Real-time PCR Methods for Identification of Animal or Plant Species
Barbara Brežná and Ľubica Piknová
from: Real-Time PCR in Food Science: Current Technology and Applications (Edited by: David Rodríguez-Lázaro). Caister Academic Press, U.K. (2013)
Abstract
Real-time PCR authentication of the biological species in food is justified by creating fair market environment for producers by discouraging fraud. Authenticity also needs to be guaranteed, when local food-manufacturing traditions are protected by regulations, such as Protected Geographical Status (PGS) framework of the European Union. Furthermore, the consumers have a right to correct information about the food content, so that they are able to make informed choices regarding possible food allergies, special diets based on nutritional quality or religious and cultural taboos. Last but not least, endangered biological species need to be monitored along the food chain to fight poaching and illicit trade. The real-time PCR assays for authentication of species are summarized in tables and the considerations regarding the assay design are discussed. The choice of suitable DNA marker is crucial for the specificity of the real-time PCR assay. The assay should be empirically validated on a panel of samples, which are desired to score as positive, for instance cultivars of the species, as well as broad range of those desired to score as negative. Detection of almond and distinction between bread wheat and durum wheat illustrate the problematic situations regarding assay specificity. The sensitivity of the qualitative assay can be enhanced by choice multi-copy gene as a marker, however single-copy genes are considered more suitable for quantitative assays due to copy number stability. Amplification control should be included in real-time PCR assays to add reliability to the results. The optimal approaches to determine the limit of detection and to ensure correct quantification are still debated read more ...
