BS ISO 21322:2020 pdf free.Cosmetics – Microbiology – Testing of impregnated or coated wipes and masks.
The method determines the population of viable microorganisms by enumeration of colonies on a non-selective agar medium and by the presence or absence of specified microorganisms growth after enrichment. The method involves the following steps:selection of the test sample; selection of an appropriate method; recovery of microorganisms; enumeration of the population of viable microorganisms by filtration or plate count method; tests for specified microorganisms by enrichment method. The experimental conditions shall be evaluated to ensure that the method should not affect the viability of microorganisms and the recovery of bioburden from the sample and should include the verification of the efficacy of the neutralization (see Clause 11).In order to ensure product quality and safety for the consumer, an appropriate microbiological risk assessment should be performed to determine the types of cosmetic products to which this document is applicable (see ISO 29621:2017, Table 2). Other methods may be substituted provided that their equivalence has been demonstrated.Plate count method consists of either using a pour plate or spread plate method. Each method consists of the following steps. Prepare the agar plates and diluent using a non-selective agar medium for plating the diluent in which the sample was immersed. Incubate the plates for enumeration and/or detection.Count the number of colonies forming units (CFU) based on the number of aerobic mesophilic microorganisms recovered per unit or g.If Petri dishes, 85 mm to 100 mm in diameter are used, add 1 ml of the diluent and pour 15 ml to 20 ml of the melted agar medium (as specified in ISQ 21149 and ISO 16212) kept in a water bath not to exceed 48 °C. If larger Petri dishes (140 mm in diameter) are used, add no more than 10 ml of diluent in each plate and the appropriate amount of agar medium based on the volume of diluent dispensed. Slowly mix the transferred diluent with the medium, carefully rotating or tilting the plates to sufficiently disperse the agar. Allow the mixture in the Petri dishes to solidify on a horizontal surface at room temperature. Record the volume of diluent plated for each medium V/2 or Vd/2.BS ISO 21322 pdf download.