Validation and comparison of the Copan Milk Test and Delvotest SP-NT for the detection of antimicrobials in milk

The Delvotest SP-NT and Copan Milk Test, two microbiological tests designed for screening antimicrobial substances in milk were compared and validated. The performance criteria described by the European Decision 2002/657/EC were used for the study. Both tests were evaluated with visual and automated reading (scanner) and the validation was performed on 10 different antibiotics (penicillin-G, cloxacillin, sulfamethazine, sulfadiazine, oxytetracycline, gentamicin, cephalexin, cefquinome, dihydrostreptomycin and trimethoprim). Both tests were found to detect penicillin, cloxacillin, sulfamethazine, sulfadiazine, cephalexin and gentamicin at or below the EU maximum residue limits (MRLs). Some other antibiotics such as oxytetracycline, dihydrostreptomycin, trimethoprim and cefquinome were not detected or only with a low sensitivity. Both tests were found easy to use, robust and fulfilled EU requirements.