SIST EN ISO 1211:2001

Milk - Determination of fat content - Gravimetric method (Reference method) (ISO 1211:1999)

Milch - Bestimmung des Fettgehaltes - Gravimetrisches Verfahren (Referenzverfahren) (ISO 1211:1999)

Lait - Détermination de la teneur en matiere grasse - Méthode gravimétrique (Méthode de référence) (ISO 1211:1999)

Mleko - Določevanje maščobe - Gravimetrijska metoda (Referenčna metoda) (ISO 1211:1999)

General Information

• Status: Withdrawn
• Publication Date: 30-Nov-2001
• Withdrawal Date: 07-Jun-2010
• ICS: 67.100.10 - Milk and processed milk products
• Technical Committee: KŽP - Agricultural food products
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 08-Jun-2010
• Due Date: 01-Jul-2010
• Completion Date: 08-Jun-2010
• Ref Project: EN ISO 1211:2001 - Milk - Determination of fat content - Gravimetric method (Reference method) (ISO 1211:1999)

Relations

• Replaced By: SIST EN ISO 1211:2010 - Milk - Determination of fat content - Gravimetric method (Reference method) (ISO 1211:2010)
• Effective Date: 01-Sep-2010
• Replaced By: SIST EN ISO 1211:2010 - Milk - Determination of fat content - Gravimetric method (Reference method) (ISO 1211:2010)
• Effective Date: 08-Jun-2022
• Replaces: SIST EN ISO 1211:1998 - Milk - Determination of fat content - Gravimetric method (Reference method) (ISO 1211:1984)
• Effective Date: 01-Dec-2001

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 1211:2001
01-december-2001
1DGRPHãþD
SIST EN ISO 1211:1998
0OHNR'RORþHYDQMHPDãþREH*UDYLPHWULMVNDPHWRGD5HIHUHQþQDPHWRGD,62

Milk - Determination of fat content - Gravimetric method (Reference method) (ISO
1211:1999)
Milch - Bestimmung des Fettgehaltes - Gravimetrisches Verfahren (Referenzverfahren)
(ISO 1211:1999)
Lait - Détermination de la teneur en matiere grasse - Méthode gravimétrique (Méthode
de référence) (ISO 1211:1999)
Ta slovenski standard je istoveten z: EN ISO 1211:2001
ICS:
67.100.10 0OHNRLQSUHGHODQLPOHþQL Milk and processed milk
SURL]YRGL products
SIST EN ISO 1211:2001 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 1211:2001

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SIST EN ISO 1211:2001
EUROPEAN STANDARD
EN ISO 1211
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2001
ICS 67.100.10 Supersedes EN ISO 1211:1995
English version
Milk - Determination of fat content - Gravimetric method
(Reference method) (ISO 1211:1999)
Lait - Détermination de la teneur en matière grasse - Milch - Bestimmung des Fettgehaltes - Gravimetrisches
Méthode gravimétrique (Méthode de référence) (ISO Verfahren (Referenzverfahren) (ISO 1211:1999)
1211:1999)
This European Standard was approved by CEN on 14 June 2001.
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 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 Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, 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
© 2001 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 1211:2001 E
worldwide for CEN national Members.

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SIST EN ISO 1211:2001
EN ISO 1211:2001 (E)
Foreword
The text of the International Standard from Technical Committee ISO/TC 34 "Agricultural food
products" of the International Organization for Standardization (ISO) has been taken over as
an European Standard by 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 replaces EN ISO 1211:1995.
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 February 2002, and conflicting national
standards shall be withdrawn at the latest by February 2002.
According to the CEN/CENELEC Internal 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, Ireland, Italy,
Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United
Kingdom.
Endorsement notice
The text of the International Standard ISO 1211:1999 has been approved by CEN as a
European Standard without any modification.
2

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SIST EN ISO 1211:2001
INTERNATIONAL ISO
STANDARD 1211
Second edition
1999-12-15
Milk — Determination of fat content —
Gravimetric method (Reference method)
Lait — Détermination de la teneur en matière grasse — Méthode
gravimétrique
Reference number
ISO 1211:1999(E)
©
ISO 1999

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SIST EN ISO 1211:2001
ISO 1211:1999(E)
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© ISO 1999
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ii © ISO 1999 – All rights reserved

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SIST EN ISO 1211:2001
ISO 1211:1999(E)
Contents Page
1 Scope .1
2 Normative reference .1
3 Term and definition .1
4 Principle.1
5 Reagents.2
6 Apparatus .2
7 Sampling.3
8 Preparation of test sample.3
9 Procedure .4
9.1 Test portion .4
9.2 Blank tests.4
9.3 Preparation of fat-collecting vessel.5
9.4 Determination.5
10 Calculation and expression of results.7
10.1 Calculation.7
10.2 Expression of results .7
11 Precision.7
11.1 Interlaboratory test .7
11.2 Repeatability.8
11.3 Reproducibility.8
12 Test report .8
Annex A (informative) Notes on procedures .9
Annex B (informative) Alternative procedure using fat-extraction tubes with siphon or wash-bottle
fittings.11
Bibliography.14
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SIST EN ISO 1211:2001
ISO 1211:1999(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. 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 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.
International Standard ISO 1211 was prepared by Technical Committee ISO/TC 34, Agricultural food products,
Subcommittee SC 5, Milk and milk products, in collaboration with the International Dairy Federation (IDF) and
AOAC International, and will also be published by these organizations.
This second edition cancels and replaces the first edition (ISO 1211:1984), which has been technically revised.
Annexes A and B of this International Standard are for information only.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.
iv © ISO 1999 – All rights reserved

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SIST EN ISO 1211:2001
INTERNATIONAL STANDARD ISO 1211:1999(E)
Milk — Determination of fat content — Gravimetric method
(Reference method)
WARNING — The use of this International Standard may involve hazardous materials, operations and
equipment. This standard does not purport to address all the safety problems associated with its use. It is
the responsibility of the user of this standard to establish safety and health practices and determine the
applicability of regulatory limitations prior to use.
1 Scope
This International Standard specifies the reference method for the determination of the fat content of milk. The
method is applicable to raw and processed liquid milk, partly skimmed milk and skimmed milk in which no
appreciable separation or breakdown of fat due to lipolysis has occurred (see note in clause 8).
NOTE When greater accuracy is required for skimmed milk, for instance to establish the operating efficiency of cream
separators, the special method for skimmed products specified in ISO 7208 should be used.
2 Normative reference
The following normative document contains provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, this publication do
not apply. However, parties to agreement based on this International Standard are encouraged to investigate the
possibility of applying the most recent edition of the standard indicated below. For undated references, the latest
edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid
International Standards.
ISO 3889, Milk and milk products — Determination of fat content — Mojonnier-type fat extraction flasks.
3 Term and definition
For the purposes of this International Standard, the following term and definition apply.
3.1
fatcontentofmilk
mass fraction of substances determined by the procedure specified in this International Standard
NOTE The fat content is expressed as a mass fraction, in percent [formerly given as % (m/m)].
4Principle
An ammoniacal ethanolic solution of a test portion is extracted with diethyl ether and light petroleum. The solvents
are removed by distillation or evaporation. The mass of the substances extracted is determined.
NOTE This is usually known as the Röse-Gottlieb principle.
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SIST EN ISO 1211:2001
ISO 1211:1999(E)
5 Reagents
Use only reagents of recognized analytical grade, unless otherwise specified, and distilled or demineralized water
or water of equivalent purity.
The reagents shall leave no appreciable residue when the determination is carried out by the method specified
(see 9.2.2).
5.1 Ammonia solution, containing a mass fraction of NH of approximately 25 % (� = 910 g/l).
3 20
NOTE If ammonia solution of this concentration is not available, a more concentrated solution of known concentration may
be used (see 9.4.1).
5.2 Ethanol (C H OH), or ethanol denatured by methanol, containing a volume fraction of ethanol of at least
2 5
94 %. (See A.5.)
5.3 Congo red solution
Dissolve 1 g of Congo red in water in a 100 ml one-mark volumetric flask (6.14). Dilute to the mark with water.
NOTE The use of this solution, which allows the interface between the solvent and aqueous layers to be seen more clearly,
is optional (see 9.4.2). Other aqueous colour solutions may be used provided that they do not affect the result of the
determination.
5.4 Diethyl ether (C H OC H ), free from peroxides (see A.3), containing no more than 2 mg/kg of antioxidants,
2 5 2 5
and complying with the requirements for the blank test (see 9.2.2, A.1 and A.4).
NOTE The use of diethyl ether could lead to hazardous situations. Due to expected changes in safety regulations studies
are ongoing to replace diethyl ether by another reagent provided that it does not affect the end result of the determination.
5.5 Light petroleum, with any boiling range between 30 °C and 60 °C or, as equivalent, pentane
(CH [CH ] CH ) with a boiling point of 36 °C, complying with the requirements for the blank test (see 9.2.2, A.1
3 2 3 3
and A.4).
NOTE The use of pentane is recommended because of its higher purity and constant quality.
5.6 Mixed solvent
Shortly before use, mix equal volumes of diethyl ether (5.4) and light petroleum (5.5).
6 Apparatus
WARNING — Since the determination involves the use of volatile flammable solvents, all electrical
apparatus employed shall comply with legislation relating to the hazards in using such solvents.
Usual laboratory equipment and, in particular, the following.
6.1 Analytical balance, capable of weighing to the nearest 1 mg, with a readability of 0,1 mg.
6.2 Centrifuge, capable of holding the fat-extraction flasks or tubes (6.6) and capable of spinning at a rotational
–1 –1
frequency of 500 min to 600 min to produce a radial acceleration of 80 g to 90 g at the outer end of the flasks or
tubes.
NOTE The use of the centrifuge is optional but recommended (see 9.4.5).
6.3 Distillation or evaporation apparatus, for distilling the solvents and ethanol from the boiling or conical
flasks, or evaporating from beakers and dishes (see 9.4.12) at a temperature not exceeding 100 °C.
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SIST EN ISO 1211:2001
ISO 1211:1999(E)
6.4 Drying oven, electrically heated, with ventilation port(s) fully open, capable of being maintained at a
temperature of 102 °C� 2 °C throughout its working space.
The oven shall be fitted with a suitable thermometer.
6.5 Water bath, capable of being maintained at a temperature of between 35 °C and 40 °C.
6.6 Mojonnier-type fat-extraction flasks, as specified in ISO 3889.
NOTE It is also possible to use fat-extraction tubes, with siphon or wash-bottle fittings, but then the procedure is different.
The alternative procedure is given in annex B.
The fat-extraction flasks shall be provided with good quality bark corks or stoppers of other material [e.g. silicone
rubber or polytetrafluoroethylene (PTFE)] unaffected by the reagents used. Bark corks shall be extracted with the
diethyl ether (5.4), kept in water at a temperature of 60 °C or more for at least 15 min, and shall then be allowed to
cool in the water so that they are saturated when used.
6.7 Rack, for holding the fat-extraction flasks (or tubes) (6.6).
6.8 Wash bottle, suitable for use with the mixed solvent (5.6).
A plastics wash bottle shall not be used.
6.9 Fat-collecting vessels, such as boiling flasks (flat-bottomed), of capacities 125 ml to 250 ml, conical flasks,
of capacity 250 ml, or metal dishes.
If metal dishes are used, they shall be of stainless steel, flat-bottomed with a diameter of 80 mm to 100 mm and a
height of approximately 50 mm.
6.10 Boiling aids, fat-free, of non-porous porcelain or silicon carbide (optional when metal dishes are used).
6.11 Measuring cylinders, of capacities 5 ml and 25 ml.
6.12 Pipettes, graduated, of capacity 10 ml.
6.13 Tongs, made of metal, for holding flasks, beakers or dishes.
6.14 Volumetric flask, one-mark, of capacity 100 ml.
7 Sampling
Sampling is not part of the method specified in this International Standard. A recommended sampling method is
given in ISO 707.
It is important that the laboratory receive a sample which is truly representative and has not been damaged or
changed during transport or storage.
Store the samples at a temperature of between 2 °C and 6 °C from the time of sampling.
8 Preparation of test sample
Warm the test sample to a temperature of between 35 °C and 40 °C by means of the water bath (6.5). Gently mix
the test sample thoroughly by repeatedly inverting the sample bottle without causing frothing or churning. Cool the
test sample quickly to approximately 20 °C. Do not cool test samples of churned milk as these samples have to be
weighed at a temperature of between 30 °C and 40 °C (see 9.1).
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SIST EN ISO 1211:2001
ISO 1211:1999(E)
If a homogeneous test sample can be obtained without prewarming to between 35 °C and 40 °C (e.g. for samples
of skimmed milk), the following procedure should be followed.
Bring the test sample to a temperature of 20 °C. Mix thoroughly to ensure a homogeneous mixture of the fat
throughout the test sample. Do not agitate so vigorously as to cause frothing of the milk or churning of the butterfat.
NOTE A reliable value for the fat content cannot be expected:
a) if the milk is churned;
b) when a distinct smell of free fatty acids is perceptible;
c) if during or after preparation of the test sample, white particles are visible on the walls of the sample bottle or fat droplets
float on the surface of the sample.
9 Procedure
NOTE 1 If it is required to check whether the repeatability limit (11.2) is met, carry out two single determinations in
accordance with 9.1 to 9.4.
NOTE 2 An alternative procedure using fat-extraction tubes with siphon or wash-bottle fittings (see note in 6.6) is given in
annex B.
9.1 Test portion
Mix the test sample (clause 8) by gently inverting the bottle three or four times. Immediately weigh, to the nearest
1 mg, 10 g to 11 g of the test sample, directly or by difference, in a fat-extraction flask (6.6).
Transfer the test portion as completely as possible into the lower (small) bulb of the fat-extraction flask.
9.2 Blank tests
9.2.1 Blank test for method
Carry out a blank test simultaneously with the determination using the same procedure and same reagents, but
replacing the test portion in 9.4.1 by 10 ml of water (see A.2).
If the value obtained in the blank test regularly exceeds 1,0 mg, check the reagents if this has not been recently
done (9.2.2). Corrections of more than 2,5 mg should be mentioned in the test report.
9.2.2 Blank test for reagents
To test the quality of the reagents, carry out a blank test as specified in 9.2.1. Additionally use an empty fat-
collecting vessel, prepared as specified in 9.3, for mass control purposes. The reagents shall leave no residue
greater than 1,0 mg (see A.1).
If the residue of the complete reagent blank test is greater than 1,0 mg, determine the residue of the solvents
separately by distilling 100 ml of the diethyl ether (5.4) and light petroleum (5.5), respectively. Use an empty fat-
collecting vessel, prepared for control purposes as described above, to obtain the real mass of residue which shall
not exceed 1,0 mg.
Very occasionally, the solvents may contain volatile matter which is strongly retained in fat. If there are indications
of the presence of such substances, carry out blank tests on all the reagents and for each solvent using a fat-
collecting vessel with about 1 g of anhydrous butterfat. If necessary, redistil solvents in the presence of 1 g of
anhydrous butterfat per 100 ml of solvent. Use the solvents only shortly after the redistillation.
Replace unsatisfactory reagents, solvents, or redistil solvents.
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SIST EN ISO 1211:2001
ISO 1211:1999(E)
9.3 Preparation of fat-collecting vessel
Dry a fat-collecting vessel (6.9) with a few boiling aids (6.10) in the oven (6.4) set at 102 °C for 1 h.
NOTE 1 Boiling aids are desirable to promote gentle boiling during the subsequent removal of solvents, especially when
using glass fat-collecting vessels; their use is optional with metal dishes.
Protect the fat-collecting vessel from dust and allow it to cool to the temperature of the weighing room (glass fat-
collecting vessel for at least 1 h; metal dish for at least 30 min).
NOTE 2 The fat-collecting vessel should not be placed in a desiccator to avoid insufficient cooling or unduly long cooling
times.
Use tongs (6.13) to place the fat-collecting vessel on the balance. Weigh the fat-collecting vessel to the nearest
1,0 mg.
NOTE 3 Tongs should preferably be used to avoid, in particular, temperature variations.
9.4 Determination
9.4.1 Carry out the determination without delay.
Add 2 ml of ammonia solution (5.1) to the test portion in the fat-extraction flask (9.1), or an equivalent volume of a
more concentrated ammonia solution (see note in 5.1). Mix thoroughly with the test portion in the small bulb of the
fat-extraction flask.
9.4.2 Add 10 ml of ethanol (5.2). Mix gently but thoroughly by allowing the contents of the fat-extraction flask to
flow backwards and forwards between the small and large bulb. Avoid bringing the liquid too near to the neck of the
flask. If desired, add 2 drops of the Congo red solution (5.3).
9.4.3 Add 25 ml of diethyl ether (5.4). Close the fat-extraction flask with a cork saturated with water or with a
stopper of other material wetted with water (6.6). Shake the flask vigorously for 1 min, but not excessively to avoid
the formation of persistent emulsions.
While shaking, keep the fat-extraction flask in a horizontal position with the small bulb extending upwards,
periodically allowing the liquid to run from the large bulb into the small bulb. If necessary, cool the flask in running
water to about room temperature. Carefully remove the cork or stopper and rinse it and the neck of the flask with a
little mixed solvent (5.6). Use the wash bottle (6.8) so that the rinsings run into the flask.
9.4.4 Add 25 ml of the light petroleum (5.5). Close the fat-extraction flask with the rewetted (by dipping into
water) cork or stopper. Mix gently again for 30 s as described in 9.4.2. Proceed with shaking as described in 9.4.3.
9.4.5 Centrifuge (6.2) the closed fat-extraction flask for between 1 min and 5 min at a radial acceleration of 80 g
to 90 g. If a centrifuge is not available, allow the closed flask to stand in the rack (6.7) for at least 30 min until the
supernatant layer is clear and distinctly separated from the aqueous layer. If necessary, cool the flask in running
water, to room temperature.
9.4.6 Carefully remove the cork or stopper and rinse it and the inside of the neck of the fat-extraction flask with a
little mixed solvent (5.6). Use the wash bottle (6.8) so that the rinsings run into the flask. If the interface is below the
bottom of the stem of the flask, raise it slightly above this level by gently adding water down the side of the flask
(see Figure 1) to facilitate the decanting of solvent.
NOTE In Figures 1 and 2, one of the three types of fat-extraction flasks as specified in ISO 3889 has been chosen, but this
does not imply any preference over other types.
9.4.7 Hold the fat-extraction flask by the small bulb and carefully decant as much as possible of the supernatant
layer into the prepared fat-collecting vessel (see 9.3) containing a few boiling aids (6.10) in the case of a boiling or
conical flask (optional with metal dishes). Avoid decanting any of the aqueous layer (see Figure 2).
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SIST EN ISO 1211:2001
ISO 1211:1999(E)
9.4.8 Rinse the outside of the neck of the fat-extraction flask with a little mixed solvent (5.6). Collect the rinsings
in the fat-collecting vessel. Take care that the mixed solvent does not spread over the outside of the fat-extraction
flask. If desired, remove the solvent or a part of it from the fat-collecting vessel by distillation or evaporation as
described in 9.4.12.
9.4.9 Add 5 ml of ethanol (5.2) to the contents of the fat-extraction flask. Using the ethanol, rinse the inside of the
neck of the flask and mix as described in 9.4.2.
Key Key
1 Solvent 1 At second and third extraction
2 At second and third extraction 2 At first extraction
3 At first extraction 3 Aqueous layer
4 Interface 4 Interface
5 Aqueous layer
Figure 1 — Before decanting Figure 2 — After decanting
9.4.10 Carry out a second extraction by repeating the operations described in 9.4.3 to 9.4.7 inclusive. Instead of
25 ml, use only 15 ml of diethyl ether (5.4) and 15 ml of light petroleum (5.5). Using the diethyl ether, rinse the
inside of the neck of the fat-extraction flask too.
If necessary, raise the interface slightly to the middle of the stem of the flask by gently adding water down the side
of the flask (see Figure 1) to enable the final decantation of solvent to be as complete as possible (see Figure 2).
9.4.11 Carry out a third extraction without addition of ethanol by again repeating the operations described in 9.4.3
to 9.4.7 inclusive. Again, use only 15 ml of diethyl ether (5.4) and 15 ml of light petroleum (5.5). Using the diethyl
ether, rinse the inside of the neck of the fat-extraction flask again.
If necessary, raise the interface slightly to the middle of the stem of the flask by gently adding water down the side
of the flask (see Figure 1) to enable the final decanting of solvent to be as complete as possible (see Figure 2).
NOTE The third extraction may be omitted for milk with a fat content of less than 0,5 %.
9.4.12 Remove the solvents (including the ethanol) as completely as possible from the fat-collecting vessel by
distillation if using a boiling or conical flask, or by evaporation if using a beaker or dish (6.3). Rinse the inside of the
neck of the conical flask with a little mixed solvent (5.6) before commencing the distillation.
9.4.13 Heat the fat-collecting vessel, with the boiling or conical flask placed on its side to allow solvent vapour to
escape, for 1 h in the drying oven (6.4) set at 102 °C. Remove the fat-collecting vessel from the oven and
immediately verify whether or not the fat is clear. If the fat is not clear, fatty extraneous matter is presumed to be
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SIST EN ISO 1211:2001
ISO 1211:1999(E)
present and the whole procedure shall be repeated. If the fat is clear, protect the fat-collecting vessel from dust and
allow the fat-collecting vessel to cool (preferably not in a desiccator) to the temperature of the weighing room (a
glass fat-collecting vessel for at least 1 h, a metal dish for at least 30 min).
Do not wipe the fat-collecting vessel immediately before weighing. Use tongs (6.13) to place the fat-collecti
...