises questions about possible risks to human health.