This is a short guide seeking to explain what is meant by precautionary allergen labelling (PAL) and why it is used, which aims to help healthcare professionals advising their food allergic patients how best to manage PAL and keep safe when shopping for food and eating out. 

Currently, there is no cure for food allergy, so avoidance of relevant allergens is a crucial component of effective management. 

In food manufacturing, and for foods sold loose (eg. catering establishments, markets and delicatessens, bakeries and fruit and vegetable sections of supermarkets), where food allergens are present along the food chain, there may be a risk of contamination from allergenic foods present within the environment. This contamination might occur at any point in the food chain. Food businesses have a legal responsibility through the Food Safety Act and General Food Law to ensure that foods they serve are safe for all consumers, including those with specific dietary needs. They are required do all they can to minimise the risk of cross-contamination. Where this is not possible, food businesses may place a statement on the packaging of a pre-packed food, a menu or other suitable location if the food is sold loose, warning that products might carry a risk of cross-contamination from a particular food allergen or allergens. The wording of this warning varies, but is commonly known as “may contain” labelling, precautionary allergen labelling (PAL), advisory labelling, alibi labelling or allergy warning labelling. For the purpose of this guide, we will use the term precautionary allergen labelling (PAL) to mean any sort of allergen warning on a food product.

What does the law say?

European food law (Consumers Regulation No. 1169/2011) requires 14 major allergens to be declared on the labelling of pre-packaged foods, and provide allergen information on request for food provided to consumers (e.g. from catering outlets or at catered events), where these allergens are present as an ingredient.

Many people believe PAL (relating to allergen that might be present due to contamination rather than as an intended ingredient) is required by law, but this is not the case. There is no legal requirement under EU allergen labelling laws for food manufacturers, retailers or caterers to warn of the possible risk of cross contamination from allergens.

If a product does not carry PAL, this might be because the food company has completed a thorough risk assessment and there is no risk of allergen contamination, or it might be because the company had not undertaken an assessment and any risk is unknown. So, just because a product does not have a PAL, does not mean there is no risk. Equally, products with PAL might have a significant risk of allergen cross-contamination or there might be no detectable allergen cross-contamination at all.

The Food Information for Consumers (FIC, Consumer Regulation 1169/2011), which became enforceable from 13th December 2014, includes the requirement that, where voluntary PAL is used, it must not mislead the consumer, be ambiguous or confusing for the consumer and, where appropriate, it should be based on relevant scientific data.

Key challenges for healthcare professionals

Healthcare professionals need to be aware of the psychosocial impact associated with food allergy in order to identify ‘red flags’ that might lead to adverse outcomes. Many food allergic patients ignore PAL and assume previous tolerance of products with PAL means their food allergy is mild, leading to increased risk-taking. Allergen cross-contamination is often inconsistent across different products with PAL and even across different batches of the same product. Uncertainties surrounding PAL, and the risk of a potential food-allergic reaction, can lead to anxiety and have a profound effect on the emotional and psychological wellbeing and quality-of-life for the patient and their family. In some cases, this anxiety can present at a clinical level and patients should be referred for appropriate treatment. A key challenge for healthcare professionals is assessing which patients are at high-risk for severe allergic reactions. Although food allergy-related deaths are rare, potentially life-threatening reactions do occur and can affect adversely patients' perceptions of risk as well as quality-of-life. Those who are high-risk of severe reactions might require different advice about avoidance and management to those at low risk. It is important to discuss with the individual or parent possible reasons why they think an adverse reaction has occurred in order to provide more personalised advice on future management.

Which patients may be at high risk?

Most severe allergic reactions occur when the allergen is added as an ingredient in a food product and a mistake is made by the consumer or the food provider. In some cases, a consumer might not make their food allergy known to the food provider or the food provider fails to provide proper information about a product. However, many food-allergic individuals ignore PAL. This might be because they perceive PAL as being used without good reason, e.g. they might have eaten the food before without reacting; they might be confused by the wording/ phrases used; they might feel their food choice is too restricted or they might have been advised that they can safely eat foods carrying PAL. They might also miss the warning entirely on packaging that is overcrowded with mandatory labelling information.

Predicting those who might be at high-risk of severe allergic reactions is challenging, but factors that should be considered include:

  • Age

Young food-allergic adults in their teens or 20s are at greatest risk of fatal food anaphylaxis compared with other age groups. Although this might in part be due to increased risk-taking amongst this age group, research suggests that other physiological factors might also cause this age group to be particularly vulnerable.

  • Health

Food allergic individuals exposed to their allergen(s) when they have an infection or are generally unwell might be at greater risk of a severe reaction. Specific health-related risk factors for severe reactions include: Asthma (poorly controlled asthma is a significant risk factor for severe reactions and the majority of food anaphylaxis-related deaths occur in individuals who have asthma) and cardiovascular disease and/ or antihypertensive medication.

  • Dose of allergen

While anaphylaxis can occur at very low allergen concentrations, most life-threatening reactions are caused by detectable amounts of allergen rather than traces. The relationship between dose sensitivity to allergen and severity is not clear, but available data show those who react to very low concentrations (e.g. milligram) are not necessarily at greater risk of severe reactions.

  • Skin contact and inhalation

There is little evidence to suggest that individuals who react through skin contact with their allergen(s) or inhalation of allergenic proteins where food is being cooked or served are at greater risk of severe reactions.

  • Previous reactions

The risk of a future severe reaction cannot be predicted from previous reactions. Although individuals who have experienced a severe reaction in the past might react severely in future, many with a history of anaphylaxis will experience non-anaphylactic reactions with future accidental exposures. About half of food allergy-related deaths occur in individuals who have previous had mild reactions.

  • Medication

Food-allergic individuals is taking certain types medication, such as non-steroidal anti-inflammatory drugs (NSAIDs) or medicines for indigestion, might be greater risk.

  • Food type

Any food can potentially cause anaphylaxis. However, the foods most commonly associated with severe reactions are peanut, tree nut, sesame, celeriac, seafood and cows' milk. In Southern Europe, lipid transfer proteins (LTPs) are potent allergens and have been known to cause severe reactions to foods such as peach. School-aged children and adults with cows' milk allergy might be at particular risk of severe reactions to accidental exposure. Many who are allergic to egg and cows' milk are able to tolerate these allergens in baked goods, such as cake or biscuits, but those who react to cows' milk and egg in baked foods are at greater risk of severe reactions.

  • Alcohol

Drinking alcohol can make risk-taking more likely and might, therefore, impair allergen avoidance and affect how quickly and effectively the individual responds to symptoms if they have a reaction. Alcohol might also increase the uptake of allergens from the gut.

  • Exercise

Exercising just before or after a reaction can cause the reaction to be more severe.

Allergy test results (allergy skin prick test and blood tests) are not useful or reliable indicators of reaction severity. A positive test indicates that an individual is sensitised to the allergen, but not how they will react following exposure if the test results are low. A high result implies the patient is more likely to react to that allergen, but it does not mean they will have a severe reaction.

Factors that may suggest a patient is at lower risk for severe allergic reactions include:

  • Tolerance of well-cooked and processed food (e.g. egg, milk)

Some food-allergic individuals can tolerate certain food allergens such as egg or cows' milk or foods containing these allergens, if they have been processed or cooked. Generally, people who can tolerate these foods are less likely to be at risk of a life-threatening reaction due to low-level accidental exposures.

Cooking other allergens, such as peanuts, tree nuts and fish, does not to reduce the likelihood of these allergens causing a reaction.

  • Pollen food allergy syndrome (PFAS)

For some people, their reactions to certain nuts, peanut, fruits or vegetables are thought to be due to pollen-related cross-sensitisation to plant-derived foods. They might have a lower risk of severe reactions. Typically, individuals with PFAS experience mild symptoms, such as itchiness and tingling around the lips and in the mouth in response to the raw food but not the cooked food. However, it is important to remember that these mild symptoms are also frequent in patients who have a more typical allergy to the foods and might be at risk of severe reactions.

Testing for specific allergen components might help identify individuals whose reactions are due to PFAS.

PAL guidance for patients who are low risk for experiencing severe allergic reactions

If you assess your patient as being at low risk for severe reactions, you may suggest that they do not need to be as cautious with certain foods bearing precautionary allergen labelling (PAL). However, it is important to remember that some food products carry a very significant risk of high levels of allergen cross-contamination.

PAL guidance for patients who are high risk for experiencing severe allergic reactions

If you assess your patient as being at high risk for severe reactions, they should be advised to avoid all products bearing PAL, and prescribed adrenaline auto-injectors and should be shown how to use them. They should be advised to carry these and any other emergency medication with them at all times without exception. If for some reason they do not have access to their adrenaline auto-injectors, they should be advised to take extra care to avoid foods with PAL and avoid eating at catering outlets. 

Other tips for keeping food allergic individuals safe

Food allergic patients or parents of food allergic children should:

  • Read ingredient lists and packaging thoroughly, even if they have bought the product before: food companies might change their recipes or introduce new allergens (and, therefore, new risks) to a product that was previously safe
  • Buy from companies they know use PAL responsibly (they can check websites and, if necessary, phone the company concerned)
  • When buying food sold loose either in a supermarket/ market or catering outlet, ensure they tell staff about their allergy and ask to see any written allergen information available; the same applies when eating at catered events (e.g. wedding parties)
  • Encourage food allergic children to ask for their food in restaurants and other food venues, using an agreed form of words, so that it becomes automatic
  • Dvelop a personalised management plan for food allergy that includes a day-to-day strategy and an approach for managing a reaction including knowledge of possible symptoms, and when and how to use an auto-injector.

Products that are high risk for allergen cross-contamination

Because of the way they are made (e.g. on a shared production line), products such as confectionery (e.g. chocolate), cereals and desserts often carry a higher risk of cross-contamination from nuts and peanuts. Dark chocolate is particularly risky: most plain chocolate has a very high risk of milk contamination and should be avoided by milk-allergic individuals irrespective of whether PAL is present or not.

The only exception is if the product has undergone a thorough risk assessment by the food company concerned (which might include testing for residual allergenic proteins) and has been assessed as having no or negligible risk of allergen cross contamination.

It is very important to discuss risk with your food-allergic patient and advise on avoidance strategies, based on a thorough assessment. If you are a GP and your patient has multiple or complex allergies, it is vital that you refer them to a specialist allergy clinic and a specialist allergy dietitian.

Threshold levels

For several years, food scientists and clinicians around the world have been working towards an understanding of threshold doses for food allergens, i.e. the lowest concentration that can trigger an allergic reaction in a significant proportion of allergic consumers. Once a threshold dose has been established and validated for each allergenic food, the food industry can make efforts to reduce cross-contamination to below these levels. This should result in fewer, more consistently applied PAL, which should reduce uncertainty and make food allergen avoidance easier.

Currently, the absence of internationally agreed threshold levels has resulted in inconsistent application of PAL by the food industry.

    Frequently asked questions about PAL

    • Is there a genuine risk of contamination to a particular product or dish and will the allergen always be present in every product purchased?

    No. Some allergens, such as nuts or seeds, are what is termed 'particulate', which means a piece of nut or seed might be present in one piece of (for example) chocolate but not another. Ingredients, such as milk and milk powder, are usually homogeneous, which means they are dispersed throughout the product, so each piece of plain chocolate, for example, is likely to contain milk albeit the same amount. Also, a batch of non-nutty chocolate that has been made immediately after nutty chocolate on the same machinery has a greater risk of cross-contamination than a batch made at the end of the same run. However, a batch of plain chocolate produced immediately after a run of milk chocolate is likely to contain high levels of milk. Food allergic individuals, therefore, should not assume that a product with a PAL will always be safe.

    • Are products that say “may contain traces” or similar phrases less of a risk than those that say just “may contain”?

    PAL is not a legal requirement and there are no legal definitions for phrases. Thus, the wording does not necessarily signify any particular level of risk. So, a product with “may contain traces” or “produced on a shared production line” might carry just as much – or indeed more – of a risk than one stating “may contain”.

    Key messages:

    • Poorly controlled asthma is an important risk factor for severe reactions
    • Patients at high risk of severe allergic reactions should always avoid food with PAL
    • Food allergic patients should not assume a product with a PAL will always be safe
    • Absence of PAL does not necessarily mean there is no risk of allergen cross-contamination
    • Food allergic patients who have been prescribed AAIs should always carry them without exception
    • Carrying an AAI should not be used as a reason for taking risks

    A personalised management plan should be developed, appropriate to age and other factors.

    This summary should be used in conjunction with “may contain” guides for consumers with allergies.

    This short guide has been developed by iFAAM (Integrated approaches to food allergen and allergy management) consortium, a European Union FP7 funded project that aims to improve the management of food allergies. Further information can be obtained from HERE


    Can we identify patients at risk of life-threatening allergic reactions to food? Turner P.J. et al, Allergy 2016

    A food allergy syndrome by any other name? Turner, P.J. et al. 2016; Clinical & Experimental Allergy, 2016 , 44, 1458–1460

    Precautionary allergen labelling: perspectives from key stakeholder groups. DunnGalvin A, et al Allergy. 2015 Sep;70(9):1039-51.

    Charlotte B. Madsen , C.B. et al. Food allergy: Stakeholder perspectives on acceptable risk Regulatory Toxicology and Pharmacology 57 (2010) 256-265

    Food Standards Agency –

    Anaphylaxis Campaign –

    Resources for HCPs:

    Anaphylaxis Campaign

    Anaphylaxis Campaign resources for HCPs & patients

    Anaphylaxis Campaign - Online training

    NICE Quality Standard – Food Allergy

    NICE Quality Standard – Anaphylaxis

    NICE - Anaphylaxis: assessment and referral after emergency treatment

    RCPCH – Care pathway for food allergy

    RCPCH – Care pathway for anaphylaxis