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AboutTricia 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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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.
2.Do you test your at-risk “raw” ingredients for gluten and how frequently do you test? 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.
3.Have you validated your in-house testing procedure? According to Thomas Grace, CEO of Bia Diagnostics “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.”
4.Do you periodically send your finished product to a third-party lab for testing using the R5 ELISA? 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. It addition, it also is important that manufacturers test their highly hydrolyzed products using the competitive R5 ELISA.
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 www.glutenfreedietitian.com.
Hopefully some of your questions have been answered and concerns addressed. If not, let me know!
Tricia Thompson, MS, RD is an internationally recognized expert in celiac disease and the gluten-free diet. A researcher, consultant, and writer, she is the author of The Gluten-Free Nutrition Guide, The Complete Idiot’s Guide to Gluten-Free Eating, and The American Dietetic Association’s Easy Gluten-Free: Expert Nutrition Advice with More Than 100 Recipes. For more information on celiac disease and the gluten-free diet, visit Tricia’s website at www.glutenfreedietitian.com.
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