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

Markus Lacorn,Susanne Siebeneicher,Thomas Weiss,Tina Dubois

doi:10.13189/fst.2016.040404

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 s-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.

Highlights

Food allergy is one of the most important public health concerns with only a small number of eight major foods accounting for 90 % of all reactions in sensitized consumers: milk, egg, fish, crustacean shellfish, tree nuts, peanut, wheat, and soybean [1]
Results for the estimation of limit of detection (LoD) in bread bakery mixture, chocolate and sausage are presented in table 2 and revealed values of 0.32, 0.15 and 0.23 mg/kg soy protein
Results for the confirmation of a limit of quantification (LoQ) of 2.5 mg/kg soy protein in bread bakery mixture and margarine are presented in table 3

Summary

Introduction

Food allergy is one of the most important public health concerns with only a small number of eight major foods accounting for 90 % of all reactions in sensitized consumers: milk, egg, fish, crustacean shellfish, tree nuts, peanut, wheat, and soybean [1]. These important allergens have to be labeled nearly worldwide. There is a high probability that patients reacting against other legumes, like beans and peanut, develop cross-reactivity against soy [1]. The potential for accidental intake of soy beans as ingredient or contaminant is increasing for sensitized consumers [3]

Objectives

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Conclusion