Abstract
Spelt products are popular with consumers achieving higher market prizes, making them susceptible to food adulteration with less valuable cereals. To facilitate product control, a recently developed duplex droplet digital PCR method enables the detection and quantification of common wheat (Triticum aestivum) contaminations in food products made from spelt (Triticum spelta). The duplex droplet digital PCR assay targets the γ-gliadin gene and the Q-locus of both subspecies. In this study, the method was validated in an interlaboratory ring trial involving 11 participating laboratories. Test materials containing defined proportions of spelt and common wheat were prepared and tested. The ring trial procedure included DNA extraction of the test samples and determination of subspecies proportions using droplet digital PCR. Results from the ring trial confirmed the method's capability for specific detection and quantification of common wheat in spelt, with acceptable relative measurement uncertainties, and without requiring reference material for calibration. To our knowledge, this is the first interlaboratory validation of a digital PCR method for species differentiation in food.
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Acknowledgements
We thank the members and guests of the working group “Molecular biological methods for plant and animal species differentiation” in context of § 64 of the German Food and Feed Code (LFGB) for their participation in the study and their fruitful comments.
Funding
This work was supported by the Federal Office of Consumer Protection and Food Safety (BVL). Laboratories which participated in the interlaboratory ring trial received partly financial support by the BVL.
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The authors declare that there is no conflict of interest in this paper. Each of the authors confirms that this manuscript has not been previously published and is not currently under consideration by any other journal. In addition, all authors have approved the content of this paper and have agreed to the submission policy of the Journal of Consumer protection and Food Safety. Each named author has contributed substantially to the conduct of the underlying research and to the preparation of this manuscript. In addition, to the best of our knowledge, the named authors have no conflicts of interest, financial or otherwise.
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Waiblinger, HU., Bruenen-Nieweler, C., Frost, K. et al. Interlaboratory validation of a droplet digital PCR method for quantifying common wheat (Triticum aestivum) in spelt (Triticum spelta) products. J Consum Prot Food Saf (2024). https://doi.org/10.1007/s00003-024-01503-x
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DOI: https://doi.org/10.1007/s00003-024-01503-x