Modified starch is used in many products and can be derived from a variety of sources. If the source is a cereal that contains gluten, manufacturers must list this in the ingredients list in line with the EU wide allergen labelling law, for example modified wheat starch. If you see modified starch on the ingredients list and it does not refer to a cereal that contains gluten, such as wheat, this must be from a cereal that does not contain gluten and is gluten free.