Gluten cross contact in oats: retrospective database analysis 2011 to 2023

It is long-established that oats are at substantial risk for cross contact with gluten-containing grain. Specially processed gluten-free oats, whether purity protocol or mechanically/optically sorted, made it possible for this grain to be included in a gluten-free diet in the U.S. Gluten Free Watchdog (GFWD) (Manchester, Massachusetts, United States) has been assessing the gluten content of labeled gluten-free foods since 2011. In 2022, there was an apparent increase in the number of oat products testing with quantifiable gluten at or above 5 mg/kg or parts per million (ppm). The purpose of the present study was to assess the levels of gluten in foods containing oats to determine if there were any trends. In this retrospective database analysis, GFWD product test reports from April 2011 to May 1, 2023 were searched using the term "oat." The search identified 213 individual packages of food that contained the word "oat" in the ingredients list. The test results for these packages of food were reviewed. Of these, 24 (11%) tested with quantifiable gluten greater than or equal to 5 mg/kg (ppm). The percentage of oats testing with quantifiable gluten varied per year but spiked in 2022 at 35%. It is not possible to know for certain what caused this increase. The drought during the oat growing season of 2021 could be a major factor. This drought impacted oat crops in both the US and Canada and led to one of the worst oat crops going back over 150 years. One limitation of this study is that it was a retrospective analysis. Different numbers of oat products were tested each year and these were often different brands of oats and different oat formulations. To assess the level of gluten cross contact in oats going forward a much larger prospective study should be conducted.