Currently, the risk of allergy is managed mainly through labelling products to warn consumers of potential allergens. However, despite segregation and cleaning procedures, allergens can also enter products through cross-contamination during harvest, transport, storage or processing. This means ‘may contain’-style labels are often used, which are far from ideal. Food fraud also presents acute risks for people with food allergies, for example when expensive nuts such as almonds are replaced with cheaper peanuts.1
But there is a greater problem facing chemists today: we can’t currently detect and measure allergens in food properly. In 2015, when it appeared almond had been detected in cumin and paprika products, the common analytical technique, ELISA (enzyme-linked immunosorbent assay), was found to cross-react with many species from the Prunus genus, which contains almond. It took a team of chemists, molecular biologists and protein mass spectrometrists from the Government Chemist programme at LGC to sort out the problem – incidentally confirming that a previously little known Prunus mahaleb was actually the contaminant in the cumin. Along the way, researchers were disappointed to find the paucity of key bioinformatics data.
Thresholds of elicitation
The key to allergen risk assessment and management may be the concept of ‘thresholds of elicitation’ – the lowest concentrations that produce an allergic response in a defined (low) proportion of the allergic population. A huge amount of work is being done to determine safe thresholds for allergens,2 but without the framework in place to measure allergens accurately and reliably this work will be in vain. Currently, the complexity of food samples, cross-reactivity and the lack of standardised tests present massive challenges for scientists attempting to produce accurate allergen measurements.
Recently, we published a paper in Analyst to outline a ‘grand vision’ that would address the key challenges in allergen measurement and analysis.3 We call on the European Commission’s Health and Food Safety Directorate, DG Santé, to take action in three particular areas.
First, we need bioinformatics studies to provide better or missing DNA and amino acid sequences for major allergen genera so that specific molecular biology and protein mass spectrometry assays can be more quickly developed.
We must also ensure the production of metrologically traceable reference materials – the only way to support global threshold decisions by securing the accuracy of allergen testing
Finally, we need the development of reference methods that will provide a ‘gold standard’ for the detection and measurement of allergens in food.
The recommendations are complex and significant international effort and an interdisciplinary approach will be required to achieve them. The grand vision is designed to secure a food chain which is reliable, resistant to fraud and ultimately safe for consumers.
Will this vision gain traction? It should do. Rarely has such an exciting interdisciplinary scientific endeavour arisen as a solution to a key socially relevant problem. If we fail to realise the promise of future risk management of food allergens through lack of the ability to measure food allergens properly, the analytical community will have failed a significant societal challenge.
Michael Walker is an independent analytical scientist at the Government Chemist programme at LGC, and was a founder board member of the Food Standards Agency, UK.For more information, read this blog post.
1 M Gowland and M Walker, J. Sci. Food Agric., 2015, 95, 1979 (DOI: 10.1002/jsfa.6988)
2 A Muraro et al, Allergy, 2014, 69, 1464 (DOI: 10.1111/all.12398)
3 M Walker et al, Analyst, 2016, 141, 24 (DOI: 10.1039/c5an01457c)
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