Detection of lupine (Lupinus spp.) DNA in processed foods using real-time PCR

Materials from lupine (Lupinus spp.) plants are used as food ingredients. Even small amounts can evoke allergic reactions in sensitized individuals. The applicability of a recently developed real-time PCR method to the sensitive and specific detection of lupine DNA in processed foods was examined. Using the preparation of pizza as a model, changes in the amplification efficiency and in the limit of detection arising from various processing steps such as freezing and baking were observed. For the starting flour the same limit of detection (0.1 mg/kg) as in raw foods was determined. Freezing of the dough resulted in increased cycle threshold values compared to the flour and the prepared dough. In the baked pizza the detection limit was 1 mg/kg, thus demonstrating the suitability of the method for the detection of lupine DNA in processed foods.