“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 most jurisdictions (EU, UK, USA, Australia) is under 20 parts per million (ppm). Products that are certified gluten-free have been tested to verify they meet this threshold. Products with a “may contain” warning have not been through that verification — or have been assessed as too high-risk to carry a certified label.

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 of under 20ppm. Historically some coeliac organisations advised avoiding all “may contain” products; in practice, where a product carries a valid gluten-free claim — or is a naturally gluten-free whole food — a bare “may contain” line can generally be disregarded.

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 that is certified gluten-free is usually straightforward.

What This Means for You

Treat the “gluten-free” claim as your signal, not the “may contain” line. A precautionary “may contain” warning is voluntary and tells you nothing measurable; where a product carries a valid gluten-free claim, or is a naturally gluten-free whole food, that precautionary line can generally be disregarded. 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.