This International Standard specifies guidelines for the preparation of test samples from laboratory samples of animal feeding stuffs, including pet foods. NOTE 1 The guidelines mostly derive from those developed by AAFCO (see Reference ). The guidelines are overruled by special instructions and regulations for sample preparation demanded by specific analysis methods. NOTE 2 Such analysis methods are developed by ISO and CEN. NOTE 3 This International Standard does not include special guidelines for sample preparation for microbiological analysis of microorganisms like yeasts, bacteria and moulds. Nonetheless, for microorganisms which are used as feed additives (probiotics), some important aspects of sample preparation are addressed.