Page 61 - FoodFocusThailand No.180 March 2021

STRONG QC & QA

Food Allergen

Analysis

Food allergen analysis is the testing of a material or
a surface to identify and/or quantify the presence of a
food allergen. Analytical test results are a useful tool
allergen of interest. LFDs are a qualitative test (indicating present/
absent), rapid, portable and relatively easy to use, however there are for allergen management in food processing and may
some technical limitations (e.g. where a high allergen load may be
present) so always check from kit to kit. LFDs are not equivalent to be used to enhance an allergen management plan
laboratory-based ELISA testing. and can be a valuable tool for a risk–based approach
ATP test kits and protein swabs indicate general hygiene, as they
are not specific to allergen residue, nor representative of allergen to allergen management. Test results can provide
load. All swabbing may be impacted by sanitisers or residues and assurance and verification of critical controls within a
swabbing in general is qualitative and can only be used in easily
accessed areas, so results may not accurately reflect the risk comprehensive allergen management plan and assist
associated with hang up or closed systems. the implementation of quantitative risk assessment.
2. Laboratory Analysis
• Enzyme-Linked Immunosorbent Assay (ELISA) Laboratory Analysis has a critical place in allergen management
Kits: ELISA (Enzyme Linked Immunosorbent Assay) test kits are the but is not a substitute for a robust allergen management
current analytical method of choice for food allergen detection and
the most commonly used for routine food analysis. These test kits plan and requires a clear understanding of the limitations
are available for detecting many of the common food allergen proteins. of analysis.
There is an increasing range of assays available as kit manufactures
respond to industry needs.
ELISA test kits generally focus on specific ‘marker’ proteins. They
should be specific (minimal false positives), quantitative (provide an
allergen concentration) and sensitive (able to detect very low (ppm)
levels of the protein. Although cost and time effective, and relatively
easy to use, result interpretation requires a degree of technical
expertise. There is no single ELISA kit available that will detect all
the relevant allergens under the Food Code in a single assay.
• Liquid Chromatography Mass Spectrometry (LC-MS): Mass
Spectrometry (MS) in the context of allergen detection is a process
that identifies peptide markers from the allergic protein. The analysis
can selectively identify very closely related proteins that may not able
to be distinguished by other techniques. Allergen proteins that have
been altered or broken down by food processing and which may not
be detectable by antibody-based techniques may still be detectable
by MS and the technique has the ability to directly analyze multiple
allergens in a single analysis. This technique may provide a valuable
reference method in the future.
• Polymerase Chain Reaction (PCR): Polymerase Chain
Reaction (PCR) methods detect DNA sequences (of the allergenic
species) not allergenic protein. PCR methods are used to amplify
and detect the DNA of an allergen and can be used to detect more
than two allergens at once. They are specific, sensitive, and qualitative,
can verify or clarify an ELISA result and can detect potentially
allergenic products for which no ELISA test is currently available.
PCR is a complex, laboratory-based method that requires a skilled
analyst and can be useful for food products containing hydrolysed
proteins. However, like all detection methods there are limitations
associated with the impact of food processing. Some processing
methods can destroy detectable DNA, causing false negative results
and food matrices may interfere in the assays. In addition, DNA
methods are not suitable for the detection of certain allergens, where
there are low levels of DNA e.g. egg and milk.
Choosing a Method of Analysis When choosing a method
of allergen analysis, it is critical that there is a clear understanding of
the analytical outcomes and the appropriate application of laboratory
results for each allergen detection scenario. There are many factors

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