Article: Assay Detects Minuscule Amounts Of Gluten In Food

Ever since the FDA ruled on "gluten-free" meaning a food contains less than 20ppm (parts per million), there has been a constant dispute as to whether or not it was the correct limit to set. There were multiple reasons this limit was chosen, including, but not limited to:

• Research has indicated that this is a safe limit for those who suffer with Celiac Disease to consume. 
• Current testing methods only could only detect as low as 5ppm, but 20ppm is a much more available/affordable method. 

One of the things I mentioned above is that the lowest detectable level is 5ppm. That little fact is no longer true. An article was published today stating that a new testing method has been developed that can detect levels as low as .5ppm, which is a whole 4.5ppm less than the previous method.

The article does not state the cost associated with this test or how it compares to methods that can detect up to 20ppm, but at the very least, this is huge progress.

You can find the article in it's entirety here, but if you're not into reading scientific articles, I thought I would summarize a few of the points contained:

• Why was the test developed? "María Jesús Lobo-Castañón of the University of Oviedo, in Spain, and her colleagues work on biosensors and wanted to develop a test for allergens. After learning that a colleague was so gluten-sensitive that even products labeled gluten-free could trigger his symptoms, they decided to devise a sensitive test for gluten."
• Previously, tests relied on antibodies that would "specifically bind to gluten or portions of it." This test uses small nucleic acid receptors (also called aptamers) which are less expensive than antibodies (this could mean this method is similar in cost to the 20ppm test, but this was not addressed). This is also more stable and is easier to make and tweak according to the article.
• Their research found the "aptamer with the greatest affinity for their gliadin fragment." I'm going to risk confusing my readers with scientific jargon now, but I didn't want to summarize the following information and risk misinterpreting it:
• " Aptamer in hand, the scientists put together a competitive gluten detection assay. They attached the gliadin peptide to magnetic beads. Then they mixed a food sample with the beads and added a small amount of aptamer. Any gluten in the food competes with the gliadin on the beads to bind to the aptamer, which allows the researchers to detect very low levels of gluten present in the food. By measuring the percentage of aptamer bound to gliadin, the researchers could calculate how much gluten was in the food, at levels as low as 0.5 ppm."
• They used this test with other flours such as corn and rice to ensure it did not detect gluten in non-gluten containing items, and they were successful. 

Additional research is most certainly needed with this new testing method, but I think it sounds like it holds great promise. Personally, I think it would be great if they could confirm the validity of this test, and make it available for home and commercial use at a reasonable cost. 

There may not be a test that can detect levels as low as 0ppm, but .5ppm is HUGE progress in comparison to 5ppm. 

Photo credit: celiacdisease.about.com