Development of Antibodies and Immunoassays for Monitoring of Nitrofuran Antibiotics in the Food Chain

Nitrofurans are a broad group of drugs once widely used for the treatment of microbial and protozoal infections in many livestock species. However, as concerns grew globally with regard to the potentially carcinogenic and mutagenic effects of their residues in foods, they have been banned from use in many parts of the world. In order to monitor compliance to these bans, it is essential to have fit-for-purpose testing methods. Immunoassays are the screening tool of choice for many testing laboratories due to their relative low cost, ease of use and high sensitivity. As is the case with all immunoassays, the most important reagents required are high quality, high affinity antibodies that exhibit the required sensitivity and specificity. Generating such antibodies for the nitrofuran family of compounds has required a great deal of effort in the design of immunogens, as the compounds, due to size, are not capable of eliciting an immune response in hosts and are not easily conjugated to carrier proteins. This article reviews the range of strategies used to successfully generate suitable antibodies to a wide range of these drugs and their metabolites. In addition, the platform technologies for nitrofuran detection have moved from simple enzyme-linked immunosorbent assay (ELISA)-based procedures to more sophisticated multiplexing systems which can undertake faster and broader spectrum testing for the parent drugs and their metabolites. Reviews of the technologies used for immunochemical detection of the nitrofurans and of commercially available test kits are also presented. Keywords: Nitrofuran antibiotics, AOZ, antibodies, immunoassays, food safety, derivatisation, hapten, immunogen.