Origin
Iron oxide naturally occurs in the environment in minerals. Iron oxide can be obtained from hematite, for example. However, E 172 is synthetically produced through a chemical process for industrial production because extraction from minerals involves high effort.
Usage
E 172 can be used without restriction as a food coloring. Primarily, E 172 is found in foods such as sweets, olives, dragees, coatings, and cheese rinds, for example.
Risks
Iron oxide is harmless to the human body and can be consumed without concern. E 172 is indigestible and is excreted by the body.