Characterizing the Distribution of Ppm Gluten in Gluten Free Oatmeal Servings Contaminated with a Barley Kernel

Oats are regularly contaminated with gluten-containing grains like wheat, barley and rye. For producers of gluten free oatmeal, contamination potential makes it prudent to understand the consequences in terms of gluten dosing, as labeling requirements specify a gluten maximum. To do this, statistical simulation has been used to produce virtual oat servings (40g) contaminated with either two row or six row spring barley. The results are probability distributions for ‘actual’ ppm gluten (free of measurement influences) and ‘as measured’ via R5 ELISA. Findings show ‘actual’ ppm gluten to be normally distributed with 57 ppm and 41 ppm gluten averages with 14 and 12 ppm standard deviations (stdevs) for two and six row barley, respectively. ‘As measured’ ppm gluten results are lognormally distributed with 61 and 44 ppm gluten averages with 63 and 47 stdevs for two and six row barley, respectively, employing an 80% analytical recovery rate and a multiplier of 1. These analyses show that ‘as measured’ results possess false negative probabilities (relative to a < 20 ppm gluten regulatory requirement) from 0.14 to 0.34 depending on recovery rate and barley type. This work highlights the need for non-homogenous grinding issues to be addressed in whole grain gluten assessment, for analytical recovery rates to be defined for gliadin in oats, and for appropriate conversion factors to be determined in order to attain capable measurement of gluten in oats due to barley kernel contamination.