What "may contain traces" actually means

“May contain traces of nuts” is the most-read sentence in food labelling and one of the least understood. People treat it as a measurement, or as a legal grade of risk, or as a manufacturer being careful. It is none of those. In most of the world it is a voluntary sentence, written by the manufacturer, in wording of their choosing, about the factory rather than about the recipe — and knowing that changes how you read it.

It describes the building, not the ingredients

The ingredient list tells you what was deliberately put in. A precautionary statement tells you that something else was in the same room: on a shared mixer, a shared conveyor, a shared fryer or in the air. Flour and milk powder are dusts and travel; nut and sesame fragments survive cleaning cycles; the same line runs a plain biscuit at nine in the morning and a hazelnut one at two in the afternoon.

Those are real risks, and for some products the warning is doing honest work. But it is describing a possibility, not a quantity. Unless the manufacturer is working to a scheme that defines what the phrase means — and almost none are — the sentence does not tell you whether the risk is one contaminated packet in a hundred or one in ten million.

It is voluntary almost everywhere

This is the part that surprises people. The mandatory allergen rules apply to what the product is made from. In the EU and the UK, Reg. (EU) No 1169/2011 — the FIC regulation — requires the Annex II allergens to be declared and emphasised inside the ingredient list, under Article 21. In the US, FALCPA requires the plain-English name of each major allergen, either in the list or in a “Contains” statement, with sesame added to those majors by the FASTER Act from 1 January 2023.

None of that covers cross-contamination. There is no instrument in the EU, the UK or the US that says when a “may contain” line must appear, or what it must say, or what level of contamination triggers it. The general rule — that food information must not be misleading — still applies, but that is a long way from a standard. So two factories with identical processes can label differently, and the same factory can label two of its own products differently, without either of them breaking a rule.

The practical consequence is that the presence of a warning tells you something about the manufacturer’s legal caution as well as something about their production line, and you cannot tell from the label which of the two you are looking at.

The wording ladder is not a ladder

There is a widespread belief in a hierarchy — that “may contain” is worse than “made in a factory that also handles”, or that “not suitable for” is the serious one. It is a reasonable thing to infer from the language. It is not true. None of these phrases is defined in law, none ranks above another, and the difference between them usually reflects who drafted the packaging copy rather than any measured difference in risk:

• may contain traces of X
• may contain X
• made in a factory that also handles X
• made on equipment that also processes X
• not suitable for people with an X allergy
• cannot guarantee X free

Treat all of them as the same signal. If you would avoid a product that said “not suitable for”, the “may contain traces” version deserves the same decision, because nothing on the label tells you they are different.

The absence of a warning is not an assurance

This is the uncomfortable half. Because precautionary labelling is voluntary, a packet with no warning may be from a dedicated line, or may be from a shared one belonging to a company that has decided not to label it. Silence is not a clean result; it is silence. The manufacturer is the only one who can tell you which it is, and for a severe allergy that phone call or email is the only thing that actually answers the question.

The same logic applies with more force to food that carries no ingredient list at all — bakery trays, deli counters, bulk bins, pick-and-mix. There is no warning to be absent, and shared scoops and shared oil are the norm rather than the exception.

VITAL, the exception

One scheme does what everybody assumes the warnings already do. VITAL — Voluntary Incidental Trace Allergen Labelling, developed by the Allergen Bureau in Australia and New Zealand — is a voluntary, quantitative system. A manufacturer assesses how much of an allergen could realistically end up in a serving of the product and compares that against reference doses, and only where the assessment warrants it does a standardised precautionary statement go on the pack. The wording is fixed by the scheme rather than invented per product.

That makes a VITAL statement a different kind of object from an ordinary “may contain”: it is the output of an assessment rather than a disclaimer. It is worth knowing it exists, both because you will meet it on Australasian packaging and because it shows what is missing from the voluntary free-for-all everywhere else. It is still voluntary, though, and its absence from a pack means only that the maker did not use the scheme.

Your threshold is yours to set

How you act on a may-contain warning is not a labelling question, and there is no single right answer to it. It depends on how you react, on the food, and on the conversation you have had with your own clinician. Some people avoid every precautionary label; some accept them on products where shared handling is unlikely and refuse them on the categories where it is routine.

What is worth doing is deciding in advance rather than in the aisle, and deciding by category. Chocolate and confectionery, biscuits and cereal bars, ice cream and bakery goods are the aisles where shared lines are standard, which is why peanuts and tree nuts carry warnings so often. Flour dust puts bakery and cereal products in the same position for wheat. Knowing that a warning is expected in a category does not make it safer — it just means its presence carries even less information than usual.

How PNut reports it

PNut keeps this distinction rather than flattening it. An allergen in the ingredient list is Contains allergen. Precautionary wording — in any of its phrasings, in any of 40+ languages — is May contain, a separate verdict, so you can apply your own rule to it instead of having ours applied for you. A label with no readable ingredients is Unknown, not Safe. How it works shows where each verdict comes from.

And the honest caveat: PNut reads what the label says. It cannot see inside the factory, and it cannot turn a missing warning into a guarantee. Nothing on a label can.