Project news New robust detection method for allergens in food

04/03/2021

Severe food allergies occur in 5% of adults and 8% of children. It is very important for them that their food products are free of the allergens that make them ill. In order to be able to improve the accuracy of the list of ingredients on the label even more, a new detection method has been developed via VIB/UGent-ILVO doctoral work by Kaatje Van Vlierberghe. The method is very accurate, and simultaneously detects the allergens peanut, hazelnut, milk and egg. But it is especially accurate in foods that have undergone processing steps such as high heating and mixing in a fatty matrix. This is important, because the allergenic strength of nuts, dairy or eggs can actually strengthen, weaken or even disappear with certain processing steps.

The improved detection method ensures that enforcement - through analytical control - is strengthened. "The way is thus open to allergen labeling that better corresponds to what is really present in the final product, and thus more certainty and reassurance for people with food allergies," says promoter Christof Van Poucke.

Chocolate bar with hazelnuts

Accurate and simultaneous detection of food allergens

The method consists of the combination of liquid chromatography and tandem mass spectrometry (LC-MS/MS), and simultaneously detects and quantifies 4 allergenic ingredients (milk, egg, hazelnut and peanut). The substances that reveal whether an allergen is indeed present are allergen-specific peptides generated from food proteins. These peptides (a series of certain amino acids) have been carefully selected based on their robustness against food processing.

Influence of food processing on allergen detection.

Food processing can be seen in a very broad sense, ranging from the heating of ingredients to destroy dangerous microorganisms (for example, during milk pasteurization), to complex processing procedures where a variety of ingredients are mixed and processed into a final product (for example, in the preparation of cookies). These food processing procedures have a major impact on the nutritional components of a raw material but equally on the unique marker molecules (such as DNA fragments and proteins) specific to that raw material that are used to detect their presence in the final product. Therefore, it is best to develop analytical methods that are robust against influences of food processing so that they can be universally and routinely applied, and to generate accurate and reliable results.

Quantification of food allergens

In addition to reliable detection, accurate quantification of food allergens is also important in order to assess the risk to the patient. Certain very low concentrations of food allergens will be tolerated by the majority of the allergen population. Validation of the developed method was therefore also an important part of the PhD. The method is capable of accurately and simultaneously detecting and quantifying (traces of) egg, milk, peanut and hazelnut in both cookies and chocolate. These matrices were chosen because they are representative of many food products and because the preparation process (heating and high fat matrix) is known to have a negative impact on the detectability of the markers. The test materials, which were used in the elaboration of the analytical techniques and their validation, were produced in a standardized way.

Danger of cross-contaminations

European legislation requires that 14 allergens be specifically listed when used as ingredients. Unfortunately, the chance of accidental presence of food allergens in food products is always real due to cross-contaminations, for example through the shared use of food processing machinery. Although these are only traces of the allergenic ingredient, such small amounts can still cause an allergic reaction and thus pose a health risk.

Post-processing detection and simultaneous detection of allergens as major advantages

The developed technique can be used as a confirmation method for faster and cheaper detection methods such as ELISA and PCR, which are often used in official controls, or as an alternative to these methods that only allow the simultaneous detection of one allergen. The developed method can detect four simultaneously. In time, it may be possible to detect several to all allergenic ingredients at once where detection is not affected by processing.

Cooperation between National Reference Laboratory (ILVO and CER) and VIB

These research results came about thanks to a collaboration between the Food Pilot of the Institute for Agricultural, Fisheries and Food Research (ILVO) and Flanders' Food, the Flemish Institute for Biotechnology (VIB), Ghent University, CER groupe and the University of Namur. The research was funded by the FPS Public Health. ILVO and CER together form the NRL for Allergens (National Reference Laboratory) for Belgium. The tasks include the comparison of protocols and thus the evaluation of existing detection kits for food allergens, the follow-up of research in diagnostics, the performance of validation studies, ring tests, preparation of reference material, organization of workshops and training sessions, knowledge dissemination on diagnostics and the detection of food allergens in all kinds of samples. Currently the newly developed method is being looked into for accreditation so that it can be offered as a routine method to both the competent authorities and the food industry.

On October 27, Kaatje Van Vlierberghe defended her PhD: "Food allergen detection: well-defined test materials and accurate peptide biomarkers for development of a mass spectrometry-based detection and quantification method. Supervisors of the PhD are Prof. Kris Gevaert (VIB/UGent) and Dr. Christof Van Poucke (ILVO).
ILVO - VIB - UGent

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Christof Van Poucke

ILVO researcher

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