July 30, 2026

What 'May Contain Traces' Actually Means

“May contain traces of nuts” is one of the most confusing sentences in food labelling, because it is doing something quite different from the rest of the label.

It is voluntary, and it is not standardised

The ingredient list is regulated. Precautionary allergen labelling — “may contain”, “made in a factory that also handles”, “not suitable for” — largely is not, in the EU or the UK.

Two consequences follow, and they are the whole story:

1. The wording does not encode severity. “May contain” and “made in a factory that also processes” are not a scale. Different manufacturers use different phrases for identical situations.
2. Its absence proves nothing. A product with no precautionary statement has not been tested and cleared. It may simply be a manufacturer that does not use the labels.

That second point is the one people find genuinely surprising. Silence is not a negative result.

What it usually means in practice

Shared equipment or a shared production line. Chocolate with nuts runs, then plain chocolate runs after a clean. The clean is usually thorough. “Usually” is where your risk tolerance lives.

Some manufacturers apply the label broadly as legal cover. Others test and only label when they find something. From outside, the two are indistinguishable.

How to decide

There is no correct answer here, only an informed one — and it is a conversation for your allergist, not a blog.

The factors that usually matter:

• Your reaction threshold. Some people react to trace amounts; many do not.
• Your history. Reactions to “may contain” products are meaningful evidence.
• The setting. Trying a borderline product at home is different from doing it two hours from a hospital.
• The allergen. Peanut and tree nut cross-contact is generally treated more cautiously than most.

Plenty of people with allergies eat “may contain” products routinely. Plenty avoid them entirely. Both are reasonable positions from different starting points.

Why an app should keep them separate

This is why Allervibe shows traces in their own section, distinct from actual ingredients. Merging them would either produce constant false alarms or bury a real ingredient among precautionary noise.

You get “Contains your allergens” and “May contain (traces)” as separate answers, and you decide what to do with the second one.

Where the data comes from

Product databases record trace declarations only when the manufacturer prints them, so the same limitation applies: absent data is not the same as a cleared product. Any scanner, ours included, is doing a fast first pass. The package is the authority.

For eating out

Restaurants have no equivalent of a “may contain” label, and shared fryers and grills are the same class of risk. That is what the cross-contact line on a printed allergy card is asking about — and it is the line most worth pointing at directly.