Guide · Precautionary labelling
"May contain": when to use it — and when not to
Precautionary allergen labelling is voluntary, widely misused, and quietly dangerous in both directions: missing when there's a real risk, slapped on everything when there isn't. Here's how to get it right.
What "may contain" actually means
"May contain nuts", "made in a kitchen that handles sesame", "not suitable for milk allergy sufferers" — these are all precautionary allergen labels (PAL). They don't declare an ingredient; they warn about possible cross-contamination (allergen experts say "cross-contact"): allergen traces that could get into the food unintentionally from shared equipment, surfaces, storage or airborne dust.
A "may contain" statement is generally voluntary; it is different from declaring an allergen that is an ingredient. PPDS food needs an ingredients list with allergenic ingredients emphasised, while non-prepacked food needs allergen information but not a full ingredients list. Precautionary wording should reflect a real risk found through assessment, not serve as blanket cover. See the FSA's PPDS guidance.
When "may contain" is the right call
Use it when, after taking sensible precautions, a genuine risk remains that you cannot practically eliminate:
- Shared fryers — shared oil can transfer allergens. Assess the ingredients, process and remaining risk before deciding what warning is needed.
- Airborne flour — assess whether airborne flour can reach other foods; a gluten-free claim needs its own evidence and controls.
- Shared slicers and scoops — deli meat/cheese slicers, ice-cream scoops moving between tubs.
- Your suppliers' own warnings — check any "may contain peanuts" advice on your chocolate when assessing the finished brownie, and keep supplier information current.
- Loose nuts and seeds in the kitchen — assess handling, storage and cleaning to prevent fragments reaching other foods.
Be specific: "May contain: peanuts, sesame" tells an allergic customer something they can act on. "May contain traces of allergens" tells them nothing except that you haven't thought about it.
When it's the wrong call
- As a substitute for cleaning up your act. If separate boards, washed hands and covered storage would remove the risk, remove the risk — don't label around it. Inspectors treat PAL-instead-of-precautions as a control failure.
- Blanket "may contain all 14" on everything. It reads as legal cover, strips customers of usable choice, and can itself be challenged as misleading. It also collapses the moment one warning is real: nobody can tell which.
- For allergens that are actually in the recipe. If the pesto contains cashews, cashews go in the ingredients list as a contains — never downgraded to a may-contain.
Recording it properly
Cross-contact risks belong in the same paperwork as your ingredient allergens, or staff will never relay them:
- On your allergen matrix, select the M state in the free builder to include the warning in your dated matrix.
- On PPDS labels, a justified "May contain:" line can follow the ingredients list. AllergenKit Pro carries forward may-contain flags you enter; review the finished-food risk and wording before use.
- Revisit the assessment when anything changes — new supplier, new equipment, new layout. A may-contain that nobody has re-checked in a year is guesswork wearing a label.