Why "May Contain" Labels Are Unregulated and How to Assess Their Actual Risk
If you or someone in your family lives with a food allergy, you will have encountered the phrase "may contain traces of nuts" — or similar wording — on countless food packages. These labels appear reassuringly cautious, but the reality is that precautionary allergen labelling (PAL) in the UK remains entirely voluntary and unregulated. There is no legal standard governing when manufacturers must use them, what they mean, or how much of an allergen is actually present. Understanding this gap — and knowing how allergy blood testing may help you assess your personal risk — is an important part of proactive health management.
What Does "May Contain" Actually Mean?
Precautionary allergen labelling refers to advisory statements placed voluntarily on food packaging by manufacturers to indicate a possible — but unconfirmed — risk of cross-contamination with an allergenic ingredient during production. These are distinct from mandatory allergen declarations.
In simple terms, a "may contain" label means: this product was made in a facility or on equipment that also handles the named allergen, and we cannot guarantee complete separation. It does not confirm the allergen is present, nor does it indicate quantity.
The Regulatory Gap: Why "May Contain" Is Not Governed by Law
Mandatory vs. Precautionary Allergen Labelling: What the Law Actually Covers
Under UK food law — derived from EU Regulation 1169/2011 and retained post-Brexit — food businesses are legally required to declare the presence of 14 major allergens when they are used as intentional ingredients. These include peanuts, tree nuts, milk, eggs, wheat, soya, and others.
However, precautionary allergen labels are not covered by the same legal framework. There is currently no UK regulation that:
- Mandates when a manufacturer must apply a "may contain" statement
- Defines a minimum or maximum threshold of contamination before such a label is required
- Standardises the wording used across manufacturers or sectors
- Requires independent verification of contamination risk
This means two manufacturers with identical cross-contamination risks may make entirely different labelling decisions — one choosing to include a "may contain" warning, the other choosing to omit it.
| Labelling Type | Legal Requirement | Standardised Wording | Threshold Defined | Verified by Regulator |
|---|---|---|---|---|
| Mandatory allergen declaration | ✅ Yes | ✅ Yes | ✅ Yes (intentional use) | ✅ Yes |
| Precautionary "may contain" label | ❌ No | ❌ No | ❌ No | ❌ No |
| "Free from" claims | Partial guidance | Partial | ❌ No legally binding UK threshold | ❌ No |
Practical Insight: Because "may contain" labelling is self-regulated by manufacturers, the same phrase can mean very different levels of actual risk — making it unreliable as a sole decision-making tool for people with known food allergies.
Why This Creates Real Confusion for Allergy-Conscious Consumers
The unregulated nature of precautionary labelling has created a significant challenge for the estimated 2 million people in the UK living with a diagnosed food allergy, and a broader group managing food intolerances or sensitivities.
Common problems include:
- Over-labelling: Many manufacturers apply "may contain" warnings even when contamination risk is negligible, reducing product choice unnecessarily
- Under-labelling: Some products carry a genuine cross-contamination risk but display no advisory warning
- Inconsistent terminology: Phrases such as "may contain," "not suitable for," "made in a factory with," and "produced on shared equipment" are all used interchangeably with no formal distinction
- No allergen quantity indication: Even if a product does contain trace amounts, there is no guidance on how much — which matters significantly depending on an individual's sensitivity threshold
For Londoners and those across the UK navigating busy lifestyles, eating out, travelling, or purchasing ready-prepared foods, this lack of standardisation can feel particularly difficult to manage.
How Allergy Blood Testing Can Help You Assess Your Personal Risk
Understanding whether a "may contain" label is relevant to you specifically begins with understanding your own immune response. Allergy blood testing — specifically specific IgE testing — measures the level of allergy antibodies your immune system produces in response to identified allergens.
What IgE Allergy Testing May Indicate
- Specific IgE levels can suggest the degree of immune sensitisation to a particular food allergen
- Higher IgE values may correlate with a lower threshold for reaction, though this is not absolute
- Identifying your specific allergen sensitisation profile can help contextualise labelling guidance
- Results may highlight sensitisations you were not previously aware of
At our nurse-led clinic, we provide professional allergen-specific blood testing and clear, comprehensible reporting — helping individuals better understand their sensitisation profile. We do not offer diagnosis, treatment, or prescriptions.
Practical Insight: A structured allergy screening report can give you a clearer picture of your sensitisation levels, supporting more informed conversations with a healthcare professional about what precautionary labels may mean for your personal situation.
Who Should Consider Allergy Blood Testing?
If you regularly manage food choices around allergen labels, you may find it useful to understand your sensitisation profile more clearly. Testing may be worth considering if you:
- Have previously experienced an unexplained adverse reaction to food
- Are unsure whether your sensitivity is mild, moderate, or higher
- Want to understand your immune response to specific allergens more clearly
- Are managing a family member's food allergy and wish to understand the full picture
- Feel uncertain about how to interpret precautionary labels in relation to your health
Our food allergy blood testing service is available to adults and can be arranged without a GP referral.
How Often Should Allergy Testing Be Repeated?
Allergen sensitisation can change over time. Sensitivity levels may increase or decrease depending on exposure, immune system changes, age, or environmental factors. As a general consideration:
- Initial testing is appropriate when a new concern is identified or symptoms arise
- Follow-up testing may be considered after 12–24 months, or sooner if dietary changes or new reactions occur
- Those managing multiple food allergies may benefit from periodic screening to ensure their sensitisation profile remains current
We recommend discussing the frequency of testing with an appropriate healthcare professional based on your individual history.
Understanding Your Results: What They Can and Cannot Tell You
Allergy blood test results report specific IgE levels in kilounits per litre (kU/L). These values are typically categorised from Class 0 (undetectable) through to Class 6 (very high sensitisation).
What results may suggest:
- Whether sensitisation to a specific allergen is present
- The relative level of immune response detected at the time of testing
- Which allergens your immune system recognises
What results do not confirm:
- Whether a clinical allergic reaction will occur upon exposure
- The exact dose of allergen that would trigger a response
- Whether "may contain" products are safe for you to consume
Interpreting results in context requires appropriate clinical input. Our comprehensive allergy screening packages provide detailed reports that you can share and discuss with a qualified healthcare professional.
Local Context: Managing Food Allergies in London
London's diverse food landscape — from international restaurants and street food markets to supermarket meal deals and workplace catering — presents particular challenges for those navigating allergen labelling. With a high concentration of food businesses and a complex supply chain, precautionary labels are especially common in urban retail environments.
Understanding your sensitisation profile through professional allergy blood testing in London may help you make more informed, evidence-supported decisions about the foods and environments you encounter daily. Whether you are shopping in a major supermarket or dining at an independent restaurant, having a clearer picture of your personal sensitisation levels can support more confident — and safer — choices.
Frequently Asked Questions
1. Are "may contain" labels legally required in the UK?
No. Precautionary allergen labels such as "may contain" are entirely voluntary in the UK. There is no legal requirement for manufacturers to include them, and no regulated standard governing the wording, threshold, or verification of such statements. Mandatory labelling applies only to allergens used as intentional ingredients.
2. Does "may contain nuts" mean there are definitely nuts in the product?
Not necessarily. It indicates a potential risk of cross-contamination during production, but it does not confirm that allergen is present. The label is precautionary, not confirmatory. The actual level of contamination — if any — is not disclosed on the label.
3. Can allergy blood testing tell me if a "may contain" product is safe for me?
Allergy blood testing can help identify your level of sensitisation to specific allergens, which may contextualise your risk. However, it cannot definitively confirm whether a specific product is safe to consume. Results should be discussed with an appropriate healthcare professional.
4. What is the difference between a food allergy and a food intolerance?
A food allergy involves an immune system response — typically IgE-mediated — that can cause symptoms ranging from mild to severe. A food intolerance generally does not involve the immune system and tends to produce digestive symptoms. Blood testing can help distinguish between these using different panels.
5. Is allergy blood testing available without a GP referral in the UK?
Yes. At our nurse-led clinic in London, allergy blood testing is available without a GP referral. We provide testing and reporting only. We do not offer diagnosis, prescriptions, or treatment services.
6. What allergens can be tested through a blood test?
Specific IgE blood testing can screen for a wide range of food and environmental allergens, including peanuts, tree nuts, milk, eggs, wheat, soya, shellfish, and many others. Panels vary, and your testing can be tailored to your reported concerns.
7. How long does it take to get allergy blood test results?
Results are typically available within a few working days, depending on the panel requested. Our clinic provides a detailed written report with your results.
8. Can children be tested for food allergies at your clinic?
Our clinic primarily provides adult testing services. For paediatric allergy concerns, it is advisable to consult with an appropriate healthcare professional who specialises in children's health.
9. What should I do if I suspect I've had an allergic reaction to food?
If you experience symptoms that may suggest a severe allergic reaction — such as swelling, breathing difficulty, or collapse — seek urgent medical care immediately. For less acute concerns, noting your symptoms and discussing them with a healthcare professional is advised before pursuing testing.
10. How is precautionary allergen labelling expected to change in the UK?
The Food Standards Agency (FSA) has been actively reviewing PAL regulations and has published position papers supporting movement towards a standardised, legally defined framework. However, as of 2026, binding regulations have not yet been implemented. Monitoring FSA announcements is recommended for the latest guidance.
A Note on Our Approach
At Allergy Clinic, we are a nurse-led health screening service providing professional allergy blood testing and detailed reporting for adults in London and across the UK. Our team is committed to providing clear, evidence-informed information and accurate laboratory results to help you understand your sensitisation profile. We do not offer medical diagnosis, prescriptions, treatment plans, or specialist medical opinions. All clinical decisions and interpretations of your results should be made in consultation with an appropriate healthcare professional.
Take a Proactive Step Towards Clearer Information
If you are regularly navigating food allergen labels and want a clearer picture of your specific sensitisation profile, consider booking an allergy blood test with our experienced team. Knowledge of your immune response to key allergens may support more informed, confident decision-making — particularly when precautionary labels leave more questions than answers.
Visit www.allergyclinic.co.uk to explore our allergy testing options and take a proactive step in understanding your health.
Disclaimer
This article is intended for educational and informational purposes only. It does not constitute medical advice, diagnosis, or a treatment plan. The content should not be used as a substitute for professional medical guidance. If you have concerns about food allergies, allergic reactions, or your health more broadly, you should seek advice from an appropriate and qualified healthcare professional. Individual results from allergy blood testing must be interpreted in the context of your full clinical history by a suitable professional. No outcomes are guaranteed. This article complies with UK GMC advertising guidance, CQC patient communication standards, and ASA editorial guidelines.
