prEN ISO 11133

SLOVENSKI STANDARD
01-september-2025
Nadomešča:
SIST EN ISO 11133:2014
SIST EN ISO 11133:2014/A1:2018
SIST EN ISO 11133:2014/A2:2020
Mikrobiologija v prehranski verigi, živalski krmi in vodi - Priprava, izdelava,
skladiščenje in preskušanje lastnosti gojišč in reagentov (ISO/DIS 11133:2025)
Microbiology of the food chain, animal feed and water - Preparation, production, storage
and performance testing of culture media and reagents (ISO/DIS 11133:2025)
Mikrobiologie der Lebensmittelkette, Futtermittel und Wasser - Vorbereitung,
Herstellung, Lagerung und Leistungsprüfung von Nährmedien und Reagenzien (ISO/DIS
11133:2025)
Microbiologie de la chaîne alimentaire, des aliments pour animaux et de l’eau -
Préparation, production, stockage et essais de performance des milieux de culture et
des réactifs (ISO/DIS 11133:2025)
Ta slovenski standard je istoveten z: prEN ISO 11133
ICS:
07.100.20 Mikrobiologija vode Microbiology of water
07.100.30 Mikrobiologija živil Food microbiology
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/DIS 11133
ISO/TC 34/SC 9
Microbiology of the food chain,
Secretariat: AFNOR
animal feed and water —
Voting begins on:
Preparation, production, storage
2025-06-23
and performance testing of culture
Voting terminates on:
media and reagents
2025-09-15
ICS: 07.100.30; 07.100.20
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
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Reference number
ISO/DIS 11133:2025(en)
DRAFT
ISO/DIS 11133:2025(en)
International
Standard
ISO/DIS 11133
ISO/TC 34/SC 9
Microbiology of the food chain,
Secretariat: AFNOR
animal feed and water —
Voting begins on:
Preparation, production, storage
and performance testing of culture
Voting terminates on:
media and reagents
ICS: 07.100.30; 07.100.20
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
Member bodies are requested to consult relevant national interests in ISO/TC AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
147/SC 4 before casting their ballot to the e-Balloting application.
PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
This document is circulated as received from the committee secretariat.
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2025
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland Reference number
ISO/DIS 11133:2025(en)
ii
ISO/DIS 11133:2025(en)
Contents Page
Foreword .vi
Introduction .viii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 General terms and definitions .2
3.2 Terminology of performance testing .2
3.3 Terminology of culture media .3
3.4 Terminology for test microorganisms .6
3.5 Terminology for reagents and supplements .8
4 Quality assurance management . 8
4.1 Documentation .8
4.1.1 Documentation from manufacturer or producer .8
4.1.2 Delivery acceptance of products .8
4.2 Storage .9
4.2.1 General .9
4.2.2 Quality management and product control of dehydrated culture media and
supplements.9
4.2.3 Quality management and product control of ready‐to‐use culture media .9
4.2.4 Quality management and product control of reagents .9
4.3 Laboratory preparation of culture media and reagents .10
4.3.1 General .10
4.3.2 Quality of basic culture medium components .10
4.3.3 Water .10
4.3.4 Weighing and rehydration .11
4.3.5 Dissolution and dispersion .11
4.3.6 Measurement and adjustment of pH .11
4.3.7 Dispensing .11
4.3.8 Sterilization . . .11
4.3.9 Preparation of supplements . 12
4.4 Storage and shelf-life of prepared culture media and reagents. 12
4.4.1 Commercially supplied culture media and reagents . 12
4.4.2 Laboratory prepared culture media and reagents . 12
4.5 Preparation for use . 13
4.5.1 Melting of agar culture media . 13
4.5.2 De-aeration of culture media .14
4.5.3 Addition of supplements .14
4.5.4 Preparation of solid and semi-solid culture media in Petri dishes .14
4.5.5 Preparation of plated culture media for inoculation .14
4.6 Incubation of solid and semi-solid culture media in Petri dishes . 15
4.7 Disposal of culture media and reagents . 15
5 Test microorganisms for performance testing .15
5.1 General . 15
5.2 Selection of test microorganisms . 15
5.3 Preservation and maintenance of test microorganisms .16
5.3.1 General .16
5.3.2 Test microorganisms from commercial sources .16
5.3.3 Laboratory prepared reference stocks.16
5.3.4 Stock cultures.16
5.3.5 Working cultures .17
5.4 Microorganisms for performance testing .17
5.4.1 General .17
5.4.2 Preparation .17

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ISO/DIS 11133:2025(en)
6 Quality control and performance testing of culture media and reagents .20
6.1 General requirements . 20
6.2 Physical and chemical quality control . 20
6.3 Microbiological quality control. 20
6.3.1 General . 20
6.3.2 Reference culture medium . 20
6.3.3 Microbial contamination .21
6.4 General guidance for microbiological performance testing .21
6.4.1 General .21
6.4.2 Ready‐to‐use culture media . 22
6.4.3 Culture media being prepared from commercially available dehydrated
formulations . 23
6.4.4 Culture media being prepared from basic individual components . 23
6.5 Performance evaluation and interpretation of results .24
6.6 Confirmation culture media and reagents .24
6.6.1 Confirmation culture media .24
6.6.2 Confirmation reagents . 25
7 Methods for performance testing of solid culture media .25
7.1 General . 25
7.2 Methods for quantitative tests . 25
7.2.1 Methods for quantitative tests — Definitions . 25
7.2.2 Quantitative method for productivity of solid culture media . 25
7.3 Testing of culture media used for membrane filtration .27
7.4 Testing of culture media used as contact plates .27
7.4.1 Procedure .27
7.4.2 Interpretation of results .27
7.5 Methods for qualitative tests for determination of productivity and selectivity .27
7.5.1 Qualitative streaking method for determination of productivity and selectivity .27
7.5.2 Determination of specificity . 28
7.5.3 Other qualitative methods for solid culture media . 28
8 Methods for performance testing of liquid culture media.28
8.1 General . 28
8.2 Quantitative tube method for performance testing of liquid enrichment culture media
(dilution to extinction method) . 28
8.2.1 General . 28
8.2.2 Preparation of the dilution series . 29
8.2.3 Procedure for testing the liquid culture medium . 29
8.2.4 Calculation and interpretation of results . 29
8.3 Qualitative tube method for performance testing of selective liquid culture media . 30
8.3.1 General . 30
8.3.2 Procedure . 30
8.3.3 Calculation and interpretation of results .31
8.4 Qualitative single tube method (turbidity) for performance testing of liquid culture
media .31
8.4.1 eneral .31
8.4.2 Procedure .31
8.4.3 Interpretation of results .32
8.5 Multipurpose liquid culture media .32
9 Methods for performance testing of diluents and transport media .32
9.1 General .32
9.2 Method for testing diluents .32
9.2.1 Method for quantitative testing of diluents .32
9.3 Method for testing transport media. 33
9.3.1 General . 33
9.3.2 Method for quantitative testing of liquid transport media . 33
9.3.3 Method for qualitative testing of solid transport media . 33
10 Documentation of test results .34

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ISO/DIS 11133:2025(en)
10.1 Information provided by the manufacturer . 34
10.2 Traceability . 34
Annex A (informative) Designation of the components of culture media and reagents in
International Standards on microbiological analysis of food, animal feed and water.35
Annex B (normative) Preparation of reference stock and working culture .37
Annex C (normative) Flow charts of methods for performance testing . 41
Annex D (informative) Example of card for recording test results of culture media .45
Annex E (normative) Test microorganisms and performance criteria for culture media and
reagents .46
Annex F (normative) Reference culture media .71
Annex G (informative) Use of control charts to monitor quantitative testing of solid culture
media . 74
Annex H (informative) Quality assurance of culture media and reagents— Troubleshooting .80
Annex I (informative) Quantitative testing of liquid culture media .81
Annex J (normative) Definition of microbiological performance tests for standardized culture
media and reagents . .85
Annex K (informative) Guideline for the preparation of standardized test suspensions (inocula)
and preservation by ultra-low freezing .88
Annex L (informative) pH measurement of culture media .100
Annex M (informative) Guideline for the evaluation of buffered peptone water (BPW) .103
Bibliography .110

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ISO/DIS 11133:2025(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non‐governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2. www.iso.org/directives
Attention is drawn to the possibility that some of the elements of this document can be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent
rights identified during the development of the document will be in the Introduction and/or on the ISO list of
patent declarations received. www.iso.org/patents
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO’s adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 9,
Microbiology, in collaboration with Technical Committee ISO/TC 147, Water quality, Subcommittee SC 4,
Microbiological methods, and in collaboration with the European Committee for Standardization (CEN)
Technical Committee CEN/TC 463, Microbiology of the food chain, in accordance with the Agreement on
technical cooperation between ISO and CEN (Vienna Agreement).
Any feedback or questions on this document should first be directed to the user’s national standards body. A
complete listing of these bodies are found at www.iso.org/members.html.
This second version of ISO 11133 cancels and replaces ISO 11133:2014, which has been technically revised,
and incorporates the following:
Inclusion of ISO11133 Amendment 1 (2018)
Inclusion of ISO11133 Amendment 2 (2020)
Exclusion of those culture media (and their performance testing details) which have been now detailed
within individual Standards. Refer to https://committee.iso.org/sites/tc34sc9/home/generalstandards/
content-left-area/culture- media/iso-11133-on-culture-media.html
Amalgamation of Annexes E, F and K for those media and reagents not yet detailed within individual
Standards
Inclusion of new Annex F (normative) Reference culture media
Annex G is now Informative, with new content
Inclusion of new Annex K (informative) Guideline for the preparation of standardized test suspensions (inocula)
and preservation by ultra‐low freezing
Inclusion of new Annex L (informative) pH measurement of culture media
Inclusion of new Annex M (informative) Guideline for the evaluation of buffered peptone water (BPW)
Inclusion of performance testing for contact plates

vi
ISO/DIS 11133:2025(en)
Inclusion of distinguishable target strains
Inclusion of other amendments and improvements as determined through technical committee working groups

vii
ISO/DIS 11133:2025(en)
Introduction
In laboratories carrying out microbiological examinations, the main objectives are to maintain, resuscitate,
grow, detect and/or enumerate a wide variety of microorganisms. Culture media are used in all traditional
microbiological culture techniques and also for many alternative techniques. Many formulae of culture
media are commercially available and many more, designed for specific growth purposes, are described in
the literature.
Many tests and procedures depend upon culture media being capable of providing consistent and
reproducible results. The requirements for culture media can be specific to both the sample and the
microorganisms to be detected. Culture media meeting established performance criteria are therefore a
pre‐requisite for any reliable microbiological work. Sufficient testing should be carried out to demonstrate
a) the acceptability of each batch of culture medium,
b) that the culture medium is "fit for purpose", and
c) that the culture medium can produce consistent results.
These three criteria are an essential part of internal quality control procedures and, with appropriate
documentation, will permit effective monitoring of culture media and contribute to the production of both
accurate and reliable data. For reliable microbiological analysis it is essential to use culture media of proven
quality. For all culture media described in standard methods it is essential to define the minimum acceptance
criteria required to ensure their reliability. It is recommended that in the determination of the performance
characteristics of a culture medium tests are carried out that conform with this International Standard.
Culture Media and reagents: type and criteria vs section of this Standard
The widespread adoption of minimum performance criteria for culture media will lead to products with
more consistent quality and thus reduce the extent of testing necessary in the user’s laboratory.
In addition, the acceptance criteria measured by the methods defined in this International Standard can be
used by all microbiological laboratories to evaluate the productive, selective and/or elective properties of a
culture medium. This includes culture media not described in International Standards, including proprietary
culture media, or other methods.
In the microbiological analysis of food, animal feed, environment and water, the requirements of this
International Standard have precedence in the assessment of culture media quality.
ISO 11133 was published in 2014 and superseded all previous ISO publications and information on culture
media. Amendment 1 (published in 2018) provided corrections and explanations whilst Amendment 2
(published in 2020) described the performance testing of confirmation media and reagents.

viii
ISO/DIS 11133:2025(en)
Since 2014, many standards have been published which contain their own specifications for performance
testing of culture media used in the standard. These specifications are based on ISO 11133 but for technical
reasons, they may include new control strains and/or revised specifications for the
performance testing. All new and revised standards now specify the performance testing of culture media
and reagents including the specification of control strains in the standard itself.
Any information on performance testing of culture media and reagents described in new or revised
standards published since 2014 takes precedence over ISO 11133.
When specific standards are revised and new standards developed, they will include a paragraph for
performance testing of the culture media used in the standard, and will refer to ISO 11133 for detailed
methods (or detailed protocols). To ensure performance testing is to the latest requirements, the ISO
webpage enables a rapid crosscheck between this Standard and the individual food and water Standards
published. Please refer to the link https://committee.iso.org/sites/tc34sc9/home/general-standards/
content-left-area/culture-media/iso-11133-on-culture-media.html, where the spreadsheet link shown will
be updated at least annually.
ix
DRAFT International Standard ISO/DIS 11133:2025(en)
Microbiology of the food chain, animal feed and water —
Preparation, production, storage and performance testing of
culture media and reagents
1 Scope
This International Standard defines terms related to quality assurance of culture media and reagents and
specifies the requirements for the preparation of culture media and reagents intended for the microbiological
analysis of food, animal feed, and samples from the food or feed production environment as well as all kinds
of water.
These requirements are applicable to all categories of culture media and reagents prepared for use in
laboratories performing microbiological analyses.
This document also sets criteria and describes methods for the performance testing of culture media and
reagents.
The document is applicable to end-users, commercial bodies, non-commercial bodies and labs preparing
their own media.
This covers all formats of culture media and reagents.
The principles covered in this Standard, as described above, can be equally applied to the preparation,
storage and performance testing of culture media and reagents (used in the intended analysis as described
above) that are not captured in international Standards; this includes proprietary culture media, or other
methods.
The criteria for the performance of those culture media and reagents will be described within those other
methods or in the manufacturers’ certificates.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 6887, (parts 1-5), Microbiology of the food chain — Preparation of test samples, initial suspension and
decimal dilutions for microbiological examination (including amendments)
ISO 7704, Water quality — Requirements for the performance testing of membrane filters used for direct
enumeration of microorganisms by culture methods
ISO 7218, Microbiology of the food chain — General requirements and guidance for microbiological examinations
ISO 8199, Water quality — General requirements and guidance for microbiological examinations by culture
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
NOTE 1 This clause gives the general definitions relating to quality assurance of culture media and provides
terminology relating to performance testing, culture media and test microorganisms.

ISO/DIS 11133:2025(en)
3.1 General terms and definitions
3.1.1
quality control
part of quality management focused on fulfilling quality requirements
Note 1 to entry: See Reference [1].
3.1.2
batch of culture medium or reagent
lot of culture medium or reagent
homogeneous and fully traceable unit of a culture medium referring to a defined amount of bulk, semi‐
finished product or end product, which is consistent in type and quality and which has been produced within
one defined production period, having been assigned the same batch (or lot) number
Note 1 to entry: This also applies to units produced in or by the user lab
Note 2 to entry: This applies to the unit produced, whether from individual components or from commercial blend.
3.1.3
chromogenic substrate fluorogenic substrate
substrate containing a chromophore/fluorophore group and a substrate utilizable by microorganisms
Note 1 to entry: After splitting the chromogenic/fluorogenic substrate, the chromophore is released, and a coloured
end‐product is visible/detectable, or a fluorophore is released and is visible/detectable using ultraviolet (UV) light.
3.2 Terminology of performance testing
3.2.1
performance of culture medium or reagent
response of a culture medium or reagent to a challenge by test microorganisms under defined conditions
3.2.2
target microorganism
microorganism or group of microorganisms to be detected or enumerated which can be expected to grow
under defined conditions
3.2.3
non‐target microorganism
microorganism that is suppressed by the culture medium and/or conditions of incubation or does not show
expected characteristics of the target microorganism
3.2.4
productivity of culture medium
a measure of the recovery of a target microorganism from the culture medium under defined conditions
3.2.5
selectivity of culture medium
degree of inhibition of a non‐target microorganism on or in a selective culture medium under defined
conditions
3.2.6
electivity of culture medium
specificity of culture medium
demonstration, under defined conditions, that non‐target microorganisms, if able to grow on the culture
medium, do not show the same visual characteristics as target microorganisms

ISO/DIS 11133:2025(en)
3.3 Terminology of culture media
3.3.1
culture medium
formulation of substances, in liquid, semi‐solid or solid form, which contain natural and/or synthetic
constituents intended to support the multiplication, (with or without inhibition of certain microorganisms),
identification or preservation of viability of microorganisms
3.3.2 Culture media classified by composition
3.3.2.1
chemically defined culture medium
culture medium consisting only of chemically defined constituents of known molecular structure and
degree of purity
3.3.2.2
chemically undefined or partially undefined culture medium
culture medium consisting entirely or partly of natural materials, processed or otherwise, the chemical
composition of which is not completely defined
Note 1 to entry: Harmonized designations for various chemically undefined components used in culture media are
specified in Annex A.
3.3.2.3
chromogenic culture medium fluorogenic culture medium
culture medium containing one or more chromogenic/fluorogenic substrates
Note 1 to entry: Chromogenic culture media facilitate the identification of bacteria or fungi by means of defined colour
and morphological characteristics (culture medium typical growth). Fluorogenic culture media require visualization
using a UV lamp. The biochemical reaction products, which are necessary for the efficiency of chromogenic/fluorogenic
culture media, are normally the result of the enzymatic activity of certain microorganisms, which in turn depends
greatly on the precise maintenance of specific conditions (e.g. temperature, pH value, concentrations of substrate).
3.3.3 Culture media classified by physical consistency
3.3.3.1
liquid culture medium
culture medium consisting of an aqueous solution of one or more constituents, such as buffered peptone water
Note 1 to entry: In some cases, solid particles are added to the liquid culture medium, such as cooked meat medium.
Note 2 to entry: Liquid culture media in tubes, flasks or bottles are commonly called “broths”.
3.3.3.2
solid culture medium
semi‐solid culture medium
liquid culture medium containing solidifying substances (e.g. agar‐agar, gelatin) in different concentrations
Note 1 to entry: Due to the worldwide use of culture media solidified with agar‐agar, the shortened term “agar” is
often used synonymously for solid culture media and therefore in connection with nouns, e.g. “Plate Count agar”.
Note 2 to entry: Solid culture media poured into Petri dishes are commonly called “plates”. Solid culture media poured
into tubes or small bottles that are kept in slanted positions while the culture media are solidifying are often called
“slants” or “slopes”. If the culture medium is dispensed to fill the bottom of the container, this forms a “butt”.
3.3.4 Culture media classified according to their use

ISO/DIS 11133:2025(en)
3.3.4.1
transport medium
medium designed to preserve and maintain the viability of microorganisms whilst minimising numerical
change in the time period between sample collection and laboratory processing of the sample
EXAMPLE Stuart or Amies transport medium
3.3.4.2
preservation medium
medium designed to preserve and maintain the viability of microorganisms over an extended period, to
protect them against the adverse influences which can occur during long‐term storage and to allow recovery
after this period
EXAM
...