The US Food and Drug Administration (FDA) has previously established that less than 20 parts per million (ppm) of gluten content is a safe threshold for contamination; thus, products with less than 20 ppm can be labeled as gluten-free and are safe for consumption by individuals with celiac disease. In this study, 9% of the tested items had greater than 20 ppm of gluten. This indicates that, though they are marketed as gluten-free, these products are not indeed gluten-free and therefore not safe for consumption by individuals who have celiac disease. Products that were more likely to be contaminated included naturally gluten-free products such as oats, buckwheat, and lentil-based items
On a positive note, the study also found that 86.5% of tested products had lower than 10 ppm of gluten, indicating that they were well below the safe threshold. Higher-cost, certified gluten-free products were least likely to be contaminated. No products that were labeled with the Italian gluten-free certification (depicted) were found to have greater than 20 ppm of gluten.
The findings from this study shed light on the importance of vigilance in regard to cross contamination. For grains that are naturally gluten-free, contamination can occur in the field, during transport and storage, and during milling and packaging. It is therefore recommended that the naturally gluten free grains, such as lentils, are carefully inspected and washed before cooking, particularly when the package is not certified with a gluten free label. Findings from this study also suggest that all parties may benefit from an active policy for training and educating employees in the food service industry regarding the requirements for the GFD.