ASTM E2315-23 PDF

Full title and description

Standard Guide for Assessment of Antimicrobial Activity Using a Time-Kill Procedure — a concise ASTM guide describing example methods to measure in vitro reductions in microbial populations after exposure to an antimicrobial test material using time‑kill sampling and recovery techniques.

Abstract

This guide (E2315-23) presents an example time‑kill procedure for assessing antimicrobial activity in vitro. It outlines options for organism selection and growth, inoculum preparation, exposure and sampling times, temperatures, neutralization and recovery, and data expression (for example log10 reduction). The document emphasizes that variables must be standardized when converting the guide into a specific test method and that microbiological expertise is required to interpret results and limitations of in vitro testing.

General information

• Status: Current / Active (latest revision issued 2023).
• Publication date: Approved April 1, 2023 (E2315-23, issued 2023).
• Publisher: ASTM International (American Society for Testing and Materials).
• ICS / categories: 07.100.99 (microbiology and related methods).
• Edition / version: E2315-23 (2023 revision).
• Number of pages: 5 pages.

Scope

This guide covers an example method to measure changes in the population of aerobic microorganisms within specified sampling times when exposed to antimicrobial test materials in vitro. It provides procedural options (organism and inoculum selection, sampling schedule, temperatures, neutralization/recovery and controls) and notes the limitations of in vitro comparisons when variables differ. The guide is intended as a framework that laboratories can adapt into specific test methods with fixed conditions.

Key topics and requirements

• Time‑kill sampling and recovery technique for assessing antimicrobial activity.
• Selection and preparation of test organisms and inocula (options and considerations).
• Exposure conditions: contact times, temperatures, and sampling schedule.
• Neutralization/recovery procedures and validation of neutralizers to prevent carryover effects.
• Controls and calculation/reporting of results (e.g., log10 reduction, percent reduction).
• Limitations of in vitro methods and the need for standardized variables when comparing results.
• Requirement for microbiological competence to perform and interpret the procedure safely and correctly.

Typical use and users

Used by microbiology and disinfectant testing laboratories, product developers (disinfectants, antiseptics, preservatives), academic researchers studying antimicrobial efficacy, and regulatory or compliance testing organizations that require demonstration of in vitro antimicrobial activity or comparative screening of materials. Laboratories adapt the guide into specific protocols with fixed variables for routine testing.

Related standards

Related and referenced documents include other ASTM and test method standards addressing neutralizer validation, specific antimicrobial test methods, and fixed‑condition efficacy tests (for example, references cited within E2315 include methods such as E2783 and practices for evaluating inactivators). Previous editions (e.g., E2315-16 and earlier) are superseded by the 2023 revision.

Keywords

time‑kill, antimicrobial activity, in vitro, neutralizer validation, log10 reduction, sampling times, disinfectant testing, E2315-23.

FAQ

Q: What is this standard?

A: ASTM E2315-23 is a Standard Guide titled "Assessment of Antimicrobial Activity Using a Time‑Kill Procedure" that describes example methods for measuring in vitro reductions in microbial populations after exposure to antimicrobial agents.

Q: What does it cover?

A: It covers the time‑kill approach (sampling and recovery), options for organism/inoculum preparation, exposure times and temperatures, neutralization and recovery practices, controls and data expression (for example log10 reduction), and notes limitations of in vitro testing.

Q: Who typically uses it?

A: Microbiology testing laboratories, disinfectant and antiseptic manufacturers, academic and contract research labs, and regulatory testing bodies adapt this guide to develop specific test methods for evaluating antimicrobial efficacy.

Q: Is it current or superseded?

A: The 2023 edition (E2315-23) is the current revision of the guide (approved/issued in 2023) and supersedes prior editions such as E2315-16. Users should reference the E2315-23 document as the official, current text.

Q: Is it part of a series?

A: E2315 is part of ASTM Committee E35 work on pesticides, antimicrobials and alternative control agents (Subcommittee E35.15 on Antimicrobial Agents). It is related to other ASTM practices and test methods that address neutralizer evaluation and fixed‑condition efficacy testing.

Q: What are the key keywords?

A: time‑kill, antimicrobial, in vitro, log10 reduction, neutralizer, percent reduction, disinfectant testing, E2315-23.