A NOVEL RAPID ENZYME-IMMUNOASSAY (FLUOROPIAOS BETASCREEN) FOR DETECTION OF BETA-LACTAM RESIDUES IN EX-FARM RAW-MILK

A novel, qualitative enzyme immunoassay based on fluorescence detectio n for determination of beta-lactam antibiotics in raw, commingled milk (Fluorophos BetaScreen E. U. test) was evaluated. A dose-response pro file for penicillin G was constructed by analysis of spiked milk sampl es. The limit of detection, defined as the concentration of penicillin G that resulted in 95% of the samples being evaluated as positive, wa s 1.8 mu g/kg. The repeatability of the assay was very high both withi n and between the three participating milk quality testing laboratorie s. In total 5,061 randomly selected tanker milk samples were analyzed with the BetaScreen test and compared with the Delvotest SP. The agree ment between the two tests was 99.7%. Probably due to a higher sensiti vity to penicillin G, the BetaScreen test detected almost twice as man y suspect positive tanker milk samples (0.45%) as the Delvotest SP (0. 26%).