This part of ISO 16140 describes the general principle and the technical protocol (based on orthogonal, factorial studies) for the validation of non-proprietary methods for microbiology of the food chain. This part of ISO 16140 is applicable to the validation of non-proprietary methods used in the analysis (detection or quantification) of microorganisms in ¾ð products intended for human consumption, ¾ð products intended for animal feeding, ¾ð environmental samples in the area of food and feed production, handling, and ¾ð samples from the primary production stage. This part of ISO 16140 is in particular applicable to bacteria and fungi. Some clauses can be applicable to other (micro)organisms or their metabolites, to be determined on a case-by-case-basis. This part of ISO 16140 only applies to the validation of methods that are fully specified with regard to all relevant parameters (including tolerances on temperatures and specifications on culture media) and which have already been optimised.