Study defines threshold for meeting gluten-free standard

A study published in the Journal of AOAC International provides industry guidance in determining the safety of whole grains, beans, seeds, pulses, and legumes for the gluten-free market. The purpose of the study was to determine a Gluten-Free Certification Organization (GFCO) threshold level for the maximum number of gluten-containing grains (GCGs) within a kg 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.

As the researchers explain, 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. GFCO enforces a 10-ppm gluten threshold for both ingredients
and finished products and has an interest in ensuring a safe supply of grains, legumes, beans, pulses, and seeds for use in gluten-free products.

The threshold set by GFCO in the study—0.25 GCG/kg of whole grains sold as specially processed gluten-free product—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.

The researchers analyzed the visual examination data of GCG counts across multiple batches and crop years of oats from Cream Hill Estates and Grain Millers to determine whether these processors would have been able to meet the proposed threshold. The Cream Hill Estates and Grain Millers facilities were chosen for evaluation because they are both dedicated oat facilities but use different methods—Purity Protocol and proprietary sorting equipment, respectively—to achieve gluten-free product.

The researchers concluded that the use of visual examination—either with the trained eye or properly calibrated optical sorting equipment—resolves many of the problems encountered with antibody-based testing methods, including sampling limitations and the uneven distribution of gluten in ground flours. In addition, they found that the two major processors of gluten-free oats were able to meet the new threshold using different processing methods.

Study