Certifying the feed to guarantee the quality of traditional food : an easy way to trace plant species in complex mixtures.

Food/feed authenticity and related correct product labeling are very important issues, not only as a guarantee for human health safety but also for the protection of traditional products. To ensure authenticity and counteract events of product adulteration, reliable techniques for food/feed control are required. This article presents a simple and rapid PCR-based method (TBP), that can be used as a powerful tool for identifying nearly any plant species in blends of plant origin. The method relies on the presence of intron-specific DNA polymorphisms in the plant ²-tubulin gene family. By performing a simple PCR reaction, using degenerated universal primers designed on the ²-tubulin exon regions flanking the intron sequences, a characteristic amplification pattern is obtained for each analyzed plant species, allowing its unambiguous identification in mixtures of plant origin. As a practical case, the method has been successfully applied on commercial feeds, fed to cows whose milk is used for the production of the Italian Bitto PDO cheese. The fact that the analysis can be performed regardless of any information about the plant genome under investigation, its ease of use, rapidity of execution, reliability and reproducibility, all make the proposed method a diagnostic technique with a wide range of applications in the context of feed/food quality certification.