Is it possible to test for gluten in our food?
Testing processes revealed...
Today, much of our population is aware of Coeliac Disease and the need to avoid gluten as a result. Most of us, as coeliacs, would know that even a 'little bit' of gluten should not be consumed on the gluten free diet. We, as diligent coeliacs, avoid the four gluten-containing grains: wheat, rye, barley and oat. Some of us tend to avoid products with 'may contain traces of gluten', etc. statements as a precaution to maintaining sound health. We generally don't experiment with this diet due to possible dangers but of course enjoy having a life as well.
Not so much of our population (including those affected by Coeliac Disease), however, are aware about how gluten is detected in the laboratory (or how it isn't detected, should I say).
Gluten is a generic name for the proteins found in wheat (gliadin), rye (secalin), barley (horedin) and oats (avenin). Gluten, the substance itself , can not be tested for (under the Enzyme-linked immunosorbent assay (ELISA) common, currently the most widely used and mainstream for testing allergenic proteins in laboratories) . However, the protein fractions of wheat and rye, namely gliadin and secalin respectively, can be tested down to a 5 parts per million (ppm) detection limit. There is currently no accurate test available for detecting oats and barley (particularly malted barley) products at this point in time.
Edited: It has come to my attention (from recent comments) that it IS now in fact possible to adequately test for gluten content in wheat, rye and barley. It is only these ingredients in malted form that are unable to be labelled as gluten free. Oats, on the other hand, are the only exception to this.
Excerpt from FSANZ (page 15) http://www.foodstandards.gov.au/_srcfiles/ACF2A90.pdf
Gluten Free Labelling Laws
Claims in relation to gluten content of food
(1) Claims in relation to the gluten content of food are prohibited unless expressly permitted by this code.
(2) A claim to the effect that a food is gluten free must not be made in relation to a food unless the food contains –
-- (a) no detectable gluten; and
-- (b) no –
-- -- (i) oats or their products; or
-- -- (ii) cereals containing gluten that have been malted/their products.
Statement (2(a)) refers to the wheat and rye which can be tested for to reveal a 'no detectable gluten' reading. A product labelled 'gluten free' may list 'wheat' or 'rye' products in the ingredient listing as long as it contains NO DETECTABLE GLUTEN and guidelines in (2(b)) have been met.
Statement (2(b(i))) refers to the fact that as oats cannot be accurately tested for avenin, the product must contain NO oat-derived ingredients to be labelled 'gluten free'.
Statement (2(b(ii))) refers to the fact that as cereals containing gluten that have been malted cannot be accurately tested for gluten content. As such, the product must contain NO malted gluten containing cereals (i.e. wheat, rye barley or oats) to be labelled as 'gluten free'.
Australia, out of all countries around the world, has one of the most strict labelling polices in place with regard to gluten free labelling. For an item to be classified as 'gluten free', it must contain NO DETECTABLE GLUTEN on testing as well as no oats/oat products or malted cereals containing gluten.
It appears that many individuals and organisations are not fully aware of these facts. The scary part is, how gluten free is our food? In Australia, due to tight labelling regulations on our food, I can say that we are very lucky to be able to trust foods that are marked 'gluten free'. Other parts of the world, however, should especially take heed to this information as it is important to be aware that testing a product for 'gluten' itself remains impossible. Testing can only be done to ensure that a product doesn't contain any detectable wheat or rye. Whether minor amounts of barley or oats are present in our 'gluten free' foods remains a mystery one cannot answer.