Soy is a member of the legume family, which also includes peas, lentils, beans, and peanuts. Allergy to soy is common, affecting roughly 0.4% of infants and children. In the United States, soybeans are widely used in processed food products, incorporated into many meat products, vegetarian foods, dairy foods, soups, and sauces. ELISA SYSTEMS® offers test kits in two formats; ELISA (microwell) for quantitative and Lateral Flow for qualitative analysis of Mustard residues.