<<Disclaimer: Verify this information before applying it to your situation.>>

Here is the original question:
    ELISA testing for the presence of gluten in a food sample:
    What exactly is being tested, and how sensitive are these tests for the presence of barley and rye?

    And here are the two responses I received:

    ---  THe ELISA test is for gliadin only (wheat) at 200 or 20 ppm (depends on
    test). There is no test for the proteins in barley, rye or oats for home use
    (or even for general industry use)

    AND,

    ---  If you download this PDF document (around 367k) 
    http://coeliac.racetime.com.au/p264_gluten_claims_far.pdf
    around page 14 you will find a section entitled 5: Relevant Issues which
    describes how the ELISA test is able to detect Gluten in either Wheat, rye
    or barley.  Also, Section 4 Background - helps explain the various types of
    gluten.

    This document, published in march 2004 in australia, says that ELISA tests recognize "mainly wheat gliadins and rye secalins, and to a much lesser extent, barley hordeins (including those in malt and malt ingredients), whereas they failed to detect oat avenins." 

    [my note: perhaps this is why budwesier claims there is no gluten present in their rice beer - because the test they are using can't detect barley malt]

    I also received a letter from the makers of Corn Thins. I recently asked them about cross-contamination issues when I discovered that they are now making rye thins in the same facility. They claim to have no contamination. Here is their letter:

    Dear Janice 

    Thankyou for your query on 17th January regarding Gluten testing of our products. You asked what kind of testing we do, and whether the testing can detect Gluten in rye and barley in addition to wheat.   

    We use an external laboratory in Australia to do our Gluten (gliadin) testing. This laboratory is the preferred / recommended gliadin testing provider by the Australian Coeliac Society. We do random testing of all our raw materials (eg whole grain Rice, Corn, Soy, Linseed, Buckwheat, Millet etc.) and finished product (non-gliadin containing) to ensure no gliadin contamination is present.

    The test used is a sandwich ELISA test for gliadin (RIDASCREEN® FAST Gliadin) with a test sensitivity of 5 ppm (mg / Kg). The Website http://www.r-biopharm.com has more info on the Test Kit and Manufacturer. This test system is able to detect the type of gliadin found in wheat, barley and rye. 

    I trust this information answers your query.

    Best regards

    David Bradfield
    Technical Manager
    Real Foods Pty Ltd
    47 Campbell Road
    St Peters
    NSW 2044
    Australia
    Phone:    61 2 85956630
    Fax:        61 2 85956601
    Mobile:    0414919845
    Web: www.cornthins.com

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