Which foods contain casein?

Casein is the main protein in milk, roughly four fifths of it. So the first answer is simple and not very useful: every dairy food contains it.

The list worth having is the second one.

Where it is most concentrated

Cheese, by a distance. Cheesemaking works by curdling milk so the casein clumps together, and the clump is the cheese. What drains away is Whey. Hard cheeses are the most concentrated form of casein most people ever eat.

Then milk, yoghurt, cream, butter in small amounts, ice cream, milk chocolate, and anything made with those.

The ones people miss

This is the part that matters, because these products do not read as dairy.

Non-dairy creamer. The classic case. Many contain sodium caseinate, which is casein, and are still lawfully sold as non-dairy because that term is not a promise of no milk protein.

Some dairy-free and vegan cheeses. Not all, and it is getting rarer, but casein is what makes cheese stretch and melt, so some plant-based cheeses have historically used it to get the texture right. A vegan certification mark rules it out; the words “dairy-free” alone do not always.

Protein bars and powders. Casein is sold deliberately as a slow-digesting protein, so it is often the point of the product rather than an accident. Micellar casein and calcium caseinate are both casein.

Processed and deli meats. Caseinates are used as binders in some sausages, hams and reformed meats.

Bread and baked goods. Milk powder or caseinate for softness and browning.

Crisps and savoury snacks. Cheese and sour cream flavourings, and sometimes caseinate in the seasoning of flavours that are not obviously dairy.

Some medicines and supplements, where milk derivatives are used as excipients.

What it is called on a label

This is the part to memorise, because casein hides behind more names than most ingredients:

Casein, caseinate, sodium caseinate, calcium caseinate, potassium caseinate, magnesium caseinate, micellar casein, casein hydrolysate, milk protein, milk solids, curds, rennet casein, paneer.

The good news is that none of these can appear without milk being declared. Milk is a major allergen, so wherever these names appear, the allergen statement has to carry milk too.

The rule that actually saves time

Do not read the ingredient list first. Read the allergen statement.

Milk is declarable everywhere with allergen rules, so “contains milk” catches casein under all thirteen of the names above at once, and it is one line rather than forty. Turn to the full list only when you want to know which form it took, or when there is no allergen statement to read.

That advice is unusual on this site, which normally sends you to the ingredient list. Here the allergen line is genuinely doing the work, because milk is one of the things labelling law takes seriously. The gap between what the law takes seriously and what a particular reader needs is the subject of the page on reading labels with a food allergy.

If the confusion that brought you here is between milk protein and milk sugar, that is a separate and very common one, covered on the page on casein and lactose.