This document specifies general requirements and gives guidance on microbiological examinations. It is applicable to: —     the implementation of specific horizontal or vertical International Standards developed by ISO/TC 34/SC 9 or ISO/TC 34/SC 5 for detection or enumeration of microorganisms, named hereafter “specific standards”; —     good laboratory practices for microbiology laboratories testing samples from the food chain; —     guidance for microbiological laboratories testing samples from the food chain on the technical requirements for conforming to ISO/IEC 17025. The requirements of this general standard supersede corresponding ones in existing specific standards. Additional instructions for examinations using the polymerase chain reaction (PCR) are specified in ISO 22174. This document is applicable to examinations for bacteria, yeasts and moulds and can be used, if supplemented with specific guidance, for parasites and viruses. It does not apply to examinations for toxins or other metabolites (e.g. amines) from microorganisms. This document is applicable to microbiology of the food chain, from primary production stage to food and animal feed products, including the premises where the food or feed production and handling takes place. It is also applicable to the microbiological examination of water where water is used in food production or is regarded as a food in national legislation.