Benzoyl peroxide is a peroxide compound used to bleach flour. Benzoyl peroxide is also used cosmetically and medicinally to bleach hair and teeth and to treat acne.
At residue levels present in food, benzoyl peroxide is not assoicated with health concerns. Added benzoyl peroxide decomposes easily to chemicals such as benzoic acid. Small amounts of benzoyl peroxide are used when treating flour and residue is minimal. Within nine days benzoyl peroxide residue drops below 11 parts per million, and within three months benzoic acid residue drops below 6 parts per million. In mice whose skin was treated with high concenctrations of benzoyl peroxide, the chemical had a carcinogenic effect.
The use of flour bleaching agents is prohibited in the UK.