Detecting soybean and milk in dairy and soy products with post-PCR high resolution melting assays

Abstract

We have developed and validated post-PCR (polymerase chain reaction) high resolution melting (HRM) based assays that allow identifying the presence of two major allergenic foods – soybean and bovine milk – in food products. A new set of primers for PCR was developed for detection of the gene encoding the soybean protein lectin. The assay was validated using reference samples and used for the analysis of artificially prepared mixed samples of dairy and soy products of different matrices, as well as of real products available in the market (spray creams). The limits of detection (LODs) of the soybean (8 copies) and bovine milk (4 copies) assays were lower compared to LODs of other previously published PCR-based assays. The analysis of several commercial spray creams revealed an undeclared presence of soybean in one of the samples. The newly developed HRM assays are precise and robust alternatives for the control of food composition and falsification by competent authorities.