Duplex real-time PCR using TaqMan® for the detection of sunflower (Helianthus annuus) and poppy (Papaver rhoeas) in commercial food products

Abstract

The paper presents a duplex real-time PCR assay for the simultaneous detection of traces of potentially allergenic sunflower and poppy seeds in commercial food products. For the design of sunflower and poppy-specific primers and two TaqMan fluorescent probes labeled with FAM and HEX respectively, the ITS1 region was selected. The duplex real-time PCR assay did not show any cross-reactivity for all other heterologous plant and animal species tested commonly used in the food industry. Analysis of serially diluted raw and heat-treated sunflower in poppy with a range of concentrations of 0.1–100,000 mg kg−1 and raw and heat-treated poppy in sunflower with the same concentrations resulted in good linearity, with a LOD of 0.1 mg kg−1 of sunflower and poppy content. The duplex real-time PCR assay was applied to verify correct labeling of 238 commercial foodstuffs comprising: nut bars, cookies, chocolates, creams, bonbons, cereals, bread, ice cream, meat products and prepared food products. Results indicate that this duplex PCR is highly sensitive and selective, which makes it suitable for the detection of sunflower and poppy traces in food samples. In addition, it can be useful for monitoring the effectiveness of cleaning processes in the production units of the food industry.