ASTM E2315-16,Standard Guide for Assessment of Antimicrobial Activity Using a Time-Kill Procedure.
ASTM E2315-16 covers an example of a method that measures the changes in a population of aerobic microorganisms within a specified sampling time when antimicrobial test materials are present.
4. Summary of a Basic Test Method
4.1 The test material or a dilution of the test material is brought into contact with a known population of microorganisms for a specified period of time at a specified temperature.An appropriate and specified neutralization technique is applied to quench the antimicrobial activity of the test material at specified sampling intervals,and the surviving microorganisms are enumerated. The percent and/or log reduction is calculated by comparison with the microbial population.
5. Significance and Use
5.1 This procedure may be used to assess the in vitro reduction of a microbial population of test organisms after exposure to a test material.