One simple crumb of this size contains enough gluten to its ingestion can cause a number of important digestive discomfort in people with celiac disease or non-celiac gluten sensitivity, when they are following a diet free of gluten. Consuming gluten even in small quantities, whether voluntary or not, carries potential risks of triggering associated diseases, so it is important warning about it. This is made frequently without knowledge to it and is considered as a part of the so-called "cross contamination".