ASTM D7847-22
(Guide)Standard Guide for Interlaboratory Studies for Microbiological Test Methods
Standard Guide for Interlaboratory Studies for Microbiological Test Methods
SCOPE
1.1 Microbiological test methods present challenges that are unique relative to chemical or physical parameters, because microbes proliferate, die off and continue to be metabolically active in samples after those samples have been drawn from their source.
1.1.1 Microbial activity depends on the presence of available water. Consequently, the detection and quantification of microbial contamination in fuels and lubricants is made more complicated by the general absence of available water from these fluids.
1.1.2 Detectability depends on the physiological state and taxonomic profile of microbes in samples. These two parameters are affected by various factors that are discussed in this guide, and contribute to microbial data variability.
1.2 This guide addresses the unique considerations that must be accounted for in the design and execution of interlaboratory studies intended to determine the precision of microbiological test methods designed to quantify microbial contamination in fuels, lubricants and similar low water-content (water activity
1.3 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.
1.4 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.
General Information
Relations
Buy Standard
Standards Content (Sample)
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.
Designation: D7847 − 22
Standard Guide for
1
Interlaboratory Studies for Microbiological Test Methods
This standard is issued under the fixed designation D7847; 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 (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Microbiologicalparameterspresentanumberofuniquechallengesrelativetochemicalandphysical
test methods apropos of the development of precision and bias terms. A number of these challenges
are discussed in Guide E1326.As a working group (WG) we first grappled directly with some of these
issues during the development of Practice D6974. The drafts balloted at the D02.14 subcommittee
level in February and June 2002, were balloted with the document identified as a Method. Moreover,
the proposed Method was drafted as a harmonized document with the Energy Institute’s (EI) Method
IP385.When the item was balloted at D02 level, members of D02.94 compelled us to change the title
from Method to Practice. The argument was that ASTM Methods list single series of steps that lead
to a measurable result (a bit of data; quantitative, semi-quantitative or qualitative). Because D6974
provides for the selection of different sample volumes (based on the estimated culturable population
density) and different growth media (based on the sub-population to be quantified), it would only be
accepted as an ASTM Practice; not a Method. This issue of performing interlaboratory studies for
culture methods will be discussed below.
Since Practice D6974 was approved, four microbiological test methods have been approved by
ASTM: D7463, D7687, D7978, and D8070.
Because these methods measure the concentration of a biomarker molecule or microorganisms, the
issues that are relevant to ILS are similar to, but somewhat different than those that affect ILS for
2
culture methods. Beckers investigated microbiological test method interlaboratory studies, but
advised several measures that are either impractical for or not relevant to the methods that have been
developed within D02: (1) Freeze inoculated samples after dispensing into portions for shipment to
participating labs; (2) Use a single organisms challenge; (3) Add the challenge microbe to a sample
matrix in which it is likely to proliferate.
This guide will list key issues that must be addressed when designing ILS for Methods intended to
measure the microbial properties of fuels and fuel-associated waters.
1. Scope* 1.1.1 Microbial activity depends on the presence of avail-
able water. Consequently, the detection and quantification of
1.1 Microbiological test methods present challenges that are
microbial contamination in fuels and lubricants is made more
unique relative to chemical or physical parameters, because
complicated by the general absence of available water from
microbes proliferate, die off and continue to be metabolically
these fluids.
active in samples after those samples have been drawn from
their source. 1.1.2 Detectability depends on the physiological state and
taxonomic profile of microbes in samples. These two param-
eters are affected by various factors that are discussed in this
guide, and contribute to microbial data variability.
1
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
1.2 This guide addresses the unique considerations that
Subcommittee D02.14 on Stability, Cleanliness and Compatibility of Liquid Fuels.
must be accounted for in the design and execution of inter-
Current edition approved July 1, 2022. Published August 2022. Originally
approved in 2012. Last previous edition approved in 2017 as D7847 – 17. DOI:
laboratory studies intended to determine the precision of
10.1520/D7847-22.
microbiological test methods designed to quantify microbial
2
Beckers, H. J., “Precision Testing of Standardized Microbiological Methods,”
contamination in fuels, lubricants and similar low water-
Journal of Testing and Evaluation, JTEVA, Vol. 14, No. 6, November 1986, pp.
318–320. content (water activity <0.8) fluids.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
D7847 − 22
4
1.3 This standard does not purport to address all of the 2.2 Energy Institute Standard:
safety concerns, if any, associated with its use. It is the
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7847 − 17 D7847 − 22
Standard Guide for
1
Interlaboratory Studies for Microbiological Test Methods
This standard is issued under the fixed designation D7847; 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 (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Microbiological parameters present a number of unique challenges relative to chemical and physical
test methods apropos of the development of precision and bias terms. A number of these challenges
are discussed in Guide E1326. As a working group (WG) we first grappled directly with some of these
issues during the development of Practice D6974. The drafts balloted at the D02.14 subcommittee
level in February and June 2002, were balloted with the document identified as a Method. Moreover,
the proposed Method was drafted as a harmonized document with the Energy Institute’s (EI) Method
IP 385. When the item was balloted at D02 level, members of D02.94 compelled us to change the title
from Method to Practice. The argument was that ASTM Methods list single series of steps that lead
to a measurable result (a bit of data; quantitative, semi-quantitative or qualitative). Because D6974
provides for the selection of different sample volumes (based on the estimated culturable population
density) and different growth media (based on the sub-population to be quantified), it would only be
accepted as an ASTM Practice; not a Method. This issue of performing interlaboratory studies for
culture methods will be discussed below.
Since Practice D6974 was approved, four microbiological test methods have been approved by
ASTM: D7463, D7687, D7978, and D8070.
Because these methods measure the concentration of a biomarker molecule or microorganisms, the
issues that are relevant to ILS are similar to, but somewhat different than those that affect ILS for
2
culture methods. Beckers investigated microbiological test method interlaboratory studies, but
advised several measures that are either impractical for or not relevant to the methods that have been
developed within D02: (1) Freeze inoculated samples after dispensing into portions for shipment to
participating labs; (2) Use a single organisms challenge; (3) Add the challenge microbe to a sample
matrix in which it is likely to proliferate.
This guide will list key issues that must be addressed when designing ILS for Methods intended to
measure the microbial properties of fuels and fuel-associated waters.
1. Scope*
1.1 Microbiological test methods present challenges that are unique relative to chemical or physical parameters, because microbes
proliferate, die off and continue to be metabolically active in samples after those samples have been drawn from their source.
1.1.1 Microbial activity depends on the presence of available water. Consequently, the detection and quantification of microbial
contamination in fuels and lubricants is made more complicated by the general absence of available water from these fluids.
1
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.14 on Stability Stability, Cleanliness and CleanlinessCompatibility of Liquid Fuels.
Current edition approved June 1, 2017July 1, 2022. Published June 2017August 2022. Originally approved in 2012. Last previous edition approved in 20122017 as
ɛ1
D7847 – 12D7847 – 17. . DOI: 10.1520/D7847-17.10.1520/D7847-22.
2
Beckers, H. J., “Precision Testing of Standardized Microbiological Methods,” Journal of Testing and Evaluation, JTEVA, Vol. 14, No. 6, November 1986, pp. 318–320.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
D7847 − 22
1.1.2 Detectability depends on the physiological state and taxonomic profile of microbes in samples. These two parameters are
affected by various factors that are discussed in this guide, and contribute to microbial data variability.
1.2 This guide addresses the unique considerations that must be accounted for in the design and execution of interlaboratory
studies intended to determine the precision of microbiological test methods designed to quantify microbial contamination in fuels,
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.