EN 15948:2020

SLOVENSKI STANDARD
01-december-2020
Nadomešča:
SIST EN 15948:2015
Žito - Določevanje vlage in beljakovin - Metoda z uporabo bližnje infrardeče
spektroskopije v celih zrnih
Cereals - Determination of moisture and protein - Method using Near-Infrared-
Spectroscopy in whole kernels
Getreide - Bestimmung der Feuchte und des Proteins - Verfahren der Nahinfrarot-
Spektroskopie bei ganzen Körnern
Céréales - Détermination de la teneur en eau et en protéines - Méthode utilisant la
spectroscopie dans le proche infrarouge sur des grains entiers
Ta slovenski standard je istoveten z: EN 15948:2020
ICS:
67.060 Žita, stročnice in proizvodi iz Cereals, pulses and derived
njih products
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 15948
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2020
EUROPÄISCHE NORM
ICS 67.060 Supersedes EN 15948:2015
English Version
Cereals - Determination of moisture and protein - Method
using Near-Infrared Spectroscopy in whole kernels
Céréales - Détermination de la teneur en eau et en Getreide - Bestimmung der Feuchte und des Proteins -
protéines - Méthode utilisant la spectroscopie dans le Verfahren der Nahinfrarot-Spektroskopie bei ganzen
proche infrarouge sur des grains entiers Körnern
This European Standard was approved by CEN on 21 September 2020.

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-CENELEC 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-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 15948:2020 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Principle . 4
5 Method of analysis . 5
5.1 General. 5
5.2 Near Infrared Instrument . 5
5.3 Prediction models . 5
5.4 Initial validation of the model . 5
5.4.1 General. 5
5.4.2 Initial validation sample set . 6
5.4.3 Initial validation performances . 6
5.5 Update of calibration and validation of new model . 6
6 Sampling . 7
7 Procedure . 7
7.1 Preparation of the test sample . 7
7.2 Measurement . 7
7.3 Local validation of the method . 7
7.4 Periodical adjustment of the instrument . 7
7.5 Checking instrument stability . 7
7.6 Follow up of method performance . 8
8 Calculation and expression of results . 8
9 Accuracy and precision of the method . 8
9.1 Accuracy . 8
9.2 Precision . 9
9.2.1 General. 9
9.2.2 Repeatability . 9
9.2.3 Reproducibility . 9
9.2.4 Critical difference . 10
9.2.5 Application tables . 11
9.2.6 Practical use of precision . 14
9.3 Uncertainty. 14
10 Test report . 14
Bibliography . 15
European foreword
This document (EN 15948:2020) has been prepared by Technical Committee CEN/TC 338 “Cereal and
cereal products”, the secretariat of which is held by AFNOR.
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 April 2021, and conflicting national standards shall be
withdrawn at the latest by April 2021.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 15948:2015.
In comparison with the previous edition, the following technical modifications have been made:
— updating normative references,
— change in the number of validation samples according to the new version of EN ISO 12099:2017,
— precision of the expression of the protein content,
— repeatability and reproducibility determined from 3 interlaboratory tests and addition of
uncertainty according to EN ISO 12099,
— precision about practical use of precision,
— removal of informative annexes concerning 3 interlaboratory tests. All these data being included in
technical report CEN/TR 17474 (Cereals (wheat and barley) - Technical Report of the
interlaboratory studies for the determination of moisture and protein in whole kernels by near
infrared spectroscopy) [1].
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland,
Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United
Kingdom.
Under preparation. Stage at the time of publication: FprCEN/TR 17474.
1 Scope
This document defines a routine method for the determination of moisture and protein contents in whole
kernels of wheat and barley using near infrared spectroscopy in the constituent ranges:
— for wheat:
— moisture content minimum range from 8 % to 22 %;
— protein content minimum range from 7 %DM to 20 %DM.
— for barley:
— moisture content minimum range from 8 % to 22 %;
— protein content minimum range from 7 %DM to 16 %DM.
This document describes the modalities to be implemented by the supplier (5.3 and 5.4) and the user of
the method.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN ISO 12099, Animal feeding stuffs, cereals and milled cereal products - Guidelines for the application of
near infrared spectrometry (ISO 12099)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN ISO 12099 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at http://www.electropedia.org/
4 Principle
The method is based on Near Infrared (NIR) spectroscopy, an indirect, correlative technique to predict
the concentration of various constituents in organic samples. Linear or nonlinear regression modelling is
used to relate NIR spectra to moisture or protein concentrations determined by officially approved
standard methods (e.g. Artificial Neural Network (ANN) regression, Partial Least Squares (PLS)
regression).
5 Method of analysis
5.1 General
According to this document, the method of analysis is defined as the association between a NIR
instrument and a model of prediction or calibration.
5.2 Near Infrared Instrument
Instrument based on diffuse reflectance or transmittance measurement covering the wavelength region
of 700 nm to 2500 nm or segments of this or at selected wavelengths.
5.3 Prediction models
Each model for the prediction of protein and moisture contents in whole grain of wheat and barley is
amongst others characterized by:
— the number of samples used for the calibration (prediction model) development;
— the constituent ranges covered in the model for moisture and protein;
— the factor for calculation of the crude protein content from the total nitrogen content: 5,7 for wheat
or 6,25 for barley taken into account in reference values;
— the expression of the protein result (%DM or as is);
— the temperature range of the samples;
— the number and performance of involved reference laboratories;
— the stability of the model i.e. by number of harvests covered;
— the calibration file defined by its name and its IT name (for example CHECKSUM) insuring its
integrity;
— the seasonal, geographic and genetic variations covered.
5.4 Initial validation of the model
5.4.1 General
Since NIR analysis is an indirect, correlative technique, the results shall be validated against chemical
analysis reference methods. It is important that the reference methods used are officially approved such
as the methods described in the EN ISO standards [2], [3], [4] and [5]. The purpose of validation is to
determine the standard error of prediction (SEP or SEP(C)) which expresses the accuracy of routine NIR
results corrected for the mean difference (bias) between routine NIR and reference method.
The standard error of prediction between chemical analysis methods and predictions shall be compared
to calibration performances specifications and/or historical performances.
5.4.2 Initial validation sample set
The initial validation of a calibration shall be done in accordance with EN ISO 12099 using independent
test sets of wheat and barley samples, originating from different countries and analysed by the reference
methods as [2], [3], [4] or [5].
Requirements for the validation sample set are:
— For each crop species, at least 200 representative samples coming from countries where the model
will be used (20 representative samples min/country) distributed homogeneously over the entire
constituent range;
— the part of the range without any reference sample shall not exceed 0,3 % or %DM;
— the same sample analysed on several instruments or several times on a same device counts for one
sample;
— seasonal effects over at least a three year period, t
...