Chapter 7 - ELISA Tools for Food PDO Authentication

Abstract

Abstract In compliance with the European law (EC No. 510/2006), geographical indications and designations of origin for agricultural products and foodstuffs must be protected against mislabelling. Protected foods exhibit special characteristics derived from the specific area in which the product is produced (geographical) or from their traditional composition or production methods. Typical foodstuffs with recognized protected designation of origin (PDO) are wines, cheeses, oils, honey, beers and meats. However, this list will be expanded in the near future because it is of interest for producers to register their products in the European agricultural product quality policy as PDO. Authenticity and traceability are key issues for the protection of PDO/PGI products. Therefore, EU and member states have developed specific regulations to this end. Recent alerts regarding frauds related to the origin, authenticity, safety and labelling of some PDO/PGI products have weakened consumers’ confidence and caused severe economic damage to producers. In order to protect both the consumer and the honest producer from the mislabelling fraud, it is desirable to develop objective and robust methods capable of discriminating and usable to verify the authenticity of the marketed products. Consumers are very interested in ‘PDO’ products, since they associate these products with quality and healthy foods. Thus, it is necessary to implement analytical methodologies that can assure consumers about the products they purchase. Several analytical tools are used for food control and authentication, mainly chromatographic and electrophoretic techniques. In recent years, genetic and immunological methods are widely being used due to their high specificity and sensitivity. Immunology-based approaches are cost-effective, sensitive, specific and fast, in addition to having other advantages. The immunoassay concept includes simple precipitation of antibody–antigen complexes, agglutination of cells or particles, homogeneous and heterogeneous assays (luminescent, enzymatic, etc.) and finally, immunochromatographic and immunosensing methods. In the new immunoanalytical developments for food authentication, consideration should be given to the selection of the antigen bound by the antibody, the accuracy and matrix effects. Recent research includes detecting the presence of meat from different species in food products, the detection of soy proteins in processed meat products, the presence of vegetable proteins in milk powder, the differentiation of milk from different species, as well as the adulteration of sheep and goat milk with cow milk, or of bovine milk in cheeses made of goat or sheep milk. Furthermore, the validation process, as well as the development and assessment of new reference materials, continues to be an important issue in the authenticity of food products. The goal of this chapter is to offer an overview of the protein-based methodologies with potential to be applied for the authentication of PDO and PGI products, focussing on ELISA configurations. The recent immunological test for detecting proteins and the development of new immunoassay formats, their advantages and drawbacks, are presented. Finally, the need for commercially available validated kits-as well as the future trends and innovative approaches-immunosensors and chips-microarrays and other novel bioanalytical tools- are also discussed.