"May contain": when to use it — and when not to

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.

Unlike the ingredient declaration itself — which is mandatory and covered by our guides to the 14 allergens and PPDS labelling — a may-contain statement is voluntary. The legal constraint is that food information must not mislead: a warning should reflect a real, assessed risk, and the absence of a warning implies you've controlled the risk.

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 — battered fish and chips from the same oil means fish traces in the chips. Classic, legitimate may-contain.
• Airborne flour — a bakery dusting workbenches can't call anything in the room gluten-free-safe.
• Shared slicers and scoops — deli meat/cheese slicers, ice-cream scoops moving between tubs.
• Your suppliers' own warnings — if your chocolate says "may contain peanuts", your brownie inherits that warning. Check every label, every reorder.
• Loose nuts and seeds in the kitchen — notoriously mobile; walnut fragments turn up everywhere.

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, that's the M state — one click in the free builder, printed with your dated matrix.
• On PPDS labels, it's a "May contain:" line after the ingredients list. AllergenKit Pro derives it automatically from the may-contain flags on your ingredients, so labels and matrix always agree.
• 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.