Page 47 - FoodFocusThailand No.233 August 2025

STRONG QC & QA

category for labeling in 2024. In 2025, cashew nuts, currently which relies on the specific binding of two antibodies to the
on the recommended allergen list, are being considered for allergenic protein. Therefore, this technique is not suitable
the mandatory list and pistachio is also being considered for foods in which proteins may have been partially digested
to be added to the recommended list. Meanwhile, China or degraded, as the antibodies may no longer recognize
introduced a new national general standard for the labeling them. Additionally, ELISA can produce false positives
of prepackaged foods in March 2025, requiring food labels due to cross-reactivity, where antibodies react with
to declare 8 allergens: cereals containing gluten, crustacean structurally similar proteins—for example, detecting shrimp in
shellfish, eggs, fish, peanuts, soybeans, milk, and tree nuts. a product that only contains mollusks. Conversely, it may yield
This regulation will be fully enforced in 2027. false negatives in products where proteins have been broken
down, such as fermented or hydrolyzed foods. Today, some
Allergen Detection Techniques in the Food Industry companies have developed Competitive ELISA kits that can
For food manufacturing facilities—especially those with multiple detect peptides from allergenic proteins in foods that cannot
production lines, the risk of cross-contamination with protein be tested using Sandwich ELISA. Available test kits include
allergens is often unavoidable. Therefore, allergen residue those for detecting beta-lactoglobulin in milk and gluten.
testing plays a crucial role in quality control. The techniques 2.2 Liquid Chromatography with Tandem Mass
used can generally be divided into two main categories: Spectrometry (LC-MS/MS) -This technique offers high
qualitative testing and quantitative testing. accuracy and specificity and can simultaneously detect
1. Qualitative Testing: This group of techniques focuses multiple unique peptides from allergenic proteins without the
on determining whether an allergen is “present” or “absent” in cross-reactivity issues associated with ELISA. It also requires
a sample, without specifying the exact quantity. It is suitable for only a small sample volume. However, LC-MS/MS is still
screening or monitoring purposes. Examples include: under development and lacks international standardization,
1.1 Protein Residue Testing — This method is based on so its implementation requires thorough validation of its
the principle of using chemicals that change color upon contact ability to identify specific food allergens and the stability of
with proteins. It helps indicate whether protein residues remain target proteins.
on surfaces or equipment. However, it cannot identify whether Overall, selecting an appropriate allergen detection
the protein is allergenic. Therefore, this technique is more technique should consider multiple factors, including the
suitable for verifying the effectiveness of cleaning procedures objective of testing, budget, personnel expertise, and the type
rather than confirming the presence of an allergen. of food being analyzed. Using a combination of techniques
1.2 Lateral Flow Assay (LFA) Test Kits are a technique can improve accuracy and reduce the likelihood of errors. For
for detecting allergenic proteins based on the binding between example, LFA may be used for routine monitoring along the
antibodies and allergenic proteins. This method provides rapid production line, while ELISA or LC-MS/MS can be employed
results within 30 minutes and does not require specialized for official confirmation in laboratory settings.
equipment or personnel. The test kits can be used on food As allergen labeling standards become increasingly
products, equipment, or surfaces to assess allergen control stringent worldwide, food industry operators must prioritize
along the production line. However, the method has certain allergen control systems throughout the entire production
limitations. Its detection sensitivity typically ranges from 0.5 to process. This includes quality control of raw materials,
10 ppm, and it can detect only one type of allergen per test. cleaning procedures, segregation of production areas,
Therefore, for products that may contain multiple allergens, and final product testing. Selecting appropriate analytical
testing should prioritize those allergens with the highest risk. techniques, combined with accurate knowledge and
Today, tools have been developed to interpret LFA results as understanding, will truly build confidence for both producers
semi-quantitative or quantitative data, offering an additional and consumers.
option for monitoring allergens in the production process.
1.3 Polymerase Chain Reaction (PCR) Technique -This
technique detects the genetic material (DNA) of allergenic
ingredients. PCR offers high specificity and can accurately More Information Service Info C006
differentiate between ingredients with similar allergenic
proteins, such as mollusk, shrimp, and squid. It is commonly
used to confirm results from ELISA tests and can detect multiple
allergens in a single sample. Additionally, PCR can identify เอกสารอ้างอิง / References
allergens that ELISA cannot detect, such as celery. However, 1. FAO and WHO. 2022. Risk Assessment of Food Allergens. Part 1
it is not suitable for foods that lack DNA or have undergone – Review and validation of Codex Alimentarius priority allergen list
processing that destroys genetic material—such as milk, through risk assessment. Meeting Report. Food Safety and Quality
eggs, oils, and highly heat-processed foods. The technique Series No. 14. Rome.
also requires specialized equipment and trained personnel 2. FAO & WHO. 2024. Risk assessment of food allergens – Part 4:
to perform. Review and establish exemptions for the food allergens, Meeting
2. Quantitative Testing: This type of testing focuses on report. Food Safety and Quality Series, No. 17. Rome.
accurately measuring the amount of allergens present in food. 3. Food Allergy Research and Resource Program (https://farrp.unl.
edu/)
It is used in quality control and safety certification processes 4. Kawai, Hiroyuki (2025, March 5). Draft Amendments to the Food
to support allergen labeling on food products. Labelling Standards and the Classification of Cashew Nuts and
2.1 Enzyme-Linked Immunosorbent Assay (ELISA) Pistachios as Allergens. Label bank. https://label-bank.com/blog/
ELISA is the most widely used standard technique for allergen foodlabel/202503foodlabel
detection. It detects one allergen at a time with high sensitivity 5. Kawai, Hiroyuki (2025, January 8). Summary of the status of legal
and can be used for both food and surface testing. The most changes on food labelling in Japan. Label bank. https://label-bank.
common form used for allergen detection is Sandwich ELISA, com/blog/foodlabel/202501foodlabel

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