ISO 6222:1988

INTERNATIONAL ISO
6222
STANDARD
Second edition
1999-05- 15
Water quality - Enumeration of culturable
micro-organisms - Colony count by
inoculation in a nutrient agar culture
medium
- LXnombrement des micro-organismes revivifiables -
Qualitk de I’eau
Comptage des colonies par ensemencement dans un milieu de culture nutritif
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Reference number
ISO 6222: 1999(E)

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ISO 6222: 1999(E)
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. Esch 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 patt in the work. ISO
collaborates closely with the International Electrotechnical Commission
(IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in
the ISOIIEC Directives, Part 3.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
Attention is drawn to the possibility that some of the elements of this
International Standard may be the subject of patent rights. ISO shall not be
held responsible for identifying any or all such patent rights.
International Standard ISO 6222 was prepared by the European
Committee for Standardization (CEN) in collaboration with ISO Technical
Committee TC 147, Water quality, Subcommittee SC 4, Microbiological
mefhods, in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
Throu hout the text of this document, read “. . .this Eu ropean Standard. .” to
g
LL
. .this International Standard.”
mean
This second edition cancels and replaces the first edition (ISO 6222:1988),
which has been technically revised.
0 ISO 1999
All rights reserved. Uniess otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronie or mechanical, including photocopying and
microfilm, without Permission in writing from the publisher.
International Organization for Standardization
Case postale 56 l CH-121 1 Geneve 20 l Switzerland
Internet iso@ isoch
Printed in Switzerland
ii

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@ ISO
ISO 6222: 1999(E)
Foreword
The text of EN ISO 6222:1999 has been prepared by Technical Committee CEN/TC 230 “Water analysis”, the secretariat
of which is held by DIN, in collaboration with Technicai Committee ISOTTC 147 “Water quality”.
This European Standard shall be given the status of a national Standard, either by publication of an identical text or by
endorsement, at the latest by November 1999, and conflicting national Standards shall be withdrawn at the latest by
November 1999.
According to the CEN/CENELEC lnternal Regulations, the national Standards organizations of the following countries
are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France,
Germany, Greece, Iceland, lreland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and
the United Kingdom.
Introduction
Waters of all kinds invariably contain a variety of micro-organisms derived from various sources, such as soil and
Vegetation, and estimation of the Overall numbers provide useful information for the assessment and surveillance of water
quality. Separate counts are usually made of the micro-organisms which are able to grow and form colonies on nutrient
agar media at 36 “C and 22 “C.
Colony counts are useful for assessing the integrity of ground water sources and the efficiency of water treatment
processes such as coagulation, filtration and disinfection and provide an indication of the cleanliness and integrity of the
distribution System. They tan also be used to assess the suitabillty of a supply for the preparation of food and drink,
where the water supply should contain few micro-organisms to avoid contaminating the product with spoilage organisms.
The main value of colony counts lies in the detection of changes from those expected, based on frequent, long term
monitoring. Any sudden increase in the count tan be an early warning of serious pollution and calls for immediate
investigation.
1 Scope
This European Standard specifies a method for the enumeration of culturable micro-organisms in water by counting the
colonies formed in a nutrient agar culture medium after aerobic incubation at 36 “G and 22 “C.
The method is intended to measure the operational efficiency of the treatment process of public drinking water supplies
and for general application to all types of water. lt is particularly applicable to the examination of water intended for
human consumption, including water in closed Containers and to natura1 mineral waters.
2 Normative references
This European Standard incorporates provisions from other publications. These normative references are cited at the
appropriate places in the text and the publications are Iisted thereafter. For dated references, subsequent amendment to
or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or
revision. For undated references the most recent edition of the publication referred to applies.
EN ISO 3696
Specification and test methods (ISO 3696: 1987)
Water for analytical Iaboratory use -
EN ISO 5667-3
Water quality - Sampling - Part 3: Guidance on the preservation and handling of samples (ISO 5667-3:1994)
...