Higgins H C, McEvoy J D G
Chemical Surveillance Department, Department of Agriculture for Northern Ireland, Veterinary Sciences Division, Stoney Road, Belfast BT4 3SD, UK.
Food Addit Contam. 2002 Sep;19(9):819-28. doi: 10.1080/02652030210145063.
Three plate systems (combinations of indicator organism and growth medium) were evaluated for the detection of analytical standards of the banned feed additives avoparcin, bacitracin zinc, spiramycin, tylosin and virginiamycin. When authorized in the EU, the previously recommended minimum inclusion rate (MIR) for each compound was 5 mg kg(-1). One of the plate systems (Micrococcus luteus ATCC 10240, nutrient agar) detected all five additives. This plate was used in a further study that evaluated the suitability of accelerated solvent extraction (ASE) as a first step in the development of a rapid single-plate screening assay. A drug-free (negative control) feedingstuff was fortified with the compounds (0-50 mg kg(-1)), extracted by ASE and the extracts applied to the plate at each of three pH ranges - unadjusted extract (pH 5.7-5.9), pH 6.5 and 8.0. At pH 6.5, sub-MIR concentrations of virginiamycin and tylosin were detectable. Avoparcin was detectable at 6.3 mg kg(-1). The detection of zinc bacitracin was#10; pH-independent (10 mg kg(-1)). At pH 8.0, spiramycin was detectable at 5.4 mg kg(-1). Mean +/- SD analytical recoveries from fortified feedingstuffs (n = 10) ranged from 57 +/- 1.5% for avoparcin to 96 +/- 4% for virginiamycin. The five additives were also detectable following ASE extraction from a range of different feedingstuffs fortified with each of the drugs. A further 24 compounds permitted for use in animal feeds were tested. Of these, nine were detectable at their recommended MIR. It is concluded that ASE is a versatile technique suitable for the automated extraction of a range of antimicrobials from animal feedingstuffs. Employing ASE with this single-plate detection system permits the rapid antimicrobial screening of animal feedingstuffs and allows the detection of the banned additives. Whilst the method is applicable as a screening test, more specific postscreening methods would be necessary for subsequent identification (and quantification) of antimicrobials in screening-positive samples.
评估了三种平板系统（指示微生物和生长培养基的组合）用于检测禁用饲料添加剂阿伏帕星、杆菌肽锌、螺旋霉素、泰乐菌素和维吉尼亚霉素的分析标准品。在欧盟获得批准时，每种化合物先前推荐的最低添加率（MIR）为5 mg kg⁻¹。其中一种平板系统（藤黄微球菌ATCC 10240，营养琼脂）检测到了所有五种添加剂。该平板用于进一步研究，评估加速溶剂萃取（ASE）作为快速单平板筛选测定法开发第一步的适用性。用这些化合物（0 - 50 mg kg⁻¹）强化一种无药物（阴性对照）饲料，通过ASE萃取，然后将萃取物在三个pH范围中的每一个范围应用于平板——未调节的萃取物（pH 5.7 - 5.9）、pH 6.5和8.0。在pH 6.5时，可检测到低于MIR浓度的维吉尼亚霉素和泰乐菌素。阿伏帕星在6.3 mg kg⁻¹时可被检测到。杆菌肽锌的检测与pH无关（10 mg kg⁻¹）。在pH 8.0时，螺旋霉素在5.4 mg kg⁻¹时可被检测到。强化饲料（n = 10）的平均 ± 标准差分析回收率范围为阿伏帕星的57 ± 1.5%至维吉尼亚霉素的96 ± 4%。从一系列用每种药物强化的不同饲料中通过ASE萃取后，这五种添加剂也可被检测到。还测试了另外24种允许用于动物饲料的化合物。其中，九种在其推荐的MIR下可被检测到。结论是，ASE是一种通用技术，适用于从动物饲料中自动萃取一系列抗菌剂。将ASE与这种单平板检测系统结合使用，可以对动物饲料进行快速抗菌筛选，并能检测到禁用添加剂。虽然该方法适用于筛选测试，但对于筛选呈阳性的样品，后续鉴定（和定量）抗菌剂需要更具体的筛选后方法。
