EN ISO 20541:2008

Milk and milk products - Determination of nitrate content - Method by enzymatic reduction and molecular-absorption spectrometry after Griess reaction (ISO 20541:2008)

ISO 20541|IDF 197:2008 specifies a method for the determination of the nitrate content of milk and milk products by molecular-absorption spectrometry after Griess reaction (preceded by enzymatic reduction).
The method is, in particular, applicable to whole, partly skimmed, skimmed and dried milk, hard, semi-hard and soft cheeses, processed cheese, whey cheese, caseins, caseinates, dried whey and milk protein concentrates.
The method can be used at contents corresponding to a measured concentration in the sample solution (with blank subtracted) of more than 0,2 mg/l.

Milch und Milcherzeugnisse - Bestimmung des Nitratgehaltes - Verfahren mit enzymatischer Reduktion und Molekülabsorptionsspektrometrie nach Griess-Reaktion (ISO 20541:2008)

Diese Internationale Norm legt ein Verfahren zur Bestimmung des Nitratgehaltes von Milch und Milch¬erzeugnissen durch Molekülabsorptionsspektrometrie nach Griess-Reaktion (mit vorausgehender enzymatischer Reduktion) fest.
Das Verfahren ist insbesondere auf Vollmilch, teilentrahmte Milch, Magermilch und Milchpulver, Hart-, Schnitt- und Weichkäse, Schmelzkäse, Molkenkäse, Caseine, Caseinate, Molkenpulver und Milcheiwei߬konzentrate anwendbar.
Das Verfahren kann bei Gehalten angewendet werden, die einer gemessenen Konzentration der Probenlösung (nach Abzug des Blindwertes) von mehr als 0,2 mg/l entsprechen.

Lait et produits laitiers - Détermination de la teneur en nitrates - Méthode par réduction enzymatique et spectrométrie d'absorption moléculaire après réaction de Griess (ISO 20541:2008)

L'ISO 20541|FIL 197:2008 spécifie une méthode de détermination de la teneur en nitrates du lait et des produits laitiers par spectrométrie d'absorption moléculaire après une réaction de Griess (précédée d'une réduction enzymatique).
Cette méthode s'applique notamment au lait entier, demi-écrémé, écrémé et au lait en poudre; aux fromages à pâte dure, demi-dure, et molle; au fromage fondu, au fromage de lactosérum, aux caséines, aux caséinates, au lactosérum en poudre et aux concentrés de protéine de lait.
La méthode peut s'appliquer aux teneurs en nitrates équivalentes à une concentration mesurée de la solution échantillon (après soustraction correspondant au blanc) supérieure à 0,2 mg/l.

Mleko in mlečni proizvodi - Določevanje nitratov - Metoda z encimsko redukcijo in molekularno absorpcijsko spektrometrijo na osnovi Griessove reakcije (ISO 20541:2008)

General Information

• Status: Published
• Publication Date: 31-Aug-2008
• Withdrawal Date: 30-Mar-2009
• ICS: 67.100.01 - Milk and milk products in general
• Technical Committee: CEN/TC 302 - Milk and milk products - Methods of sampling and analysis
• Drafting Committee: CEN/TC 302 - Milk and milk products - Methods of sampling and analysis
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 04-Jan-2012
• Completion Date: 04-Jan-2012
• Ref Project: SIST EN ISO 20541:2008 - Milk and milk products - Determination of nitrate content - Method by enzymatic reduction and molecular-absorption spectrometry after Griess reaction (ISO 20541:2008)

Standards Content (Sample)

SLOVENSKI STANDARD
01-december-2008
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PROHNXODUQRDEVRUSFLMVNRVSHNWURPHWULMRQDRVQRYL*ULHVVRYHUHDNFLMH,62

Milk and milk products - Determination of nitrate content - Method by enzymatic
reduction and molecular-absorption spectrometry after Griess reaction (ISO 20541:2008)
Milch und Milcherzeugnisse - Bestimmung des Nitratgehaltes - Verfahren mit
enzymatischer Reduktion und Molekülabsorptionsspektrometrie nach Griess-Reaktion
(ISO 20541:2008)
Lait et produits laitiers - Détermination de la teneur en nitrates - Méthode par réduction
enzymatique et spectrométrie d'absorption moléculaire après réaction de Griess (ISO
20541:2008)
Ta slovenski standard je istoveten z: EN ISO 20541:2008
ICS:
67.100.01 0OHNRLQPOHþQLSURL]YRGLQD Milk and milk products in
VSORãQR general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 20541
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2008
ICS 67.100.01
English Version
Milk and milk products - Determination of nitrate content -
Method by enzymatic reduction and molecular-absorption
spectrometry after Griess reaction (ISO 20541:2008)
Lait et produits laitiers - Détermination de la teneur en Milch und Milcherzeugnisse - Bestimmung des
nitrates - Méthode par réduction enzymatique et Nitratgehaltes - Verfahren mit enzymatischer Reduktion
spectrométrie d'absorption moléculaire après réaction de und Molekülabsorptionsspektrometrie nach Griess-
Griess (ISO 20541:2008) Reaktion (ISO 20541:2008)
This European Standard was approved by CEN on 6 August 2008.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, 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
© 2008 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 20541:2008: E
worldwide for CEN national Members.

Contents Page
Foreword.3

Foreword
This document (EN ISO 20541:2008) has been prepared by Technical Committee ISO/TC 34 "Agricultural
food products" in collaboration with Technical Committee CEN/TC 302 “Milk and milk products - Methods of
sampling and analysis” the secretariat of which is held by NEN.
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 March 2009, and conflicting national standards shall be withdrawn at
the latest by March 2009.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 20541:2008 has been approved by CEN as a EN ISO 20541:2008 without any modification.

INTERNATIONAL ISO
STANDARD 20541
IDF
First edition
2008-09-01
Milk and milk products — Determination
of nitrate content — Method by enzymatic
reduction and molecular-absorption
spectrometry after Griess reaction
Lait et produits laitiers — Détermination de la teneur en nitrates —
Méthode par réduction enzymatique et spectrométrie d'absorption
moléculaire après réaction de Griess

Reference numbers
ISO 20541:2008(E)
IDF 197:2008(E)
©
ISO and IDF 2008
ISO 20541:2008(E)
IDF 197:2008(E)
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ii © ISO and IDF 2008 – All rights reserved

ISO 20541:2008(E)
IDF 197:2008(E)
Contents Page
Foreword. iv
Foreword. v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 1
4 Principle. 2
5 Reagents. 2
6 Apparatus . 4
7 Sampling. 5
8 Preparation of test sample. 5
8.1 Dried milk, dried whey and milk protein concentrates . 5
8.2 Caseins and caseinates . 5
8.3 Cheese . 6
8.4 Whey cheese . 6
9 Procedure . 6
9.1 Preparation of the test portion . 6
9.2 Removal of fat and protein . 6
9.3 Reagent blank test. 7
9.4 Determination. 7
9.5 Calibration . 9
10 Calculation and expression of results. 9
10.1 Nitrite (matrix blank) content (see Clause 4, Note 3). 9
10.2 Total nitrite/nitrate content . 9
10.3 Nitrate content. 10
11 Precision. 10
11.1 Interlaboratory testing. 10
11.2 Repeatability. 10
11.3 Reproducibility. 11
12 Test report . 11
Annex A (informative) Interlaboratory trials . 12
Bibliography . 15

ISO 20541:2008(E)
IDF 197:2008(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. 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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. 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 document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 20541⎪IDF 197 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 5,
Milk and milk products, and the International Dairy Federation (IDF). It is being published jointly by ISO and
IDF.
iv © ISO and IDF 2008 – All rights reserved

ISO 20541:2008(E)
IDF 197:2008(E)
Foreword
IDF (the International Dairy Federation) is a non-profit organization representing the dairy sector worldwide.
IDF membership comprises National Committees in every member country as well as regional dairy
associations having signed a formal agreement on cooperation with IDF. All members of IDF have the right to
be represented on the IDF Standing Committees carrying out the technical work. IDF collaborates with ISO in
the development of standard methods of analysis and sampling for milk and milk products.
Draft International Standards adopted by the Action Teams and Standing Committees are circulated to the
National Committees for voting. Publication as an International Standard requires approval by at least 50 % of
the IDF National Committees casting a vote.
Attention is drawn to the possibility that
...