ASTM E1326-15a

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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
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Designation: E1326 − 15 E1326 − 15a
Standard Guide for
Evaluating Non-culture Microbiological Tests Used for
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Enumerating Bacteria
This standard is issued under the fixed designation E1326; 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.
1. Scope
1.1 The purpose of this guide is to assist users and producers of non-culture microbiological tests in determining the
applicability of the test for processing different types of samples and evaluating the accuracy of the results. Culture test procedures
such as the Heterotrophic (Standard) Plate Count, the Most Probable Number (MPN) method and the Spread Plate Count are
widely cited and accepted for the enumeration of microorganisms. However, these methods have their limitations, such as
performance time and degree of accuracy. Moreover time. Moreover, any given culture test method typically recovers only a
fractionportion of the total viable microbes present in a sample. It is these limitations that have recently led to the marketing of
a variety of non-culture procedures, test kits and instruments.
1.2 Culture test methods estimate microbial population densities based on the ability of mircoorganisms in a sample to
proliferate in or on a specified growth medium, under specified growth conditions. Non-culture test methods attempt to provide
the same or complimentary information through the measurement of a different parameter. This guide is designed to assist
investigators in assessing the accuracy and precision of non-culture methods intended for the determination of microbial population
densities or activities.
1.3 It is recognized that the Heterotrophic Plate Count (HPC) does not recover all microorganisms present in a product or a
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system (1, 2). When this problem occurs during the characterization of a microbiological population, alternative standard
enumeration procedures may be necessary, as in the case of sulfate-reducing bacteria. At other times, chemical methods that
measure the rates of appearance of metabolic derivatives, the utilization of contaminated product components or genetic profile
of the microbial population might be indicated. In evaluating non-culture tests, it is possible that the use of these alternative
standard procedures might be the only means available for establishing correlation. In such cases, this guide can serve as a
reference for those considerations.
1.4 Because there are so many types of tests that could be considered non-culture based, it is impossible to recommend a specific
test protocol with statistical analyses for evaluating the tests. Instead, this guide should assist in determining what types of tests
should be considered to verify the utility and identify the limitations of the nonconventional test.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
2. Referenced Documents
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2.1 ASTM Standards:
D1129 Terminology Relating to Water
D4012 Test Method for Adenosine Triphosphate (ATP) Content of Microorganisms in Water
D5245 Practice for Cleaning Laboratory Glassware, Plasticware, and Equipment Used in Microbiological Analyses
D5465 Practice for Determining Microbial Colony Counts from Waters Analyzed by Plating Methods
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E1601 Practice for Conducting an Interlaboratory Study to Evaluate the Performance of an Analytical Method
E2756 Terminology Relating to Antimicrobial and Antiviral Agents
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This guide is under the jurisdiction of ASTM Committee E35 on Pesticides, Antimicrobials, and Alternative Control Agents and is the direct responsibility of
Subcommittee E35.15 on Antimicrobial Agents.
Current edition approved May 1, 2015Oct. 1, 2015. Published June 2015November 2015. Originally approved in 1990. Last previous edition approved in 20132015 as
E1326 – 13.E1326 – 15. DOI: 10.1520/E1326-15.10.1520/E1326-15A.
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The boldface numbers in parentheses refer to the list of references at the end of this guide.
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standa
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