Gluten-Free Quaker Oats & Testing with the Nima Sensor, R5 ELISA, & G12 ELISA

Gluten-Free Quaker Oats & Testing with the Nima Sensor, R5 ELISA, & G12 ELISA

November 6, 2017

Please read this entire document very carefully. The information is presented in bullet point format to hopefully make complicated information a bit easier to understand.

Background:

  • A consumer tested a carton of Quaker Oats labeled gluten-free with the Nima Sensor consumer-testing device. Two samples—one cooked and one raw were tested. Both results were “gluten found”.
  • The consumer sent all remaining product in the original container to Gluten Free Watchdog.
  • Gluten Free Watchdog sent the product to an independent lab for testing.
  • The lab tested the oats with the scientifically validated/CODEX Type 1 Method* sandwich R5 ELISA following the oat protocol recommended by the assay manufacturer, R-Biopharm.
    • The oat protocol for testing is to homogenize (grind) 200 grams of oats and test 1.0-gram extractions with the cocktail extraction solution.
    • All four extractions tested below the limit of quantification of 5 parts per million of gluten.
  • A portion of the remaining ground sample was sent to a second laboratory.
    • The sample was tested with the sandwich R5 ELISA and cocktail extraction following the oat protocol.
    • The result was below the limit of quantification of 5 parts per million of gluten.

Question: Why is the result using Nima “gluten found” while the result using the R5 is < 5 ppm?

  • Nima states on their website that if the level of gluten in a sample is below 2 parts per million it will report a “gluten found” result 8% of the time.
    • All four samples tested by the first lab tested below this level.
  • Might the antibody used in the Nima Sensor cross-react with the specific variety of oats in the carton of Quaker oats?
    • To help answer this question, the second laboratory tested the retained sample with the G12 antibody.
      • The G12 antibody and the antibodies used in the Nima device are raised against the 33-mer peptide. This means that these antibodies will detect certain portions of this chain of 33 amino acids.
      • The G12 antibody has known cross-reactivity with some oat varieties.
        • The Nima team states that it is highly unlikely that the antibodies used in the device will show any cross-reactivity with oats.
      • Ten 0.25 gram extractions were tested with the G12 antibody.
      • As was somewhat anticipated, the oats demonstrated low-level cross-reactivity with the G12 antibody.

What does this mean?

  • Unfortunately, it is hard to say.
  • Both labs agree that the sample of oats tested does not contain quantifiable gluten.
  • The limit of detection for the Nima device when testing the oat sample could have been < 2 ppm of gluten.
  • The antibody used in the Nima device may have low-level cross-reactivity to the variety of oats in the product.

Next steps

  • It would be very helpful to test a portion of the retained sample with the antibody used in the Nima device.

*Codex Type 1 Method Definition: “A method which determines a value that can only be arrived at in terms of the method per se and serves by definition as the only method for establishing the accepted value of the item measured.”

 

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