Detection for rice-derived ingredients present in dairy products with real-time PCR method

Objective: This study aimed to establish a real-time PCR method for detection of rice-derived ingredients present in dairy products. Method: Primers and Taqman probe of this assay were designed for specific amplification of rice DNA targeting its root-specific gene gos9 gene.Specificity and sensitivity test was performed to evaluate its utility.The assay was further validated with mixtures of milk powder containing various rice powder and commercial dairy products samples with and without rice ingredients from retail market.Results: The assay was proved to be highly specific for rice with no cross- reaction to bovine, ovine and close- related cereal and plant food ingredients may occur in dairy products.The detection limit was 0.1ng for pure rice DNA and 0.1% ( W/W) for rice flour spiked in whole milk powder, respectively. When applied to detect 21 commercial samples, it yields positive amplification signals for the samples with rice ingredients while negative for those without ones demonstrating corresponded results identical to the species indicated in the food label. Conclusions: The assay provided a fast and reliable mean of potential advantages in routine determination of dairy products for the presence of rice-derived ingredients.