L-cysteine, an important food additive in commercial bread production, is commonly derived from grains, but more cost-effective methods include sourcing it from duck feathers and human hair collected from hairdressing salons. This amino acid, labeled E920 when used as a food additive, helps improve dough elasticity and shelf life. While L-cysteine from human hair was widely used in the past, it has become controversial due to ethical and hygiene concerns. In the European Union, regulations strictly prohibit the use of any form of human remains in food production. However, in some parts of the world, alternative sources such as human hair continue to be utilized in industrial food processing.
