A collaborative trial to evaluate the performance of a multi-antibiotic enzyme-linked immunosorbent assay for screening five banned antimicrobial growth promoters in animal feedingstuffs

The uses of five antimicrobial growth promoters (AGPs) zinc bacitracin, spiramycin, tylosin, virginiamycin and olaquindox in animal feedingstuffs have been prohibited in the European Union (EU) since 1999. The development and validation (in-house) of an immunoassay-based multi-analyte screening procedure for simultaneously detecting five banned AGPs was achieved as part of an EC funded project (Feedstuffs-RADIUS). The resultant test has been adapted to an enzyme-linked immunosorbent assay (ELISA) kit format and its performance was assessed in a collaborative study. A total of 15 laboratories drawn from DG SANCO's Committee of Experts on Methods of Analysis of Feedingstuffs (CEMA) group representing government agencies and private industry in the EU participated in this collaborative study. Six incurred materials of three different feed types were analysed. The analysis of 231 reported results revealed an overall false non-compliant rate of 1.9% and a false compliant rate of 0% at concentrations of antibiotic in the region of 20% of their previous minimum inclusion rates (MIR). The developed procedure, when used in control laboratories, to monitor for the presence of the banned antibiotics, will have a major impact on the ability to enforce the European ban on these substances.