Challenges of Maintaining Gluten-Free Levels in Non-Gluten Containing Crops

A recently published study looks at the determination of gluten in gluten-free oats, and other grains, seeds, beans, pulses, and legumes.    For food to be considered gluten free, the level set by US regulation is 20 ppm.   There can be a problem with cross contact into other non-gluten crops especially oats.  Oats are grown in overlapping regions and are seeded and harvested in the similar time frame.  It is interesting to consider the difficulty in ensuring gluten-free status back to the crops and initial processing steps.

"Processors who intentionally produce gluten free grain ingredients for food manufacturers must take additional steps to ensure that their products are appropriate for gluten free consumers. These steps can include controls during growing, harvesting, transport, storage, and processing. Once these additional steps are taken, the processor must be able to demonstrate that the resulting ingredient meets the requirements for gluten free labeling according to the country of sale or other applicable regulations."

Whole grains can be a challenge for testing and setting a ppm limit.  This study evaluated a visual method for determining the feasibility of the limit in oat processing facilities.

Journal of AOAC Interntational
https://www.gluten.org/wp-content/uploads/2017/12/Oat-Study.pdf
The Use of Visual Examination for Determining the Presence of Gluten-Containing Grains in Gluten Free Oats and Other Grains, Seeds, Beans, Pulses, and Legumes

LAURA K. ALLRED, CYNTHIA KUPPER, and CHANNON QUINN
Gluten Intolerance Group of North America, 31214 124th Ave SE, Auburn, WA 98092
ALLRED ET AL.: JOURNAL OF AOAC INTERNATIONAL VOL. 101, NO. 1, 2018 1

Abstract
Obtaining representative test samples for antibody based testing is challenging when analyzing whole
grains for gluten. When whole grains are ground into flour for testing, confocal microscopy studies
have shown that gluten tends to exist as aggregates within the starch background, making single-sample testing inaccurate and complicating the ability to arrive at an accurate average from multiple samples. In addition, whole-grain products present a unique risk to gluten free consumers, in that any contamination is localized to specific servings rather than being distributed across the product lot. This makes parts-per-million values less relevant for whole-grain products. Intact grains, seeds, beans, pulses, and legumes offer an alternative opportunity for gluten detection, in that contaminating gluten-containing grains (GCGs) are visible and identifiable to the trained eye or properly calibrated optical sorting equipment. The purpose of the current study was to determine a Gluten Free  Certification Organization threshold level for the maximum number of GCGs within a kilogram of nongluten grains sold as specially processed gluten free product and to determine the feasibility of this threshold by evaluating visual examination data from two major oat processors.