This International Standard gives general guidelines for enumeration and detection of mesophilic aerobic bacteria present in cosmetics, – by counting the colonies on agar medium after aerobic incubation, or – by checking the absence of bacterial growth after enrichment. Because of the large variety of cosmetic products within this field of application, this method may not be appropriate for some products in every detail (e.g. certain water immiscible products). Other methods (e.g. automated) may be substituted for the tests presented here provided that their equivalence has been demonstrated or the method has been otherwise validated. If needed, microorganisms enumerated or detected may be identified using suitable identification tests described in the standards given in the Bibliography. In order to ensure product quality and safety for consumers, it is advisable to perform an appropriate microbiological risk analysis, so as to determine the types of cosmetic products to which this International Standard is applicable. Products considered to present a low microbiological risk include those with low water activity, hydro-alcoholic products, extreme pH values, etc.