Allergy testing

‘May contain nuts’ isn’t good enough: we need a new approach to food allergy testing

Food allergies are on the rise and, despite advances in food safety and good management practices, there are many holes when it comes to allergy testing and allergen-free verification. This article outlines the problems and some solutions.

Anybody suffering from a food allergy will know what a huge cause of anxiety it can be. From forensically examining information on food packaging to having to repeatedly ask restaurant staff detailed questions about their ingredients, it can take up a lot of time and energy. And, even then, there are still uncertainties to deal with.

Labels such as “may contain traces of” or “made in the same factory as” don’t actually quantify the risk to individuals. Less obvious risks than just the ingredients used directly in making a product – such as contamination during transport or storage – also pose a threat.

In our recent study we therefore call for a whole new approach to allergen measurement that we hope could protect allergy sufferers by boosting the accuracy of allergen testing.

Food allergy is a rapidly growing problem in the developed world, affecting up to 10% of children and 2-3% of adults. Exactly why the problem is getting worse is subject to a lot of debate, but it follows a similar rise observed in allergies in general.

Common trigger foods include milk, eggs, shellfish, nuts, fish and even some citrus fruits. Reactions can range from a mild runny nose or sneezing attack to severe skin reactions, throat swelling, vomiting and diarrhoea. On rare occasions these reactions can result in anaphylaxis and prove fatal.

The impact on quality of life for people living with food allergies can be significant and usually requires lifelong avoidance of certain foods. There are also burdens on healthcare, the food industry and regulators.

As well as the threat of contamination, fraud is also a major problem. Fraudsters will put cheaper, illicit substitutes in their ingredients and fail to declare these on the packaging. In these cases, detecting and documenting the presence of allergens proves difficult.

Much of the tests are carried out using enzyme-linked immunosorbent assays (ELISA), which uses antibodies and colour changes to identify allergens in products. However, other ingredients in the food that may themselves be safe can interfere with the results of the test, provoking false positive results.

Keeping equipment clean and keeping finished products segregated from contaminants are also crucial to avoid contaminants. But this often isn’t followed carefully enough and is the reason why producers often resort to the “may contain” labelling.

This is far from ideal – every allergen that gets through the system undetected poses a significant risk to consumer health and the reputation of the food industry.

The need for a gold standard

The key to unlock this problem may be by identifying the lowest concentrations of an allergen that will produce an allergic response in a defined, small proportion of the allergic population.

A substantial amount of work is being done to determine safe thresholds for allergens, but without a standard way of measuring allergens accurately and reliably this work may well be in vain. This also needs support from better regulation to prevent foods being contaminated during transport and storage.

These represent major gaps in the system, and it is only by closing them that we can secure a food chain that is reliable, resistant to fraud and ultimately safe for consumers.

My colleagues and I have called on the EU’s food safety body, DG Santé, to lead the way in addressing the deficiencies in the current system. We outline a grand vision to address the challenges in allergen measurement and analysis and call for action in three main areas.

One is to use computer models to predict what allergens are present in foods and what quantities of these allergens will adversely affect the health of an allergy sufferer. This would make labelling much easier to follow, with information such as “suitable for a sufferer” of a particular food allergy or “not suitable” rather than the current “may contain”.

Another is to develop reference methods which will provide a gold standard for the detection and measurement of allergens in food. Similarly, we also need to create reference materials which can support threshold decisions – samples of foods with known, controlled amounts of allergens present, to allow for checks on the accuracy of allergen testing methods.

Significant international effort and an interdisciplinary approach will be required to achieve these aims and protect allergy suffers. But the reality is, if we fail to manage the risks associated with food allergens through a lack of ability to measure them properly, we will have failed a significant societal challenge.

The Conversation, authored by Chris Elliott, Professor of Molecular Biosciences, Queen’s University Belfast