Milk

What a milk allergy is

A milk allergy is a reaction to the proteins in cow’s milk, chiefly casein and the whey proteins. Casein makes up the bulk of the protein in milk and is the part that curdles; whey is what stays liquid. Both are separated out industrially and sold as ingredients in their own right, which is why milk shows up in products that have nothing to do with the dairy aisle. This is also where milk differs from most allergens: it rarely hides behind a folk name or a translation. It hides behind chemistry.

It is worth separating this from lactose intolerance, because the two send you to opposite parts of the label. Lactose is the sugar in milk, and lactose-free products are made from milk. If protein is the problem, the “lactose free” flash on the front of the carton is not the claim you need.

The names that do not say “milk”

Casein is the main protein in milk. It is added to processed meats, some breads, coffee whiteners and — notoriously — to “non-dairy” creamers and a few soy or almond cheeses, where it does the melting and stretching that plant proteins do badly. Rennet casein and hydrolysed casein are the same protein prepared differently.

Caseinate — sodium, calcium or potassium caseinate — is casein turned into a salt so it dissolves. It is standard in coffee whiteners, protein bars, instant soups and whipped toppings.

Whey, whey protein concentrate and whey protein isolate are the liquid fraction. Whey is cheap and functional, so it is everywhere: milk chocolate, crisps and savoury seasonings, bread, sausages, and nearly every sports protein powder.

Lactalbumin and lactoglobulin are individual whey proteins, listed by name on older or more technical labels. Lactoferrin is another milk protein, added to some supplements and infant products.

Lactose is milk sugar, but food-grade and pharmaceutical lactose carries residual milk protein with it. It is used as a bulking agent and as a tablet filler, which is why medicines and dry-powder inhalers sometimes have a milk warning on the leaflet.

Milk solids, milk solids-non-fat and non-fat or skimmed milk powder are simply dried milk, spelled in a way that scans past the eye as processing jargon.

Buttermilk, butterfat and butter oil are dairy. Ghee is clarified butter — the water and most of the milk solids are removed, but it is a milk product and is labelled as one. Curds are coagulated milk solids. Paneer and quark are fresh cheeses that appear untranslated on South Asian and central European packaging.

Recaldent is the trade name for CPP-ACP, a peptide derived from milk casein, used in some tooth-remineralising gums and dental products.

How the label is worded where you are

The EU and UK systems require milk to be emphasised inside the ingredient list, which means casein, whey and lactose cannot appear as bare technical terms — the milk origin has to be visible, usually as bold text. Two milk-derived items are named exceptions: whey used to make distillates and agricultural ethyl alcohol, and lactitol. Those are exempt from allergen declaration altogether, not merely from the bolding, so they need not appear as milk anywhere on the label. In the United States the plain word milk must appear, either bracketed after the ingredient or in a “Contains” line, which makes casein and whey much easier to catch. Elsewhere, you may get only the ingredient name with no emphasis and no summary line.

Cross-contamination and “may contain”

Milk is one of the most common precautionary warnings on the shelf, because dairy runs on shared equipment: the same line makes a milk chocolate bar and a dark one, the same bakery mixer handles brioche and a plain loaf. Wording like “may contain milk” or “made on equipment that also processes milk” is voluntary and unstandardised, and one phrase is not legally safer than another. Its absence is not proof that no milk was in contact — and loose items from a bakery or deli counter come with no ingredient list at all. PNut reports any such warning as May contain rather than resolving it one way or the other, and what “may contain traces” actually means goes through how those warnings are decided.

Reading a milk label abroad

The base word is easy — lait, leche, Milch, 牛奶 — and it is usually easy to spot. The derivatives are the problem, because lactosérum, Molke, siero di latte and 乳清 all mean whey and none of them look like the word for milk. The table below gives both, so you are looking for two patterns rather than one — and reading a label in a language you don’t speak covers the part around them: which paragraph is the ingredient list, and what order it is in.

How PNut flags milk

Scan the barcode and PNut looks up the product’s published ingredient list; photograph the ingredient panel and it reads the text off the label instead, in any of 40+ languages. It checks for milk and every derivative on this page, then gives one of four verdicts — Safe, Contains allergen, May contain, or Unknown when the label cannot be read. An unreadable label returns Unknown rather than a guess.