Collaborative study of a microbiological screening method (three-plate) for the banned antimicrobial growth promotors tylosin, virginiamycin, spiramycin, zinc bacitracin and avoparcin in animal feed.
A microbiological screening method (three-plate) for the detection of the antimicrobial growth promoters tylosin, spiramycin, virginiamycin, zinc bacitracin, and avoparcin in animal feed has been developed and validated successfully. A collaborative study involving 18 laboratories receiving 172 samples was carried out to verify the performance characteristics. The detection level for tylosin/virginiamycin/spiramycin, expressed in microbiological activity, was 1 mg kg(-1) (false-positives, 2%; false-negatives, 3, 0, and 6%, respectively). Avoparcin could be detected at 1 mg kg(-1) in feed in general (false-positives, 2%; false-negatives, 0%). However, in calf feed the sensitivity was lower. The percentages of false-negatives were found to be 12%, 7%, and 0% at 1, 3, and 5 mg kg(-1), respectively (false-positives, 4%). The limit of detection for zinc bacitracin was 3-5 mg kg(-1) (false-positives, 5-10%; false-negatives, 77% at 1 mg kg(-1), 45% at 2 mg kg(-1), 12% at 3 mg kg(-1), and 4% at 5 mg kg(-1)). The method allowed for a distinction to be made between the groups of antibiotics: avoparcin/zinc bacitracin versus tylosin/virginiamycin/spiramycin. This definitely gives added value to the method in the framework of a follow-up of positive screening results by post-screening and confirmatory analysis.
Pol-Hofstad
I
I
RIKILT Institute of Food Safety, Wageningen, the Netherlands. Irene.Pol@wur.nl
Driessen-Van Lankveld
W
W
Tomassen
M
M
De Jong
J
J
Van Egmond
H
H
D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis*; D001414:Bacitracin / Q000032:analysis; D001681:Biological Assay / Q000379:methods; D004350:Drug Residues / Q000032:analysis*; D005504:Food Analysis / Q000379:methods; D006020:Glycopeptides / Q000032:analysis; D006133:Growth Substances / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015572:Spiramycin / Q000032:analysis; D015645:Tylosin / Q000032:analysis; D014769:Virginiamycin / Q000032:analysis
D000900:Anti-Bacterial Agents; D006020:Glycopeptides; D006133:Growth Substances; D014769:Virginiamycin; D001414:Bacitracin; D015572:Spiramycin; C016249:avoparcin; D015645:Tylosin