Analyse des allergènes alimentaires - Entre fiction et réalité (4)

Si l’analyse des allergènes alimentaires semble assez simple au premier abord, il existe néanmoins de nombreuses difficultés associées, qui sont susceptibles de transformer une analyse exacte en une procédure assez complexe.

Au cours des dernières années, les chercheurs se sont intéressés à l’utilisation de la spectrométrie de masse pour détecter les allergènes. La littérature scientifique compte de nombreux rapports prometteurs sur les performances de cette méthode et il est généralement admis qu’elle pourrait révolutionner le domaine de l’analyse des allergènes alimentaires.

Ce quatrième numéro de notre série est consacré à l’idée reçue fausse selon laquelle la spectrométrie de masse remplacerait bientôt les kits rapides d’analyse pour devenir la future méthode de référence en matière d’analyse des allergènes.

Will mass spectrometry soon replace allergen rapid tests?

Mass spectrometry (MS) is a high-end technology that is already used in several fields for routine analysis. Today, researchers all over the world are trying to adapt this method for the detection of food allergens. The goal is clear: MS should not only improve the accuracy of analytical results for single allergens, but it should also be capable of multi-allergen analyses from one single sample.

How Allergen MS measurements work
Any MS analysis follows the same basic principle: a molecule – in our case the allergenic protein – is broken down into small pieces (peptides) and their mass is subsequently determined. This fragmentation process always results in the same protein fragments. The obtained peptide pattern allows the identification of allergens at high levels of accuracy and sensitivity.

Could this be the future allergen reference method?
MS is a very promising method for allergen analysis. However, it is still in its infancy and is currently restricted to research applications. As a result, we don’t know how MS will perform in routine analysis. Multi-methods are feasible and would greatly facilitate the work of service laboratories. However, considering multi-methods as a reference method is not realistic because an accurate definition of marker peptides for each allergen would be required and food processing affects the fragmentation process of proteins, resulting in varying peptide patterns.

MS does not yet deliver the highest level of accuracy
The fragmentation process may not only be affected by food processing. The tryptic digestion also causes varying results because the reproducibility of this approach is very limited. Another bottleneck of MS technology is the extraction efficiency. A method can only detect what has previously been extracted from the sample. Recent studies have shown that recovery rates of ELISA and MS measurements are at least comparable and in some cases better for ELISA kits.

Will MS replace rapid tests?
Without a doubt, MS technology will continue to develop and improve in the future. It might become a valuable tool for multi-allergen analyses in service laboratories, in the same way that it is commonly used for mycotoxins already. However, accurate results from MS requires highly trained personnel and extremely expensive equipment. There will always be a demand for fast and inexpensive in-house testing, making it rather unlikely that rapid tests such as ELISAs will be replaced.

 

This article was originally published in "International Food & Meat Topics", Volume 28 Number 4 (2017)