laboratory diagnostic - testing and comparison - biological samples and assessment reports - quality control - internal - reference strains - qualitative - Escherichia coli, equivalent collections 35218, NCTC 11954, recomended by CLSI, vial x10 discs, keep in the freezer, C.F.U between 10^6-10^9, freeze-dried, water-soluble, used in solid or liquid media, code L37RS1018-10, todylaboratories®