Development and validation of a quantitative PCR assay for rapid identification of authentic Wolfiporia cocos (F.A. Wolf) Ryvarden & Gilb and adulterant species in food and traditional Chinese medicine

Wolfiporiacocos (F.A. Wolf) Ryvarden & Gilb, formerly was known as Poria cocos ( Wolfiporia cocos, Chinese name "Fu-ling"), has been documented in herbs and healthy food for several decades. Accurate differentiation of its ingredients was crucial for the safety. A set of specific primers were designed to identify authentic Wolfiporia cocos from the three counterfeit species, and the Wolfiporia cocos segment was prepared as an internal positive control. A fluorescent quantitative PCR assay with SYBR green I dye was developed to discriminate authentics from the counterfeits, Fu-ling healthy foods including powders, cakes or biscuits. Furthermore, the assays’ specificity and sensitivity was evaluated with the mimic counterfeiting cakes and commercially available products. Specificity analysis revealed that the primers were specific for Wolfiporia cocos and did not react with other common counterfeits or foods DNA. The results of validation tests indicated that the fluorescent PCR assay could efficiently detect DNA not herbal raw materials but also processed healthy foods as low as 6.32 × 10 4 copies/µL. We have successfully developed the fluorescent PCR assay to discriminate authentic Wolfiporia cocos from the counterfeits, Fu-ling healthy foods. The findings implied that 0.1 mg fraudulent cakes could be detected by the assay at least. The method can accurately identify genuine and counterfeit products with strong specificity and high accuracy.