Brady M S, Katz S E
Rutgers State University of New Jersey, Cook College, New Brunswick.
J Assoc Off Anal Chem. 1988 Jul-Aug;71(4):717-20.
Results are compared for the microbiological analysis of antibiotics in feeds using the AOAC plate diffusion assay and the simplified 2-plate assay. Five antibiotics, bacitracin, chlortetracycline, oxytetracycline, penicillin, and streptomycin, were used to supplement feed extracts at levels of 100 and 25 micrograms antibiotic/g feed (bacitracin at 100 micrograms/g only). For bacitracin at the one level and for penicillin at both levels, the 2-plate design yielded significantly more accurate results than those of the AOAC assay. The same was true for the 25 micrograms/g level of oxytetracycline and the 100 micrograms/g level of streptomycin. For streptomycin at the 25 micrograms/g supplementation, the AOAC assay results showed better accuracy. There was no significant difference in results between the 2 designs for oxytetracycline at 100 micrograms/g and chlortetracycline at either level. The accuracy and precision of the results for the 2-plate design are equivalent to or better than those obtained using the AOAC design; in addition, the 2-plate assay is less labor-intensive, is more cost-effective, and is able to determine reasonable conditions of similarity.
使用美国官方分析化学师协会（AOAC）平板扩散法和简化的双平板法对饲料中的抗生素进行微生物分析，并对结果进行比较。使用了五种抗生素，即杆菌肽、金霉素、土霉素、青霉素和链霉素，以100微克抗生素/克饲料和25微克抗生素/克饲料的水平添加到饲料提取物中（杆菌肽仅为100微克/克）。对于单一水平的杆菌肽以及两个水平的青霉素，双平板设计产生的结果比AOAC法更准确。对于25微克/克水平的土霉素和100微克/克水平的链霉素也是如此。对于添加量为25微克/克的链霉素，AOAC法的结果显示出更好的准确性。对于100微克/克的土霉素和任一水平的金霉素，两种设计的结果没有显著差异。双平板设计结果的准确性和精密度等同于或优于使用AOAC设计所获得的结果；此外，双平板法劳动强度较低，成本效益更高，并且能够确定合理的相似条件。
