ASTM D4198-20 - Standard Test Methods for Evaluating Absorbent Pads Used with Membrane Filters for Bacteriological Analysis and Growth 

1.1 These test methods cover the determination of the nutrient-holding capacity and the toxic or nutritive effect on bacterial growth of organisms retained on a membrane filter, when the absorbent pad being tested is used as a nutrient reservoir and medium supply source for the retained bacteria.

1.2 The tests described are conducted on 47 mm diameter disks, although other size disks may be employed for bacterial culture techniques.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.