Detection of pistachio allergen coding sequences in food products: A comparison of two real time PCR approaches

•A comparison of two real time PCR assays to detect pistachio in foods is performed.•Probe-based qPCR is more effective to detect Pis v 1 target than Sybr®Green.•The method is specific, reliable, and sensitive. LOD: 10 ppm of pistachio.•It was possible to detect pistachio in boiled and autoclaved samples.

The labelled of pistachio on food products is mandatory and, as a consequence, the development of suitable analytical methodologies to detect this nut in processed foods is advisable. In this work, two different qPCR assays to detect pistachio, SYBR®Green and locked nucleic acid (LNA) probes, are tested and compared. Pis v allergen coding sequences have been amplified and cloned in different pistachio varieties, and specific primers and probes for each allergen have been designed. According to our results, LNA probe-real time PCR appears to be the most sensitive and specific method, reaching 10 mg/kg of pistachio. The effect of temperature and/or pressure on pistachio DNA detection was also analysed by LNA probe-based qPCR. Data showed a reduced amplificability of pistachio after thermal treatment under pressure, nevertheless, this effect was not observed after boiling. The applicability of this method has been studied by analysing 14 food products and by comparison with a commercial ELISA kit.