Tricia Thompson, MS, RD is a nutrition consultant, author and speaker specializing in celiac disease and the gluten-free diet. She is the author of The Gluten-Free Nutrition Guide and has a MS degree in nutrition from Tufts University in Boston, Massachusetts and a BA degree in English Literature from Middlebury College in Vermont.

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Living Gluten-Free

by Tricia Thompson, MS, RD, The Gluten-Free Dietitian

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In light of recent stories about gluten-free foods in the Chicago Tribune, you may be questioning whether the gluten-free food you purchase truly is gluten free.

We do not yet have a definition of “gluten-free” for labeling purposes in the United States, although the Food and Drug Administration should be releasing a final rule within the next several months. To read the proposed rule, please click here.

So until the FDA rule on gluten-free labeling is finalized, what should you ask manufacturers of gluten-free food to ensure that the products you buy contain less than 20 parts per million of gluten?

The first thing that many consumers want to know is whether gluten-free food is produced in a dedicated facility. If it isn’t, ask whether the manufacturer has dedicated production times, uses dedicated equipment, or has scrupulous cleaning standards. Also ask if they have a Hazard Analysis Critical Control Point (HACCP) or Allergen Control Program (ACP) in place.

It is important to keep in mind that just because a gluten-free food was made in a dedicated facility, doesn’t mean all ingredients used to make that product were produced in a dedicated facility. A gluten-free food can only be as “clean” as the ingredients used to make it. This is why it is important that manufacturers have a Certificate of Analysis (that includes gluten) from ingredient vendors and test the ingredients they use in their products for gluten, especially those that are most at-risk for contamination, such as grains, flours, and starches. Ask manufacturers if they test their “raw” ingredients and how frequently.

While gluten testing is important, it must be understood that all tests are not equal " some are better than others.

Two sandwich ELISA tests are frequently used in the United States " the R5 ELISA and the omega-gliadin ELISA. Under current Codex standards the R5 ELISA has been endorsed for gluten analysis. In the Food and Drug Administration’s proposed rule for labeling of foods as gluten-free, the R5 ELISA is being considered for gluten determination.

Neither of these assays is perfect but the R5 ELISA is widely considered to be state-of-the-art. Among other drawbacks, the omega-gliadin ELISA does not accurately assess for barley contamination.

It is important to ask manufacturers what assay they are using to assess gluten and what level of gluten they consider gluten free. No food should be labeled gluten free if it contains 20 parts per million or more gluten. In my opinion, it is very important that manufacturers use the R5 ELISA (the regular and not the fast test) and not the omega-gliadin ELISA to test their final product.

Bia Diagnostics LLC in Burlington, Vermont does a great deal of third party certification gluten testing for many companies in North America. They use the R5 ELISA CODEX approved method (R7001 by R-Biopharm). Each sample tested takes about 3.5 hrs to run due to elaborate extraction protocols and test implementation, but provides the most precise results as compared to other available methods.

According to CEO Thomas Grace, “while quick easy methods (e.g., lateral-flow device, dipsticks, quick or fast ELISAs) can be used for surface screening and/or verification of Certificate of Analysis from vendors ALL methods should be validated before they are employed in a Hazard Analysis Critical Control Points (HACCP) or Allergen Control Programs (ACP).

"Validation usually would consist of taking an ingredient, ingredient mix, and/or finished product negative control and running the test on the sample. If the test is negative, you would then take the samples or sample mixes and add a 20 part per million gluten spike (a proportional mix of wheat gliadin, barley, and rye) into each sample (the gluten spike should be less than 10% of ingredient) and run the test again to be sure you get a positive result for each of the spiked samples.

"If all samples are positive at the level expected, take pure wheat flour (if using “dip-stick method”) and test it to be sure you don’t get false negative results with an over abundance of contaminant. Also, finished products should be periodically checked (every batch if produced on shared equipment or every few months if not) via third party labs using CODEX/AOACRI approved methods.”

You also may want to ask manufacturers if they have been certified gluten free by the Gluten-Free Certification Organization or if their products carry the Celiac Sprue Association Seal of Recognition. These two organizations are providing an invaluable service to consumers by educating manufacturers, especially new manufacturers, on how to make sure their food is gluten free.

To summarize, six of the questions to consider asking manufacturers are (1) what type of facility do you use, (2) is there an ACP or an Allergen HACCP program in place, (3) do you test your “raw” ingredients for gluten, (4) have you validated the testing procedure, (5) do you periodically send your finished product to a third-party lab for testing using the R5 ELISA, and (6) do your products carry either the GFCO or CSA symbol.

NOTE: Prior to his passing, I co-authored a paper with Dr. Enrique Mendez on the various assays to assess gluten content (Commercial assays to assess gluten content of gluten-free foods: why they are not created equal. J Am Diet Assoc. 2008 Oct;108(10):1682-7). If you would like more information about this article, please contact me through my website.


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@ 5:37pm ET on December 9, 2008
Great article Tricia! Nice to see the explanation of validation as well. Have read your article you wrote with Mendez and it is excellent. I believe it is extremely important that people with celiac disease have confidence in the processes used by manufacturers of GF products. Good for you for bringing this topic to your blog!

Beth Armour, RD, MEd.

@ 11:16pm ET on December 9, 2008
Another great article. Thanks Tricia.

@ 7:47am ET on February 23, 2013
Good articles. I would like to state that these are only a guideline that we should follow in our diet plan. Mainly gluten is found in wheat, rye and barley so we should avoid these grains instead of them you can use gluten free snacks or bars for good taste.

I agree that we should follow the gluten free rules in every day meals as it can cause severe health problems as well.

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