E172: Iron oxides and iron hydroxides

What is E172?

E172 covers iron oxides and iron hydroxides, inorganic pigments that give yellow, red, brown and black colours. Chemically they are the same compounds as rust and the natural earth pigments ochre and umber.

Origin and production

Food-grade iron oxides are produced synthetically from iron salts under controlled conditions, rather than mined, to ensure high purity and low levels of contaminants. They contain no plant or animal material.

Why is it used?

Iron oxides are very stable colours that resist light and heat, so they are used to colour tablet and capsule coatings, cheese rinds, sausage casings, vegetarian sausages and meat analogues, and decorations on chocolates and cakes.

Vegan, vegetarian and halal

E172 is mineral in origin and suitable for vegans and vegetarians. It raises no particular halal or kosher concerns.

Safety and regulation

Iron oxides and hydroxides are authorised as food colours in the European Union, and EFSA re-evaluated them in 2015, noting that available data did not raise concern at reported uses but requesting additional information on particle size. They are also widely used in medicines.

Common in