6 Common Myths about Food Allergen Testing

Ask anyone with a food allergy and they will tell you the same thing: there’s not much that’s simple about a quick trip to the grocery store. They have to check every label on every product that goes into the basket to make sure that their food is free from allergens. Because there is no treatment for food allergies, there’s only one thing that works: completely avoiding the allergen or allergens in question.

This makes it all the more crucial for food producers to conduct routine tests for potential allergen contamination in their products.

Yet this isn’t as simple as it sounds.

Food products can range widely from straight raw materials, such as cereals, to highly processed ready-to-eat products. Their composition, moreover, varies according to the amount of protein, fat, salt and other compounds present. Test methods are expected to analyze all food sample types for allergens with equally reliable results. This, however, is often far from achievable in reality.

With all the complexity surrounding food allergen testing, perhaps it’s not surprising that there are a lot of half-truths and myths out there. Here, the allergen experts at Romer Labs dispel six of the most common misconceptions about food allergen testing.

Myth #1: A test kit off the shelf works with any food matrix.

The facts:

Take the test kit from the shelf and start testing… Sounds tempting, doesn’t it? The results would be quick, but are they reliable? In reality, food products are highly diverse and certain test methods may work better for certain food samples. The extent of processing adds further complexity to this equation.

With new or unfamiliar matrices, we always undertake a spike recovery validation at three different levels to make sure it works with our kits and covers the detection range of the assay. Some matrices, such as chocolate, are full of tannins and other polyphenols that bind to allergenic proteins, creating insoluble complexes from which it is difficult to extract without adding extra protein to the extraction buffer.

While implementing an allergen control plan, it is highly recommended that the selected allergen test method be fully validated on the food producer’s specific food matrices.

Learn more about test kits and food matrices here.

Myth #2: “May contain…” statements can solve all our problems.

The facts:

Food allergen labeling – though intended to make the lives of people with allergies easier and safer – often causes confusion as most laws fail to state the levels above which an allergen must be labeled. Advisory “May contain…” statements are voluntary and often serve primarily to prevent the producer from having to make potential allergen-related product recalls.

Studies have shown that up to 9% of products with advisory labels in fact contained detectable levels of allergens. This means that there is a real risk of allergen contamination in products that only make a precautionary statement. As there are varying reasons why manufacturers include such statements, consumers find it increasingly difficult to interpret them.

Consumers with allergies should avoid products with precautionary labels, as the risk is not assessable. In return, food producers should avoid using a “may contain…” statement without reasonable suspicion.

Learn more about “May contain…” labels here.

Myth #3: PCR is more reliable than immunological tests.

The facts:

It depends. Polymerase chain reaction (PCR) assays are extremely sensitive and make sense when specificity is called for. For example, no antibodies have been developed that can reliably detect celery without also giving a signal for related species, such as fennel, carrot or parsley. Hence, celery detection with an immunological test is currently not possible.

How can specific species be detected with PCR? It relies on DNA extraction and amplification, which is made possible by the nature of DNA: it is a stable molecule that remains unaffected by most common food processing methods. Yet PCR has significant drawbacks: it requires specially trained personnel to perform the complex sample preparation and result interpretation. Furthermore, the DNA molecule itself is not responsible for the allergic reaction, meaning that the presence of DNA is at best an indicator of the allergenic potential of the sample.

Immunological rapid tests are still the gold standard and should be preferred in most cases as they directly detect food allergens. However, when specificity is called for, PCR may be a great alternative.

Learn more about PCR in allergen testing here.

Myth #4: Mass spectrometry will soon replace allergen rapid tests.

The facts:

Mass spectrometry (MS) is a high-end technology that is already used in several fields for routine analysis and shows some potential in allergen analysis: it can measure several allergens in parallel. However, it is still in its infancy and is currently restricted to research applications. As a result, it’s not clear how MS will perform in routine analysis.

Additionally, MS is not yet able to deliver the highest level of accuracy. Its basic principle is one of fragmentation: a molecule – in this case the allergenic protein – is broken down into small pieces (peptides) and their mass is subsequently determined. However, food processing can affect the fragmentation process of proteins, resulting in varying peptide patterns.

Without a doubt, MS technology will continue to develop and improve in the future. Yet since it relies on highly trained personnel and expensive equipment, there will still be demand for fast and inexpensive in-house testing, making it rather unlikely that rapid tests such as ELISAs will be replaced.

Learn more about MS in allergen testing here.

Myth #5: All test kits on the market detect the same.

The facts:

Commercially available test kits do not perform in the same manner. For each food allergen, there is a variety of different allergenic proteins, but there is no recognized standard defining which of them must be detected. Therefore, we cannot assume that all test kits detect the same and consequently give comparable results.

Kits do have one thing in common: the overall target (e.g. peanut or casein). But the similarities end there. Different kits use different buffers and procedures, which can have an impact on the extraction process and generate diverging patterns. Furthermore, kits differ in the antibodies used, which, in an added layer of complexity, need to take the various methods of food processing into account.

So what should you do? A close discussion with the kit manufacturer is highly recommended as they can provide information about the test kit’s performance specifications. Also, analysts should carefully review and summarize all the processing steps that are applied to a food product to assess which kit is most suitable for their individual application.

Learn more about how test kits differ here.

Myth #6: Currently available “allergen reference materials” improve testing reliability.

The facts:

It may be a controversial assertion, but it’s the truth: there are no allergen reference materials, despite the claims by some producers. In other fields of food safety, producing reference materials requires high-end technology, but the procedures for doing so are well-established. If we take mycotoxins for example, we have one defined molecule, allowing accurate calculations of the final concentration.

In contrast, with food allergens, there is not just one specific molecule; an allergenic commodity consists of a mixture of different proteins. To date, several allergenic proteins have been identified, but many have not yet been well characterized. Furthermore, the protein pattern varies between different cultivars of the same species. And to make matters worse, proteins can change their conformations as a result of processing, which may lead to a change in their allergenic potential.

So what are these so-called “allergen reference materials”? Typically, they are mixtures of allergenic food commodities in certain matrices. Such mixtures do have their uses in checking regular test performance, provided that they are used with care and in consideration of all known limitations. Materials that are produced in-house using the matrix in question result in even more significant evaluations of test performance and represent the best possible alternative we currently have until standardization bodies define specifications for actual reference materials.

Learn more about “allergen reference materials” here.

Looking for a reliable, rapid-test food allergen system?

Watch the video and learn how AgraStrip® can help you keep your production system allergen-free:

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