CEN ISO/TS 11133-2:2003
(Main)Microbiology of food and animal feeding stuffs - Guidelines on preparation and production of culture media - Part 2: Practical guidelines on performance testing of culture media (ISO/TS 11133-2:2003)
Microbiology of food and animal feeding stuffs - Guidelines on preparation and production of culture media - Part 2: Practical guidelines on performance testing of culture media (ISO/TS 11133-2:2003)
ISO/TS 11133-2:2003 sets criteria and methods for the performance testing of culture media. It applies to:
commercial bodies producing and/or distributing ready-to-use or semi-finished reconstituted or dehydrated media to microbiological laboratories;
non-commercial bodies supplying media to third parties;
microbiological laboratories preparing culture media for their own use and evaluating the performance of these media.
Mikrobiologie von Lebensmitteln und Futtermitteln - Anleitung für die Vorbereitung und Herstellung von Nährmedien - Teil 2: Praktische Anleitung zur Leistungsprüfung von Nährmedien (ISO/TS 11133-2:2003)
Microbiologie des aliments - Guide pour la préparation et la production des milieux de culture - Partie 2: Guide général pour les essais de performance des milieux de culture (ISO/TS 11133-2:2003)
L'ISO/TS 11133-2:2003 définit des critères et des méthodes pour les essais de performance des milieux de culture. Elle s'applique:
aux entités commerciales qui produisent des milieux prêts à l'emploi, semi-finis reconstitués ou déshydratés et/ou les distribuent aux laboratoires de microbiologie;
aux entités non commerciales qui fournissent des milieux à des tiers;
aux laboratoires de microbiologie qui préparent des milieux de culture pour leur propre usage et qui évaluent les performances de ces milieux.
Mikrobiologija živil in krme - Navodila za pripravo in izdelavo gojišč - 2. del: Praktična navodila za vrednotenje gojišč (ISO/TS 11133-2:2003)
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
01-maj-2004
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3UDNWLþQDQDYRGLOD]DYUHGQRWHQMHJRMLãþ ,6276
Microbiology of food and animal feeding stuffs - Guidelines on preparation and
production of culture media - Part 2: Practical guidelines on performance testing of
culture media (ISO/TS 11133-2:2003)
Mikrobiologie von Lebensmitteln und Futtermitteln - Anleitung für die Vorbereitung und
Herstellung von Nährmedien - Teil 2: Praktische Anleitung zur Leistungsprüfung von
Nährmedien (ISO/TS 11133-2:2003)
Microbiologie des aliments - Guide pour la préparation et la production des milieux de
culture - Partie 2: Guide général pour les essais de performance des milieux de culture
(ISO/TS 11133-2:2003)
Ta slovenski standard je istoveten z: CEN ISO/TS 11133-2:2003
ICS:
07.100.30 Mikrobiologija živil Food microbiology
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
TECHNICAL SPECIFICATION
CEN ISO/TS 11133-2
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
December 2003
ICS 07.100.30
English version
Microbiology of food and animal feeding stuffs - Guidelines on
preparation and production of culture media - Part 2: Practical
guidelines on performance testing of culture media (ISO/TS
11133-2:2003)
Microbiologie des aliments - Guide pour la préparation et la Mikrobiologie von Lebensmitteln und Futtermitteln -
production des milieux de culture - Partie 2: Guide général Anleitung für die Vorbereitung und Herstellung von
pour les essais de performance des milieux de culture Nährmedien - Teil 2: Praktische Anleitung zur
(ISO/TS 11133-2:2003) Leistungsprüfung von Nährmedien (ISO/TS 11133-2:2003)
This Technical Specification (CEN ISO/TS) was approved by CEN on 8 December 2002 for provisional application.
The period of validity of this CEN ISO/TS is limited initially to three years. After two years the members of CEN will be requested to submit
their comments, particularly on the question whether the CEN iSO/TS can be converted into a European Standard.
CEN members are required to announce the existence of this CEN ISO/TS in the same way as for an EN and to make the CEN ISO/TS
available. It is permissible to keep conflicting national standards in force (in parallel to the CEN ISO/TS) until the final decision about the
possible conversion of the CEN ISO/TS into an EN is reached.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2003 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN ISO/TS 11133-2:2003 E
worldwide for CEN national Members.
Contents Page
Foreword. 3
Introduction . 3
1 Scope . 3
2 Normative references . 4
3 Terms and definitions. 4
4 Criteria for routine quality control. 4
5 Methods for use in performance testing of culture media . 7
6 Documentation of test results . 13
Annex A (informative) Example of card for recording test results of culture media prepared by the user
laboratory. 15
Annex B (normative) Recommended test microorganisms for commonly used culture media (giving
information on the culture medium, culture conditions, test microorganisms, culture
collection number of test organisms and the expected reactions). 16
Bibliography . 26
Foreword
This document (CEN ISO/TS 11133-2:2003) has been prepared by Technical Committee CEN/TC 275 “Food
analysis - Horizontal methods”, the secretariat of which is held by DIN, in collaboration with Technical Committee
ISO/TC 34 “Food products”.
This document "Microbiology of food and animal feeding stuffs – Guidelines on preparation and production of
culture media" consist of two parts:
Part 1: General guidelines on quality assurance for the preparation of culture media in the laboratory
Part 2: Practical guidelines on performance testing of culture media
Annex A is informative. Annex B is normative.
This document includes a Bibliography.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this Technical Specification: Austria, Belgium, Czech Republic, Denmark,
Finland, France, Germany, Greece, Hungary Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway,
Portugal, Slovakia, Spain, Sweden, Switzerland and the United Kingdom.
Introduction
It is essential to use culture media of proven quality to carry out microbiological analysis of food reliably. For all
media described in standardized methods it is essential to define the minimum acceptance criteria required to
ensure media reliability. It is recommended that in the determination of the performance characteristics of a culture
medium tests are carried out that conform with this Technical Specification. This applies to:
a) commercially prepared ready-to-use or dehydrated media;
b) culture media prepared from basic constituents in the user’s laboratory.
The establishment of widely accepted minimum performance criteria for media should lead to more consistent
quality of commercially made products and thus reduce the extent of testing necessary in the user’s laboratory.
Furthermore the minimum acceptance criteria measured by the methods defined in this Technical Specification can
be used by all microbiological laboratories to evaluate the productive, selective and/or elective properties of a
culture medium.
In the microbiological analysis of food and animal feeding stuffs the requirements of this Technical Specification
have priority in the assessment of media quality.
1 Scope
This Technical Specification sets criteria and methods for the performance testing of culture media. This Technical
Specification applies to:
commercial bodies producing and/or distributing ready-to-use or semi-finished reconstituted or dehydrated
media to microbiological laboratories;
non-commercial bodies supplying media to third parties;
microbiological laboratories preparing culture media for their own use and evaluating the performance of these
media.
2 Normative references
This Technical Specification incorporates by dated or undated reference, provisions from other publications. These
normative references are cited at the appropriate places in the text and the publications are listed hereafter. For
dated references, subsequent amendments to or revisions of any of these publications apply to this Technical
Specification only when incorporated in it by amendment or revision. For undated references the latest edition of
the publication referred to applies (including amendments).
ENV ISO 11133-1:2000, Microbiology of food and animal feeding stuffs – Guidelines on preparation and production
of culture media – Part 1: General guidelines on quality assurance for the preparation of culture media in the
laboratory (ISO/TR 11133-1:2000).
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ENV ISO 11133-1:2000 apply.
4 Criteria for routine quality control
4.1 General quality criteria
4.1.1 Quality of culture media
The quality of culture media depends on the quality of the basic ingredients, correct formulation, quality of
preparation procedures, elimination of contaminant microbial agents and appropriate packaging and storage
conditions (see ENV ISO 11133-1).
The manufacturer or producer in the laboratory shall comply with the physico-chemical characteristics of the culture
media as specified in the corresponding standard. Furthermore, quality assessment shall ensure that the culture
medium conforms to stated recommendations, including:
distributed quantity and/or thickness;
appearance, colour and homogeneity;
gel consistency;
moisture content;
pH value;
buffering capacity;
microbial contamination.
The individual components and any nutritive or selective supplements shall also undergo suitable quality
assessment procedures.
4.1.2 Quality of basic media components
Culture media described in the International Standards were judged satisfactory; however, due to the variability of
their quality, it may be acceptable for media manufacturers to modify the concentration of some basic biological
ingredients, as listed below:
peptones and meat or yeast extracts variable in their nutritive properties;
agar variable in its gelling properties;
buffering substances;
bile salts, bile extract and desoxycholate, antibacterial dyes, depending on their selective properties;
antibiotics depending on their activity.
4.2 Microbiological quality criteria
4.2.1 General
The microbiological performance tests shall be carried out on a sample which is representative of a batch of end
product.
4.2.2 Microbial contamination
An appropriate quantity, depending on the size of the batch of culture medium, shall be tested for microbial
contamination by incubation under appropriate conditions. Target limits for the percentage of contaminated plates
or containers of liquid medium should be established for each medium or specified by the manufacturer.
Manufacturers should draw up specifications based on media components, processing limits and type of
packaging.
NOTE 1 The samples to be tested should be at least 1 plate or tube or 1 % of plates or tubes from the beginning and 1 plate
or tube or 1 % of plates or tubes from the end of a pouring or dispensing process. The plates or tubes should be incubated for at
least 18 h at 37ºC or under the incubation conditions which are used routinely for this medium according to the specific
standard.
NOTE 2 For statistical sampling plans refer to the ISO 2859-1:1999.
4.2.3 Growth
4.2.3.1 General
To evaluate each batch of complete culture medium, nutrient components or supplements, growth shall be
appropriately assessed by either:
a) quantitative; or
b) semi-quantitative; or
c) qualitative methods.
Quantitative, semi-quantitative or qualitative evaluations shall be performed by the methods described in this
Technical Specification or by another generally accepted technique. For interpretation of the results of testing, it is
necessary to compare the amount of growth on the test medium with that on a reference medium. The use of a
specific reference medium is therefore mandatory for quantitative methods (see the specific standard or Annex B)
For semi-quantitative or qualitative methods, the use of a specific reference medium (see corresponding specific
standard or Annex B) or a culture medium giving a "positive" reaction helps to interpret results. The reference
medium must be of known good quality chosen from a recently released batch, or, if comparing long term stability,
a batch from another supplier,or a ready-to-use medium, etc.
In addition, growth of the target strains shall be typical in appearance, size and morphology of the colonies and
growth of the non-target strains shall be partly or completely inhibited.
4.2.3.2 Productivity
Solid, semi-solid or liquid culture media shall be inoculated with an appropriate inoculum (5.2.1.1) of the working
culture of each of the defined test microorganisms using an appropriate device.
Productivity shall reach a defined minimum limit (see corresponding specific standard or Annex B).
For quantitative methods the Productivity Ratio P (1) is determined as follows:
R
N
S
P = (1)
R
N
O
where
N is the total colony count obtained on the culture medium under test (obtained from one or more plates);
s
N is the total colony count obtained on the defined reference culture medium obtained from one or more
o
plates, and shall be
NOTE The Productivity Ratio of a non selective medium is at least 0,7 for microorganisms that can grow easily on that
medium. The P of the target microorganisms on a selective medium should be at least 0,1. These values are generally
R
achievable, however less rigorous criteria can be accepted for certain combinations of media and test microorganisms (see
corresponding specific standard or Annex B)
For semi-quantitative methods, the scores of consecutive sectors of a plate inoculated by the ecometric technique
are summed to obtain the growth index G , which varies according to the culture medium. It is therefore important
I
to compare them with previous indices and/or G of a reference medium and to ensure that variations are not
I
excessive. The expected range of variations for each culture medium can also be established once sufficient
experience of the method has been gained.
Qualitative evaluations shall be carried out visually by allocating growth scores.
...
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