This document gives technical requirements and guidance on the establishment or revision of standardized reference methods for the analysis (detection or quantification) of microorganisms in - products intended for human consumption and for the feeding of animals, - environmental samples in the area of food/feed production and food/feed handling, and - samples from the primary production stage. This international document defines the technical stage (or early stage) of the establishment of a new standardized reference method or of the revision of an existing standardized reference method. It includes, in particular, requirements and guidance on the validation of the selected method. This document has been prepared by Technical Committee ISO/TC 34 "Food products", Subcommittee SC 9 "Microbiology", in collaboration with Technical Committee CEN/TC 275, "Food analysis - Horizontal methods", Working Group 6, "Microbiology of the food chain", the secretariat of which is held by AFNOR (France). The committee responsible for this standard is NA 057-01-12 AA "Validierung mikrobiologischer Verfahren" ("Validation of microbiological methods") at DIN Standards Committee Food and Agricultural Products (NAL).