May contain vs not suitable for: UK allergen labels
Two ready meals sit on the same chiller shelf. Both are made in factories that also process sesame. One label says "may contain sesame." The other says "not suitable for someone with a sesame allergy." Both are legal. Neither technical manager can point to a rule that told them which one to pick, because there isn't one.
That gap matters more than it used to. Since the Codex Alimentarius Commission adopted the first international precautionary allergen labelling (PAL) standard in July 2026, UK teams have started tightening up when they use a PAL statement at all. Fewer blanket warnings, more documented risk assessments. What most haven't touched yet is which words the assessment leads to. That's the harder half of the same decision, and it's the one nobody has written a straight answer to yet.
What the FSA actually permits, and what it leaves open
FSA guidance, in place since December 2017 and still the current position, allows exactly two forms of precautionary wording: "may contain X" and "not suitable for someone with an X allergy." Generic statements like "may contain allergens" or "produced in a factory that handles nuts" are flagged as potentially misleading, because they don't reflect a specific, assessed risk.
The guidance doesn't rank the two permitted options. It doesn't say "use 'not suitable for' when the risk is higher," and it gives no threshold that moves a product from one wording to the other. Codex's July 2026 standard doesn't fill that gap either: it sets out when a PAL should appear at all, using ED05, the dose at which 5% of allergic people would be likely to react, as the reference point. It says nothing about which of the two permitted phrases to use once that threshold is crossed.
We checked the consultancies who write about this for a living. Campden BRI's own position is blunt: "there is no consensus in the food industry about when to use precautionary allergen labelling, other than the guidance to use when the risk cannot be removed." Ashbury's guidance lists both wordings and stops there too. So the two-meal example above isn't a labelling error. It's what happens when two different technical teams make the same real decision without a framework.
Why "may contain" became the default, and why that's a problem
Most teams reach for "may contain" first, for a reason that has nothing to do with risk: it's the older, more familiar phrase, it's already in the artwork template, and it reads less alarming on pack. Teams tend to reach for "not suitable for" only when someone, usually late in sign-off, decides the first option doesn't feel strong enough for a specific ingredient.
That's a wording choice driven by comfort, not by the underlying risk assessment. It's also exactly the pattern the Codex standard is trying to close off on the whether-to-label side. There's no reason the which-wording side should stay less disciplined.
A decision framework that holds up
Neither the FSA nor Codex will draw this line for you, so here's the logic we'd defend if a retailer technical team or an allergic consumer asked us to justify it. It's not a legal requirement. It's a defensible, documented position, which is what actually protects you if a claim is ever challenged.
Use "may contain X" when your risk assessment shows a quantified, low-probability, trace-level risk that you can't fully eliminate through cleaning and scheduling, but that sits close to the threshold where a PAL is needed at all. Think: shared equipment with a validated clean-down that gets you close to the ED05 reference dose but not reliably under it, on a low-frequency changeover. The phrase communicates "possible, assessed, and unlikely," which matches the risk.
Use "not suitable for someone with an X allergy" when the residual risk is real, harder to quantify precisely, and closer to structural rather than incidental: shared lines without full segregation, an ingredient supplied with its own upstream PAL you can't verify, or a process where allergen removal can't be validated to a specific dose. This phrase reads as a firmer exclusion, and it should, because the underlying uncertainty is bigger.
Never let the two coexist for the same allergen on the same product. If your risk assessment produces both a quantified low-probability finding and a structural, unquantifiable one for the same allergen, that's a sign the assessment itself needs redoing, not a reason to stack both statements.
Match the wording to what changes in your process, not to what the last product did. If you switch to a validated allergen-free change-over on a line that previously ran nuts, that's grounds to move from "not suitable for" to "may contain," or to drop the PAL altogether. Re-labelling on evidence is a sign of a live risk assessment. Copying last year's artwork is a sign the assessment stopped happening.
One reference point worth knowing even though it isn't UK law: the Australian and New Zealand food industry's VITAL programme moved to the same ED05 reference dose in its VITAL 4.0 update (August 2024), dropping the more conservative ED01 threshold it used to run on. The Allergen Bureau's own reasoning was blunt: the stricter ED01 threshold "did not meaningfully reduce the health risks to food-allergic individuals," it just meant more products carrying a PAL for no real safety gain. VITAL still isn't adopted in the UK, but it now runs on the same ED05 logic as the Codex standard, which makes it a reasonable proxy framework if your team wants a documented, internationally consistent threshold to work from ahead of any UK-specific one arriving.
Also worth checking: IGD, working with Tesco, Sainsbury's, ASDA, Bakkavor, Greggs, and several other major UK manufacturers and retailers, published a standardised allergen risk assessment template in September 2025. It's registration-gated, but it's a useful benchmark to check your own process against, or a starting point if you're building one from scratch.
What this means for a food team
Audit your current PAL wording the same way you'd audit whether you need a PAL at all. For every "may contain" and every "not suitable for" on your range, ask whether the choice traces back to an assessed risk level, or just to whoever built the artwork template first.
Standardise the criteria before your next NPD brief, not after a customer complaint. A one-page internal rule, even a simple one like "'not suitable for' when residual risk is structural and unquantifiable, 'may contain' when it's assessed and low-probability," gives your technical team a defensible answer the next time a retailer or an allergic customer asks why a label says what it says.
Check whether your retailers already have a house preference. Some technical teams specify wording in their supplier compliance briefs. If yours does, that overrides the framework above, but it's still worth knowing why the retailer chose it.
Companion piece: May contain: when to use precautionary allergen labels, and when you shouldn't covers the whether-to-label decision this post assumes as its starting point.
Frequently asked questions
When should a manufacturer use a "may contain" warning?
When a documented risk assessment shows a real but low-probability, assessed trace-level risk of allergen cross-contact that can't be fully removed through cleaning or scheduling. It should never be added without that assessment behind it.
What's the difference between "may contain" and "not suitable for" allergen labels?
Legally, nothing: FSA guidance permits both and doesn't rank them. In practice, "may contain" reads as a lower-probability, assessed trace risk, while "not suitable for" reads as a firmer exclusion, better suited to structural or harder-to-quantify cross-contact risk. Neither reading is written into UK law; it's the practical convention worth adopting in the absence of one.
Is "not suitable for" a stronger warning than "may contain"?
Most consumers and technical teams read it that way, but the FSA doesn't formally rank either as stronger. Whichever wording you use should be backed by a documented risk assessment that justifies the choice itself, not just the decision to label at all.
Can I use both "may contain" and "not suitable for" on the same product?
Not for the same allergen. If your risk assessment produces a mixed result for one allergen, that's a signal to redo the assessment, not to stack both statements on pack.
Does the FSA recommend one wording over the other?
No. FSA guidance, current since December 2017, lists both phrasings as acceptable and gives no criteria for choosing between them. The choice is left to the food business's own risk assessment.
Do retailers have their own rules on PAL wording?
Some do, as part of their supplier technical or compliance briefs. Always check your retailer's specification before applying a standard framework, since a retailer requirement will sit above general industry practice.
Want to check every SKU's PAL wording against its risk category without opening a spreadsheet? Canoli does exactly that, tracking allergen declarations against your recipe data so it's a filtered report, not a fresh project. Try it here.