The unintended presence of gluten-containing grains (GCGs) in cereals, beans, pulses, legumes and seeds presents a major risk for manufacturers and consumers of gluten-free foods. Gluten-free grains, seeds, pulses, beans and legumes can share many steps of the supply chain with GCGs, including being grown in the same fields, harvested with the same equipment, transported on the same vehicles, stored in the same facilities and processed in the same mills.
Oats are a cereal grain with a very high risk of contamination from GCGs, particularly wheat, rye and barley. In the United States and Canada, this heightened risk occurs because oats, barley, hard red spring wheat and durum wheat have overlapping growing regions; are all seeded between April and June; and are all harvested between July and October.
It is now generally accepted that pure oats uncontaminated with GCGs can be safe for persons who have celiac disease, and many oat suppliers now make gluten-free labeling claims based on their ability to control GCG cross-contamination. These claims are typically supported by results from antibody-based testing as proof that the product meets the definition of gluten-free. However, obtaining representative test samples for antibody-based testing is challenging when analyzing whole grains. Because of their large particle size, increased sample volumes and sample numbers are required to obtain representative data, and the mass differences between different grain types can mean that GCGs may be predominantly found toward the top or bottom of a grain container. Even if a representative sample is obtained and milled into flour for measurement, any gluten within the sample may not be uniformly distributed.
An alternative to antibody-based testing for gluten detection is available for whole grains, seeds, beans, pulses and legumes because contaminating GCGs are visible and identifiable to the trained eye or properly calibrated optical sorting equipment. The use of visual examination resolves many of the problems encountered with antibody-based testing methods, including the sampling limitations and the uneven distribution of gluten in ground flours.
To provide industry guidance in determining the safety of whole grains, beans, seeds, pulses and legumes for the gluten-free market, the Gluten Intolerance Group (GIG) conducted and published a study that describes a sampling plan for visually determining the number of gluten-containing grains per kilogram of whole grain products and the appropriate threshold for meeting GIG’s Gluten-Free Certification Organization (GFCO) requirement of 10 ppm or less gluten.
The GIG study determined that a threshold of .25 gluten-containing grains per kilogram of whole grains sold as specially processed gluten-free product met GIG’s 10 ppm standard. This new threshold takes into account the unique risk whole grain products present to gluten-free consumers, wherein a gluten containing grain in a product like oatmeal will be eaten in one serving rather than being spread out over the entire product package or lot. Although not designed or valid for comparing the performance of processing methods, the study also found that two major processors of gluten-free oats were able to meet the new threshold using different processing methods.
Prior to GIG’s study, the industry interpreted GIG’s 10 ppm standard in different ways when applied to whole commodities. The new gluten threshold and sampling plan outlined in GIG’s study provides valuable guidance to processors and enhances the safety of whole grain products certified by GFCO for consumers.
The study, titled “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,” has been published in a special section of the Journal of AOAC International focusing on food allergens and gluten.
Laura Allred is the regulatory and standards manager for the nonprofit Gluten Intolerance Group (GIG). Allred’s experience includes a background in immunology and eight years of directing a food testing laboratory and test kit manufacturing operation. GIG’s food safety certification programs, the Gluten-Free Certification Organization (GFCO) and Gluten-Free Food Services (GFFS), have been recognized leaders in the gluten-free community for more than 20 years. The GFCO certification logo is the symbol of trust for the gluten-free community, with more than 45,000 products certified worldwide. For more information, visit www.gluten.org.
