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Is PCR relevant for gluten testing?
Well, ELISA RIDASCREEN® Gliadin is the reference method as it detects directly the gluten proteins. Why should you be using PCR?
- Only PCR allows cereal differentiation in gluten testing. The most used method is the protein based ELISA. However, with DNA analysis various cereals can be discriminated. Using our real-time PCR test SureFood® ALLERGEN 4plex Cereals wheat, barley and rye are independently detected.
- PCR detects oats besides wheat, rye and barley. While the ELISA RIDASCREEN® Gliadin does not detect oat, the PCR kit SureFood® ALLERGEN Gluten detects oat and other gluten containing cereals. The test kit can also be used for reciprocal confirmation of ELISA results.
- Individual and specific detection of oat. SureFood® ALLERGEN Oat determines the presence or absence of oat, which is important for food labels.
Table 1 Overview of qPCR kits and their application fields
| Test kit | Application |
|---|---|
| SureFood® ALLERGEN 4plex Cereals (Art. No. S7006). Separate identification of wheat, barley and rye. | Track down gluten contamination source in gluten free foods in order to avoid future cross- contaminations. |
| SureFood® ALLERGEN Gluten (Art. No. S3606). If the DNA of gluten containing cereals e.g. oat, wheat, rye or barley is present, the test gives positive results. | Confirmation of positive ELISA results. Oat can be classified as gluten containing or gluten free depending on national legislation. The PCR kit is able to detect also oat, which might be important for labeling. |
| SureFood® ALLERGEN Oat (Art. No. S7004). If the DNA of oat is present, the test gives a positive result. | The kit determines the presence or absence of oat, which is important for food labels. Production / Lab of oat-free food products after processing oat-milk on same the production line. |
R-Biopharm – your expert when it comes to gluten analysis
R-Biopharm is the world market leader in gluten testing; we provide the widest range of test systems for the detection of gluten. Food manufacturers, laboratories and other service providers use our broad product portfolio of reliable and precise test kits for gluten analysis worldwide.
What is gluten and why is the analysis of gluten in food a particular focus?
Gluten is a protein mixture found in cereals such as wheat, rye and barley. Oat is a controversial issue: Under the Australia New Zealand Food Standards Code, oats and products containing them are not permitted to be labelled gluten-free.
There are people who suffer from a permanent gluten intolerance, known as coeliac disease, which leads to inflammation of the small intestine. The only treatment option for coeliac disease is a strict gluten-free diet.
According to the Codex Alimentarius (CODEX STAN 118-1979) foods are “Gluten-free” if they contain < 20 mg/kg gluten. The limit value of 20 mg/kg gluten has been transposed into many national legislations.
The CODEX recommends further that the ‘R5 Méndez ELISA’ method should be used for the detection of gliadin/gluten in gluten-free foods. ‘R5 Méndez ELISA’ method is a Codex Alimentarius Type I method. The type I categorization gives it the status of a reference method. R-Biopharm is the only R5 ELISA manufacturer that offers the Cocktail (patented) (Art. No. R7006 / R7016) and thus fulfills the requirements of the reference method 100 %.
Method overview – which method is right for you?
R-Biopharm offers lateral flow rapid tests, ELISA and PCR tests as can be seen in the table below. So when should you be using which method?
- Our lateral flow tests for surfaces and food. Do you want to know quickly, if your surfaces of your production equipment or your plant have been sufficiently cleaned? Then use our unique R5-based RIDA®QUICK Gliadin lateral flow tests, which can be carried out without laboratory equipment. Directly swab surfaces with the strip – cleaning control has never been easier. Furthermore, quickly check whether your food contain gluten or not.
- The most versatile gluten ELISA range for food testing. Depending on your needs, R-Biopharm offers a variety of different gluten ELISA test systems, includingthe ELISA RIDASCREEN® Gliadin as the most used and best validated method for gluten detection..
- PCR for confirmation and species identification. PCR is a very sensitive and specific method, which allows qualitative and quantitative measurements.
Table 2 Gluten detection method options
| LFD | ELISA | PCR | |
|---|---|---|---|
| Analyte | Protein | Protein | DNA |
| Test result | Qualitative | Quantitative | Qualitative and quantitative |
| Field of application | Cleaning – and process control, analysis of food samples | Analysis of raw materials and final products | Analysis of raw materials and final products. Confirmation analysis |
| Advantages | Fast results, cheap, no or little equipment needed, no skilled staff needed | Established and validated method | Cereal species identification. Standardized sample and test procedure. |
Why offers R-Biopharm so many different gluten test kits?
The ELISA RIDASCREEN® Gliadin is the reference method for gluten testing. However, some customer need faster or more sensitive results:
- RIDASCREEN® FAST Gliadin for faster analysis
- RIDASCREEN®FAST Gliadin sensitive for a lower limit of detection
The choice of test kit depends also strongly on the food matrix and its processing. During baking, fermentation and hydrolysis, proteins are often modified. This has an impact on protein detection methods like LFD and ELISA referring sample preparation and whether a sandwich or a competitive ELISA format should be used:
- RIDASCREEN® Gliadin competitive for fermented or hydrolyzed products such as beer, syrup or sourdough
- RIDASCREEN® Total Gluten for the quantitative determination of intact (non-hydrolyzed) gluten from gluten-containing cereals (wheat, rye and barley) in oats and oat products
DNA as an analyte is very stable. Therefore, the DNA sample preparation can be applied to nearly all foods and is standardized across our PCR test kits:
- SureFood® PREP Advanced for DNA preparation of all kinds of food including highly processed food
- Quantification is possible with SureFood® ALLERGEN Gluten using the reference material SureFood® QUANTARD Allergen 40
The table below highlights the different test kits and food matrices.
| Analyte | Test kit | Food matrix |
|---|---|---|
| Protein | RIDA®QUICK Gliadin (Art. No. R7003/4/5) | R5 LFD in sandwich format for rapid, qualitative determination of CIP water, surfaces and food samples (raw and processed) |
| RIDASCREEN® Gliadin (Art. No. R7001) | R5 Sandwich ELISA for the quantitative determination of intact (non-hydrolyzed) gluten from gluten containing cereals (wheat, rye and barley) in food | |
| RIDASCREEN®FAST Gliadin (Art. No. R7002) | Similar to R7001 except shorter incubation time | |
| RIDASCREEN®FAST Gliadin sensitive (Art. No. R7051) | Similar to R7001, because of a lower calibrator more sensitive | |
| RIDASCREEN® Total Gluten (Art. No. R7041) | Sandwich ELISA for the quantitative determination of intact (non-hydrolyzed) gluten from gluten containing cereals (wheat, rye and barley) in oat and oat products | |
| RIDASCREEN® Gliadin competitive (Art. No. R7021) | R5 competitive ELISA for quantitative determination of fermented and hydrolyzed food (e.g. beer, starch) | |
| DNA | SureFood® ALLERGEN Gluten (Art. No. S3606) | qPCR for qualitative and/or quantitative detection (use SureFood® QUANTARD Allergen 40) of gluten containing cereals – e.g. wheat, rye, barley, oats in food |
| SureFood® ALLERGEN Oat (Art. No. S7004) | qPCR for qualitative detection of oat in food | |
| SureFood® ALLERGEN 4plex Cereals (Art. No. S7006) | qPCR for qualitative detection and differentiation of wheat, barley, rye in food |
Do you have further questions?
Contact us at info@r-biopharm.de
