While the Codex list contains the major allergens on a world-wide basis, the foods, which are common causes of allergic reactions, differ between geographical areas, as a result of dietary preferences, for instance. Some countries have chosen to include additional foods on their national list of foods and ingredients that must be declared on food labels. The EU for example has chosen to add celery, mustard, sesame seeds, lupin, and molluscs and products thereof to the list of allergens, which must be declared on food labels.