EVALUATION OF MICROBIAL INHIBITOR TESTS - THE IDF APPROACH

A guidance for the standardized description of microbial inhibitor tes ts was elaborated by IDF Group 503 ''Antibiotics'' in order to meet th e demands of the complex situation of screening milk for residues of a ntimicrobial residues with respect to fixed detection limits (e.g. max imum residue limits) for an increasing number of substances. The docum ent, which has been accepted as a provisional IDF standard, is intende d to provide a framework and basis for the evaluation of microbial inh ibitor tests, allowing the comparison of data obtained from different examinations and laboratories. Of the numerous items described in the guidance, in this paper the following aspects are dealt with: prerequi sites for experimental work (''negative milk'', test samples, selectio n of concentrations, experimental design for the determination of dete ction limits, evaluation of experimental data), experimental parameter s (variation between test kit batches, shelf life) and remarks concern ing the rating of the elaborated attributes. The ''terms of reference' ' in the mutual consent between producer and user of a certain test sh ould be agreed upon in the context of the guidance.