Is benzoyl peroxide used in food?

This one sounds like a rumour and is not. The same substance sold at 2.5 to 10 percent for acne is separately permitted in food, under an entirely different regulation, to make things whiter.

What is permitted

The US regulation affirms Benzoyl peroxide as generally recognised as safe when used as a bleaching agent, in three places:

Flour.

The milk used to make named cheeses, the list including Asiago, blue, Caciocavallo siciliano, Gorgonzola, Parmesan and reggiano, Provolone, Romano, and Swiss and emmentaler.

Whey that has been coloured with Annatto, so that the finished product still meets the description of whey.

That third one is a small piece of industrial housekeeping worth appreciating: cheese made with annatto colours the whey orange as a side effect, and whey is then sold as a powder that buyers expect to be pale.

The limits are specific

The cheese standard does not leave the amount to judgement. Benzoyl peroxide is capped at 0.002 percent of the weight of the milk being bleached, with the accompanying carriers limited to six times that.

Two further conditions make the provision more careful than a bare permission.

Vitamin A must be added back. Bleaching destroys vitamin A and its precursors in the milk, and the standard requires the curd to be supplemented to compensate for what was lost.

Artificial colouring is then forbidden. A producer who bleaches this way may not colour the result back to look richer. The regulation closes that door deliberately.

Why you will never see it on the label

Because it acts on an ingredient before the food exists, and is not itself an ingredient of the finished cheese.

That is a real category in food labelling and not a loophole: things that do a job during manufacture and have no function in the final product are treated differently from things that are in it. It does mean a reader cannot tell a bleached cheese from an unbleached one, and knowing that a category like this exists is more useful than any single fact inside it. The guide to reading a label spends as much time on what is absent as on what is printed.

Should this worry you

We are not going to tell you it should or should not, because that is not a question a label reader can answer, and the honest position is that the regulation sets a small limit and requires a nutrient to be restored.

What we will say is that this is a good example of why regulatory documents are worth reading directly. The fact is public, precise and entirely undramatic, and it is nowhere near the shape it takes when it travels as a claim about acne cream in your cheese.