'May contain' is a real warning. 'Free-from' is a promise.

Two kinds of allergen wording

The ingredients list and its emphasised allergens are the mandatory layer: the fourteen declarable allergens have to be named and emphasised whenever they are deliberate ingredients. The 14 allergens guide covers that list, and the ingredients-list guide covers how the emphasis works. Source: FSA allergen labelling technical guidance (opens in a new tab).

Everything else — "may contain nuts", "milk-free", "gluten-free" — is voluntary wording about accidental presence or deliberate promise. Voluntary does not mean loose: the FSA's technical guidance treats precautionary allergen labelling as information that must come out of a genuine risk assessment, and using it carelessly can itself mislead — which food law does not permit. Source: FSA allergen labelling technical guidance (opens in a new tab).

So the phrases sort into two jobs. One job is a warning — the risk assessment found a route it could not close. The other is a guarantee — the maker is standing behind a claim of absence. Neither is noise, but only one of them is a promise.

'May contain': a real risk, used sparingly by rule

Precautionary allergen labelling — PAL — is the technical name for "may contain milk" or "not suitable for people with a nut allergy". GOV.UK's labelling pages are specific about when it belongs: where a cross-contamination risk has been identified and cannot be controlled. It is a last resort after managing the risk, not a substitute for hygiene. Source: GOV.UK on precautionary allergen labelling (opens in a new tab).

The wording has rules of its own. It should name the specific allergen — a blanket "may contain allergens" is not the sanctioned approach — and it should not sit next to a "free-from" claim for the same allergen, because warning and guarantee cannot both be true. Source: GOV.UK on precautionary allergen labelling (opens in a new tab).

For the reader, that framing makes the phrase worth taking at full value: a real "may contain" means someone's risk assessment found a route they could not close. If the allergen on the label is yours, the question goes to the business — not to a guess about how likely it is.

'Free-from': a claim the maker must be able to back

A free-from claim is the opposite posture — the maker is saying the food is suitable for people with that food hypersensitivity. The FSA's technical guidance calls it a guarantee, and the allergen guidance for businesses spells out what holds it up: strict controls to eliminate the risk of cross-contamination, not just an ingredient left out of the recipe. Source: FSA allergen labelling technical guidance (opens in a new tab) Source: FSA allergen guidance for businesses (opens in a new tab).

Two consequences follow. A maker cannot hedge the claim with a "may contain" for the same allergen — the guidance rules the combination out. And the guarantee is narrower than it looks: a "milk-free" label says nothing about nuts or gluten; each claim covers the allergen it names. Source: FSA allergen labelling technical guidance (opens in a new tab).

When the control cannot be guaranteed, the honest label is the warning, not the promise — the businesses' guidance uses flour as its worked example: where wheat flour is handled and the cross-contamination risk cannot be removed by segregation in time and space, the right move is telling the customer, not claiming "wheat-free". Source: FSA allergen guidance for businesses (opens in a new tab).

'Gluten-free' and the 20 ppm line

"Gluten-free" is the one voluntary phrase with a hard number behind it. Under the rules applying in the UK — and the EU regulation they derive from — only foods containing 20 parts per million (20 mg/kg) of gluten or less, as sold, may carry the claim. Coeliac UK explains the figure is set at a level considered tolerable for people with coeliac disease, and the labelling has been mandatory-standard since January 2012. Source: Coeliac UK on gluten-free law (opens in a new tab) Source: Regulation (EU) 2014/828 (opens in a new tab).

A second tier exists beside it: "very low gluten" covers foods between 21 and 100 ppm, made for specialist substitute products using specially processed gluten-free wheat starch. Coeliac UK notes products labelled this way are found in some European markets rather than on UK shelves — worth knowing if you shop abroad. Source: Coeliac UK on gluten-free law (opens in a new tab).

One boundary is easy to miss: the threshold answers the coeliac question — gluten content — not the wheat-allergy question. Gluten-free wheat starch is still wheat in the ingredients sense and must appear in the list; someone with a wheat allergy reads the ingredients as well as the claim. Rules differ outside the UK and EU too, so the number travels less reliably than the phrase. Source: Coeliac UK on gluten-free law (opens in a new tab).

Vegan labels are not allergen labels

A "vegan" claim describes ingredients by choice, not cross-contact by risk — the FSA's technical guidance is explicit that it communicates different information aimed at different consumers. The businesses' guidance gives the practical version: customers may assume a vegan meal is free from animal-derived allergens like egg, milk or fish, but low-level cross-contamination can still occur in production, which is why a vegan label can lawfully stand beside a "may contain milk". Source: FSA allergen labelling technical guidance (opens in a new tab) Source: FSA allergen guidance for businesses (opens in a new tab).

So the three wordings each answer their own question: "may contain" = a risk we could not close; "free-from" = a guarantee we must be able to back; "gluten-free" = 20 ppm or less by rule. "Vegan" answers a different question entirely — what the recipe intends, not what the factory can exclude.

When the wording is ambiguous

If the label leaves you unsure — a vague "produced in a factory" line, a free-from claim that seems to contradict a warning, or no wording at all — the answer is not to average the signals. Ask the manufacturer or the business; PAL can be communicated on signs and verbally as well as on packs. If you have the allergy or coeliac disease and the ambiguity survives the asking, the safe answer is not eating it until someone can say more. Source: GOV.UK on precautionary allergen labelling (opens in a new tab).

And the standing boundary: a photograph of the pack — or of the dish — cannot read the label or the risk assessment behind it. A lookup can name the food; the words on the pack and the people who made it are the only reliable source for what is or is not inside. Asking the right questions is the companion skill for eating out.