Development and validation of a sandwich ELISA for the determination of potentially allergenic lupine in food

The paper presents a sandwich enzyme linked immunosorbent assay (ELISA) for the detection of traces of lupine proteins in foods. Anti-lupine antibodies were produced by immunising a rabbit and a hen with a protein extract from white lupine flour. IgY were used as coating and IgG as secondary antibodies. The ELISA detects proteins from white (Lupinus albus) and blue (Lupinus angustifolius) lupine and, with a lower sensitivity, proteins from yellow (Lupinus luteus) lupine. The ELISA does not show any cross-reactivity with 34 plant species potentially used in lupine containing foodstuffs. Accuracy, repeatability, limit of detection (LOD) and limit of quantification (LOQ) were determined by analysing model biscuits and noodles containing from 0 to 10,000 ppm lupine flour. Lupine flour could be detected in the unprocessed doughs as well as in the processed products down to a spiking level of 1 ppm.