1 inch round mustard allergen labels, featuring an easy to peel sticker that leaves no residue, used to indicate that an item of food contains mustard. Not only has it always been important to people with allergies to be aware of what is contained within food, it has since became part of legislation that, as of December 13th, 2014, all ingredients in a product must be listed, highlighting any of the fourteen allergens contained within the regulatory list. Mustard is a commonly found in curries, soups, salad dressing, meat products and sauces.