LC-MS/MS Allergen Testing: How it works and the key benefits

Food allergen detection is most commonly performed using ELISA (enzyme linked immunosorbent assay), which identifies allergenic proteins present in a sample. The second most common method is PCR (polymerase chain reaction), which detects the allergen specific DNA. Both techniques are well established and readily available in laboratories specializing in food testing.

Less commonly used, but increasingly important, is LC MS/MS (Liquid Chromatography–Tandem Mass Spectrometry). In this article, we focus on LC MS/MS, providing a brief overview of how the method works and how it is applied to the detection of allergenic proteins through their peptide fragments.

What is LC-MS/MS?

LC-MS/MS is an advanced analytical technique used to detect food allergens by identifying specific protein fragments, known as peptides, that are unique to individual allergenic sources.

For each target allergen, multiple unique peptide markers are identified and selected. Detecting several markers for a single allergen enables the method to be highly specific. In addition, LC-MS/MS allows multiple allergens to be analyzed simultaneously within a single test run, offering greater efficiency in terms of both time and cost when compared with methods that require individual tests per allergen.

How does LC-MS/MS work?

The process begins with homogenization of the sample to ensure a representative sub sample can be taken. Proteins are then extracted from the sample using an extraction process tailored to the allergen of interest and the food matrix.

Following extraction, the proteins are treated with an enzyme that breaks them down into smaller fragments known as peptides. The prepared sample is then introduced into the LC-MS/MS system.

During liquid chromatography (LC), peptides are separated based on their chemical properties. They next enter the tandem mass spectrometer (MS/MS), where they are detected according to their mass to charge ratio and fragmentation pattern. The resulting fragmentation pattern is a unique fingerprint for the target allergen.

What are the key benefits of LC-MS/MS for allergen testing?

One of the key advantages of LC‑MS/MS is its high specificity. By targeting multiple peptides that are unique to each allergen, this method significantly reduces the risk of false positive results compared with alternative techniques such as ELISA. Cross‑reactivity is a recognized limitation of ELISA and can lead to false positive detections. A well‑documented example is mustard analysis by ELISA, where the presence of rapeseed has been shown to generate positive results.

LC-MS/MS is also less impacted by food processing conditions such as heating or fermentation, which can denature intact proteins. As the method detects specific peptides rather than intact proteins, it remains effective even when proteins have been degraded during food processing. In addition, the ability to analyze multiple allergens in a single run improves laboratory efficiency.

Our laboratory in Hebden Bridge, UK, LC-MS/MS Allergen Screen is UKAS accredited for swab samples. Ideal for surface and environmental swab samples. Contact our team to discuss your requirements and review pricing.

Click here to discover more about our allergen management services.

For further information, please contact:

Dr. Emma Ridley
General Manager, Hebden Bridge Laboratory
Health & Nutrition - Food
t: +44 (0) 151 350 6666