IMMUNODETECTION OF ZEARALENONE IN FOOD

Zearalenone is one of the most important secondary metabolites produced by fungi of the different species of the genus Fusarium. Chemically, the structure of zearalenone shows structural similarity to natural oestrogens and therefore induces obvious negative effects in humans and animals. Furthermore, zearalenone is one of the most prevalent mycotoxins worldwide and is frequently found in maize, wheat, barley and other cereals, and occasionally in milk. Currently, two main methods are used for their detection and analysis and determination in samples. The first method is based on HPLC-MS/MS, but requires expensive equipment and highly qualified personnel, resulting in a high cost per sample. On the other hand, for analysis and detection in a large number of samples or for in situ analysis, rapid immunochemical methods are used. Zearalenone, due to its very small size, is not immunogenic, so obtaining the antibodies necessary for the development of an immunoanalytical method for zearalenone requires chemical modification to incorporate the appropriate functionalisation for covalent attachment (conjugation) to carrier proteins. In this way, immunogenic conjugates are obtained which can be used for the immunisation of animals and the production of antibodies (polyclonal and/or monoclonal) capable of binding to azearalenone. The chemical strategies used until now for the conjugation of zearalenone to proteins involve relevant changes in the stereoelectronic properties and/or conformation of the original molecule, most likely resulting in the generation of antibodies with moderate affinity and specificity towards zearalenone. Therefore, the development of immunoanalytical methods with improved sensitivity and selectivity towards zearalenone requires developing new antibodies with improved properties compared to those previously produced. Researchers from Universitat de València and Consejo Superior de Investigaciones Científicas have developed zearalenone analogues (haptens), and immunogenic conjugates thereof, in which the structure and all functional groups of the molecule remain integrated, and therefore available for recognition by the immune system during the immune response and, consequently, by the antibodies generated from it. These derivatives are capable of inducing a highly effective immune response leading to the generation of antibodies of high affinity and specificity towards this mycotoxin, which, together with the corresponding labelled derivatives used as test antigens, enables the development of immunodetection procedures for zearalenone with superior analytical capabilities.