This International Standard gives requirements and guidance for the organization of proficiency testing schemes for microbiological examinations of: a) foods and beverages, b) feeding animals, c) environmental samples from food and feed production and handling, and d) primary production stages. This International Standard is also applicable to the microbiological examination of water where water is either used in food production or is regarded as a food in national legislation. This International Standard relates to the technical organization and implementation of proficiency testing schemes, as well as the statistical treatment of results of microbiological examinations. This International Standard is designed for use with ISO/IEC 17043 and ISO 13528, and deals only with areas where specific or additional details are necessary for proficiency testing schemes dealing with microbiological examinations for the areas specified in the first paragraph.