Development and validation of a duplex real-time PCR method for the simultaneous detection of celery and white mustard in food

The developed duplex real-time PCR method allows the simultaneous detection of traces of potentially allergenic white mustard (Sinapis alba) and celery roots (Apium graveolens var. rapaceum), celery stalks (A. g. var. dulce) and leaf celery (A. g. var. secalinum). The duplex assay does not show any cross-reactivity with 64 different biological species, including various members of the Brassicaceae and Apiaceae family. In raw model sausages spiked with white mustard and celery roots, the LOD was found to be 0.001% white mustard and 0.005% celery. In model sausages brewed at 75–78 °C for 15 min the LOD was found to be 0.005% white mustard and 0.005% celery. The duplex real-time PCR assay was applied to check if commercial food products are labelled in compliance with the legal regulations.