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ASTM E2315

Antimicrobial Activity Test using Time-Kill method

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ASTM E2315 : 2016 – Antimicrobial activity using time – kill test

ASTM E2315 is used for evaluating the biocidal activity of an antimicrobial formulation by a time kill test procedure. ASTM E2315 test involves direct inoculation of the microbicidal test sample with the desired test microorganisms. The time kill values are determined by enumerating the surviving microorganism over the course of desired time duration.

ASTM E2315 is a quick test for assessing the biocidal efficacy of disinfectants and topical antiseptics.

ASTM E2315 Test Conditions & Requirement:

The parameters specified by ASTM E2315 standard are as follows :

Test conditions

Mandatory test organisms 

Bactericidal activity




Yeasticidal activity 


Fungicidal activity

Pseudomonas aeruginosa (ATCC 15442)

Staphylococcus aureus (ATCC 6538)

Enterococcus hirae (ATCC 10541)

Escherichia coli (K12) (NCTC 10538) 

Additional strains as per customer request 

Candida albicans (ATCC 10231) 

Saccharomyces Cerevisiae 

Aspergillus brasiliensis (ATCC 16404)

Contact time

15 seconds, 30 seconds, 60 seconds or any time range from several minutes to hours. 


25 °C

Additional temperatures given depending on the intended use of the test product:

Room temperature – 22 °C

Human skin – 30 °C

Warm water – 38 °C

ASTM E2315 Test Method

  • For bacteria, 24 hour old cultures cultivated in nutrient broth are used for experiment. For fungi, spore formation from a saline wash is used.
  • Equal volume of the test product is placed in sterile test vessels.
  • A volume of prepared microbe inoculum (usually 1/10 or less of the product volume) is transferred to the test product vessel and then immediately mixed.
  • After predetermined contact times, a small portion of the mixture is removed and chemically neutralised to quench the antimicrobial activity of the test product.
  • In the next step, neutralising extract is enumerated to determine surviving microorganisms.
  • To determine initial microbial concentration a saline control is inoculated with the same test microbes followed by enumeration.
  • By comparing the initial and final microbe concentration, the log and percentage reduction for each concentration of test product and at each selected time intervals is calculated.
  • The number of microorganisms recovered from the reaction vessel is plotted over time.

Importance of ASTM E2315 Test

ASTM E2315 specifies a test method for evaluating biocidal efficacy of a liquid antimicrobial formulation using time-kill method. Antiseptic handwash used in clinical settings, liquid disinfectants used in the hospitality industry plays an important role in controlling the transmission of microbes. While, mouthwash and feminine wash products maintain an individual’s personal hygiene. Thus, it is essential to test these products for their potency and to study their effect on microorganisms over time.

At Microbe investigations, we assist our customers in identifying the antimicrobial efficacy of their products. Our team of highly qualified microbiologists and chemists perform all the tests in a systematic manner in accordance with the guidelines. Equipped with top-notch instruments and advanced facilities, our labs ensure a meticulous antimicrobial evaluation process by significantly reducing the likelihood of errors.

To discuss your preferred time frame or to get more information on ASTM E2315, please contact us here.


ASTM E2315 is a quantitative suspension-based test method. It used to assess changes in the population of aerobic microorganisms within a specified sampling time when tested against antimicrobial products.

ASTM E2315 standard time-kill test can be used for any liquid finished product, for example, hand sanitizers, antibacterial liquid soaps, mouthwash, feminine wash products, disinfectant cleaning products, etcetera.

The ASTM E2315 test takes 3 – 5 weeks depending on the test organism.

At MIS, we test for ASTM E2315 using the following microbial strains: Pseudomonas aeruginosa (ATCC 15442), Staphylococcus aureus (ATCC 6538), Enterococcus hirae (ATCC 10541), Escherichia coli (K12) (NCTC 10538), Candida albicans (ATCC 10231), Saccharomyces Cerevisiae (ATCC ), Aspergillus brasiliensis (ATCC 16404). Additional strains can be added on customer request,

Contact us for more information

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