What does the term ‘thresholds’ refer to?
The threshold dose for a food allergen is the lowest amount that can trigger an allergic reaction if eaten.
For some years scientists around the world have been working to establish the threshold doses for several major allergenic foods. Once a threshold dose has been established for each of them, the food industry can work to reduce cross-contamination to below those levels.
Precautionary allergen labelling is currently adopted by food companies to warn people that a product may have been in contact with an allergen during the food production process.
The aim of introducing allergen thresholds is to limit the use of precautionary allergen labelling (also known as PAL or ‘may contain’ warnings) so that it is only used where a food poses a real risk; while at the same time ensuring that people with food allergies are well-protected.
Scientists are confident they have enough information on threshold doses for eleven allergenic foods (or groups of foods) to enable regulators such as the Food Standards Agency (FSA) and Food Standards Scotland (FSS) in the UK to offer strong guidance to food manufacturers on the actions they need to adopt to protect people with food allergies.
Those allergenic foods are peanut, milk, egg, some tree nuts (hazelnut, cashew), soy, wheat, mustard, lupin, sesame, shrimp/prawn. Information about fish and celery is still being analysed.
Views have been offered by several different organisations including regulators, industry representatives, doctors and patient groups.
This information sheet aims to help people with food allergies to understand the whole issue of thresholds.
What is the problem with precautionary allergen labelling?
In our view, precautionary allergen labelling is over-used and therefore lacks credibility. It has been seen on the labels of products that we believe must be very low risk; for example, ‘nut traces’ warnings have even been seen on the labels of bottled water.
Because precautionary allergen labelling lacks credibility, it is often ignored. In the case of some products, where the risk is real, this could be dangerous.
Where has an allergen threshold already been established?
A threshold dose has been established for gluten, part of certain cereals such as wheat that are involved in coeliac disease, a common digestive condition
Under UK law, products labelled ‘gluten-free’ must contain no more than 20 parts per million of gluten (equivalent to between one and two tablespoonfuls in a tonne of food). The description ‘gluten-free’ is based on the principle that this level will be safe for people with coeliac disease
People with wheat allergy should be aware that the term ‘gluten-free’ may not be relevant to them because they may react to a product with less than 20 parts per million of gluten if a reasonable portion is eaten, or they may react to other wheat proteins. They may like to read our fact sheet on wheat allergy.
The case for establishing thresholds
In our view, there are various reasons to support this argument:
• Food industry action based on agreed thresholds will lead to a reduction in the use of ‘may contain’ labels and make those that remain more meaningful.
• There will be greater consistency in allergen labelling throughout the food industry and as a result there will be less confusion among customers. In our view this will lead to greater safety for people with allergies.
• Not introducing generally agreed thresholds may lead to even more precautionary labelling, further limiting the choices available to people with food allergies.
• Studies have offered reassuring evidence that reactions to small amounts of an allergenic food (of the order of thresholds proposed for the food industry) will be mild in the vast majority of cases.
• The fact that an allergic person’s own threshold can vary from day to day has been taken into account by scientists working on thresholds.
In our experience, the most severe allergic reactions are normally caused, not by extremely small amounts of allergen, but by significant quantities of allergen, added intentionally as an ingredient to the food. In such cases, there is usually a major error made somewhere along the way, either by the person supplying the food or the person eating it.
The case against thresholds
Not everyone agrees with the idea that allergen thresholds should be used to limit the use of precautionary labelling.
Calls to our helpline suggest that the main argument against is based on the perception that extremely small amounts of a food allergen can kill. Although, in our view, this perception may be largely founded on scare stories and extreme cases, small amounts of an allergen can trigger symptoms in people who are highly allergic. Any symptom, however minor, can provoke anxiety, with the worry that it could progress to something more serious.
Furthermore, an allergic person’s own threshold can vary from day to day. How much they react to at any given time may depend on factors such as their general state of health, how well their asthma is controlled, whether they have been exercising hard or drinking alcohol, and other factors. Even if industry works to agreed thresholds, would these limits be misleading if a person can react to lower amounts at certain times?
It is understandable that people should question whether any industry actions based on agreed thresholds will protect 100% of the allergic population all of the time, although this does not differ in principle and practice from protection against other hazards in food.
The answer is that there is likely to be a very small minority of people who are so susceptible to an allergen that they could react to an amount below any thresholds that might be set. However, the scientists doing the work believe that any such reaction – should it occur – is likely to be mild and not require treatment.
What has the scientific work involved?
The international scientific group leading the way has drawn on the experiences of Australia’s VITAL labelling system (Voluntary Incidental Trace Allergen Labelling). A lot of the scientific work is based on food challenges – where allergenic foods are fed to patients in a controlled hospital setting to test how much allergen they react to. Proposed values for thresholds now rely on several thousand individual challenges, to which more are added on a regular basis.
In June 2016, an international debate among interested parties held in Belgium reached conclusions on the key issues connected with thresholds and precautionary allergen labelling. Delegates included representatives from the food industry, food safety authorities, the scientific community and patient organisations.
Key conclusions included:
• The use of precautionary allergen labelling should be subject to defined conditions, which food producers would need to adhere to if they wished to use it. This means that in the food production chain there would be documented risk assessment and appropriate allergen management procedures to address cross-contamination.
• Communication is crucial. The wording of precautionary allergen labelling must be clear and consistent. And consumers need to know that a product has undergone a risk assessment if it does not have a precautionary allergen statement.
• Guidance for the food industry on good risk assessment practice is required.
Where are we now?
The thresholds currently proposed need to be reviewed by the FSA and FSS before they can be adopted into official UK guidance. This will need to be in line with the law on the provision of food information to consumers. Many organisations are working together to ensure that the matter gets high priority.
What does the future hold?
If the established thresholds become part of official UK guidance to the food industry, we believe there will need to be a transition period allowing food companies time to change their labels. During that transition period we would advise people to be proactive and contact manufacturers and retailers if they have questions about individual products.
Once food companies begin responding to any new official guidance by changing their labelling, it will be vital, in our view, that the full implications of what the guidance means are communicated to people with food allergies. People will want answers to questions such as: If there is no ‘may contain’ label on a product, does this reliably mean I can eat it? There will be difficulties in understanding relating to allergenic foods for which there are no established threshold levels. Such communication comes under the remit of the FSA and FSS. The Anaphylaxis Campaign will also play its part in keeping people with allergies informed.
A positive development is that ‘may contain’ wording is likely to be standardised, instead of there being many ways of expressing the possibility of cross-contamination.
An important question is: What system will be in place to notify the public of those products whose threshold based labelling have still caused a reaction? This would be a matter for the FSA and FSS to deal with. The FSA has a system whereby people can register to receive alerts. These also appear in the Agency’s website.
All cases of food allergy should be medically reviewed. Initially you should see your GP, who may find it necessary to refer you to a hospital allergy clinic. The degree of risk on your own case, and the need for any individual avoidance measures, can then be discussed.
The text of this article has been peer reviewed by Dr Alexandra Croom, Consultant Allergist, Spire Hospital Nottingham; and Dr René Crevel, Director of René Crevel Consulting Ltd.
Publication: February 2018
Review: February 2021
Dr Crevel has been a leading scientist working with global experts in developing allergen thresholds that will be safe for people with food allergies. Dr Croom has nothing to disclose in relation to this fact sheet.
All the information we produce is evidence based or follows expert opinion and is checked by our Clinical and research reviewers. If you wish to know the sources we used in producing any of our information products, please let us know, and we will gladly supply details.
The information provided in this factsheet is given in good faith. Every effort is taken to ensure accuracy. All patients are different, and specific cases need specific advice. There is no substitute for good medical advice provided by a medical professional.