Accurate and Sensitive Quantification of Soy Proteins in Raw and Processed Food by Sandwich ELISA

Abstract

Soy belongs to the so called "Big 8" allergens and following food labeling directives of many different countries soy has to be labeled as ingredient if used in food. Allergen labeling statements enable sensitized patients to avoid the intake of food containing soy. The major allergenic proteins in soy are Glycinin (Gly m 6) and ß-Conglycinin (Gly m 5). The sandwich ELISA RIDASCREEN ® FAST Soya quantifies these two proteins in unprocessed as well as in processed food. The following performance characteristics were validated: Selectivity, limit of detection, limit of quantification, precision, recovery, and robustness. First results from proficiency test rounds verified these validation results. In summary, the assay shows high precision and very good recoveries for all different types of samples. It is robust against normal occurring variation within a laboratory. Compared to other test-kits on the market, this ELISA is suitable for the recognition of unheated to strongly heated soy proteins in various foods. Therefore the test can be used for most samples on the market that contain intact soy protein.