ASTM E1891-97

Standard Guide for Determination of a Survival Curve for Antimicrobial Agents Against Selected Microorganisms and Calculation of a D-Value and Concentration Coefficient

General Information

• Status: Historical
• Publication Date: 09-Jun-1997
• Technical Committee: E35 - Pesticides, Antimicrobials, and Alternative Control Agents
• Drafting Committee: E35.15 - Antimicrobial Agents

Relations

• Replaced By: ASTM E1891-97(2002) - Standard Guide for Determination of a Survival Curve for Antimicrobial Agents Against Selected Microorganisms and Calculation of a D-Value and Concentration Coefficient
• Effective Date: 10-Oct-2002

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact
ASTM International (www.astm.org) for the latest information.
Designation: E 1891 – 97
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Guide for
Determination of a Survival Curve for Antimicrobial Agents
Against Selected Microorganisms and Calculation of a
1
D-Value and Concentration Coefficient
This standard is issued under the fixed designation E 1891; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
A variety of testing procedures have been devised almost from the beginning of disinfection and
antisepsis as disciplines. From the first, there was a recognition of the importance of time and rates
of kill. After many decades and numerous test procedures involving carriers, the approach of
establishing a death rate curve (often described as a survivor curve) is reclaiming its importance in
establishing the basic kinetics of the killing process after exposure to antimicrobial chemicals.
D-values (historically, log death time or decimal reduction time), kill or survivor curves, processing
calculations and rates of kill are discussed in many texts. There is extensive theoretical discussion but
little applied material on how to perform testing to establish kill curves and D-values and associated
calculations.
The guideline form has been selected to permit the inclusion of background information and a
model procedure for determining D-values and their calculation. A related function, the concentration
coefficient (h) can be calculated from a series of D-values calculated for different concentrations of
the test antimicrobial and defines the loss of activity as the material is diluted. This information has
value for application in disinfectants because many are sold to be diluted in use.
Specific procedural details are presented in descriptions of methods routinely used to establish a kill
curve. The user should establish a protocol for the process that best fits their needs.
An experimental kill curve provides data for a calculated D-value derived from test data used to
construct the kill curve.
BACKGROUND
Scientists concerned about antimicrobial testing have debated the value of suspension tests in
contrast to tests using simulant carriers with dried microorganisms. U.S. regulation has been
committed to carrier tests, while Europeans have emphasized suspension tests combined with practical
applied test using materials as carriers on which the disinfectant actually will be used.
The examination of the kinetics of kill for various disinfectants provides basic information on the
activity of antimicrobials. The early history of microbiology reveals a strong momentum directed
toward clarification of these reactions. From the earliest years of microbiology, the ideas of rate-of-kill
and killing reactions as first order reactions (from chemical kinetics) have been involved in the
estimation of antimicrobial activity.
Kronig and Paul (1897) were the early pioneers who developed the concept of bacterial destruction
as a process. They used anthrax spores dried on garnet crystals and assessed the survivors by plating
washings from the garments after treatment with disinfectants. Chick (1908) found that the number of
survivors after disinfectant exposure, when plotted against time of treatment, produced a straight line
that showed similarity to chemical, eqstetimolecular reactions. Distortions in the expected straight-line
reactions were noted by Chick as well as in subsequent investigations. Over the years, the most
common type of deviation from the expected, straight-line survivor curve is a sigmodial one
displaying a shoulder, a lag or delay in logarithmic kill, and ending in distinct tailing, sometimes
indicating a resistant population.
There has been a variety of procedures advanced for accumulating data that can be used to calculate
D-values and construct survivor curves.
Esty and Meyer (1922) introduced the terminology we currently use in relation to bacterial kill
whether for spores, vegetative bacterial cells, or mycobacteria in devising thermal processing to
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NOTICE:¬This¬standard¬has¬either¬been¬superceded¬and¬replaced¬by¬a¬new¬version¬or¬discontinued.¬
Contact¬ASTM¬International¬(www.astm.org)¬for¬the¬latest¬information.¬
E 1891
eliminate Clostidium botulinium in the canning industry. They also devised end-point analysis for
interpretation of the results of heat exposure and for processing calculations. Their procedure involved
sampling multiple tubes or other containers of product
...