“May Contain” Labels

Three words that appear on more food packaging than most people realise, and that confuse nearly every newly diagnosed coeliac. “May contain gluten,” “may contain traces of wheat,” “produced in a facility that also handles wheat.” What do these phrases actually mean, and should you eat the product or not?

Understanding Precautionary Allergen Labels

“May contain” statements are precautionary allergen labels (PALs). They are voluntary: manufacturers are not legally required to include them. They appear when a manufacturer has assessed that cross-contamination is possible in their facility, typically because gluten-containing products are made on the same production lines or in the same factory.

What they don’t tell you is how likely the contamination is, or how much gluten might be present. “May contain” could mean a thorough clean happens between production runs and contamination is a remote possibility. It could also mean the line runs wheat-based products immediately before yours. The label doesn’t distinguish between these scenarios.

The gluten-free standard in the EU, UK and USA is 20 parts per million (ppm) or less (under 20 in the US); Australia and New Zealand require no detectable gluten. A product labelled gluten-free must meet this threshold by law, whether or not it is certified. A “may contain” warning is a separate, voluntary note, and in the EU, UK, US and Canada a product can lawfully carry both.

What the label is and isn’t: a “may contain” line is voluntary and unregulated, and in the EU it carries no legal weight. It is not a measured result, so it tells you nothing about whether gluten is actually present or at what level. The reliable signal is the “gluten-free” claim, which is a tested standard (20 ppm or less in the EU and UK, under 20 ppm in the US, no detectable gluten in Australia and New Zealand). What to do with one depends on where you shop. In the EU, a “may contain” line is not an ingredient, so the ingredient list and a gluten-free claim decide, and a bare “may contain” line on its own doesn’t make a product unsuitable. In the UK, Coeliac UK advises not eating a product that has no gluten-free claim but carries a “may contain” statement for cereals containing gluten. A product labelled gluten-free still meets the 20 ppm limit there even if it also says “may contain wheat”. In Canada, Celiac Canada recommends avoiding products with a “may contain” statement for wheat, barley, rye, regular oats or triticale.

Non-coeliac gluten sensitivity (NCGS): People with NCGS rather than coeliac disease have more flexibility here. Since the harm mechanism is different (no autoimmune gut damage), the threshold for individual tolerance can be higher and is self-assessed through symptoms rather than biopsy.

Where “may contain” labels become especially frustrating is on naturally gluten-free staples (plain rice crackers, nuts, dried fruit) where the label reflects factory risk rather than any ingredient issue. In these cases, finding a brand with the same product labelled gluten-free is usually straightforward.

What This Means for You

Treat the “gluten-free” claim as your strongest signal. A precautionary “may contain” warning is voluntary and tells you nothing measurable. In the EU, where a product carries a valid gluten-free claim, or its ingredient list has no gluten-containing cereal, that precautionary line on its own is no reason to put it back. In the UK, leave a product on the shelf if it has no gluten-free claim and a “may contain” line for a cereal containing gluten, as Coeliac UK advises; in Canada, Celiac Canada recommends avoiding products with a “may contain” statement for wheat, barley, rye, regular oats or triticale. Reserve real caution for products that carry no gluten-free claim at all.

Related in the Coeliac Alphabet: Food Labels · Parts Per Million · Label Reading FAQ · back to the full A–Z.