title: Microbiological determination of neomycin in feeds: collaborative study.
abstract: A modification of the AOAC microbiological determination of neomycin in feeds was collaboratively studied by 12 laboratories. The official method was modified by substituting a constant salt concentration diluent for the feed extract diluent, preparing the agar medium in tris buffer, and performing the test with a monolayer plating system. Each laboratory performed single assays on 8 samples in a randomized sequence. The samples included duplicates of a cattle and swine feed at 2 different marketed concentrations. The mean recovery across all laboratories was 110.7% of theory with a range of means of 69.4-128.6 across the 12 laboratories. The results of one laboratory and 2 additional values from different laboratories were deemed outliers and excluded from statistical analysis. The statistical analysis gave a confidence interval of +/- 26% for individual assays.
authors.affiliation: Upjohn Co., Kalamazoo, MI 49001.
authors.forename: G L
authors.initials: GL
authors.lastname: Stahl
authors.forename: D D
authors.initials: DD
authors.lastname: Kratzer
authors.forename: C W
authors.initials: CW
authors.lastname: Kasson
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D008828:Microbiological Techniques; D009355:Neomycin / Q000032:analysis*; D013212:Staphylococcus epidermidis / Q000187:drug effects*
chemical_list: D009355:Neomycin