Development of a TaqMan real-time PCR assay with an internal amplification control for detecting trace amounts of allergenic mango (Mangifera indica) in commercial food products

Mango (Mangifera indica) is a widely enjoyed tropical fruit that is rich in numerous nutrients, but it is also a common allergenic fruit that can induce anaphylactic shock in some mango-sensitized individuals. To protect allergic consumers, a TaqMan real-time PCR is developed herein by targeting the major mango allergen GAPDH gene to identify mango in foods. To prevent interference by other ingredients in the foods, an internal amplification control (IAC) is established and incorporated into the developed qPCR. Under the optimized assay conditions, the developed assay can detect mango genomic DNA down to 10 pg/μL and effectively differentiate mango from 21 other fruits and vegetables. In the incurred assay, the developed qPCR has a limit of detection (LOD) of 10 μg/g and 330 μg/g of mango powder in juice and cookie, respectively. The assay exhibits a board spectrum, successfully detecting six mango cultivars, and has good accuracy and precision as calculated intra- and inter-assay CV values < 10%. Forty commercial processed foods were simultaneously analyzed using the developed method and a qPCR method that is officially recognized by the Taiwan FDA. The sensitivity and specificity of this assay were estimated to be 85% and 100%, respectively, based on the ingredient labeling of these products. Hence, this developed qPCR is an effective method for screening mango in processed foods.