CEN/TR 16324:2012
(Main)Technical report of the interlaboratory study for the determination of Besatz in common wheat, rye and durum wheat
Technical report of the interlaboratory study for the determination of Besatz in common wheat, rye and durum wheat
The term "Besatz" applies to all components of a grain sample that differ from the normal basic cereal. It includes the following groups: broken grains, shrivelled grains, other cereals, grains damaged by pests, grains with discoloured germ, grains overheated during drying, sprouted grains, extraneous seeds, unsound grains, ergot, bunted grains, extraneous matter, husks and impurities of animal origin. The amount of Besatz and its constituent groups is important for health, cleaning, milling and further processing aspects. For these reasons Besatz is a component of contracts in grain trade and also of the grain intervention system of EU. The principle of the determination of Besatz is to separate all the groups of Besatz from the normal basic cereal grains of unimpaired quality by sieving and manual selection out of a subsample and to quantify them. There are various problems in the determination of Besatz: Firstly, the identification of the different groups of Besatz depends strongly on the experience and the knowledge of the investigator. Also experienced investigators can differ in their characterization of grains. Finally, one is faced with the fact that grain, even after mixing, is rarely homogenous. In other words, if a sample was divided by a sample divider into a number of portions, the amount of a specific group of Besatz in each portion could be different, even if absolutely no human or machine error occurred in each determination. These problems will result in variation of the results of the determination.
An international interlaboratory trial for the determination of Besatz in common wheat, durum wheat and rye was accomplished with 15 laboratories in order to get information on the intra- and interlaboratory variability of the determination of Besatz.
The Technical Report here describes the preparation and evaluation of the results of this interlaboratory test.
Technischer Bericht des Ringversuchs zur Bestimmung von Besatz in Weizen, Roggen und Hartweizen
Der Begriff „Besatz“ gilt für alle Bestandteile einer Getreideprobe, die nicht einwandfreies Grundgetreide sind. Er umfasst die folgenden Fraktionen: Bruchkorn, Schmachtkorn, Fremdgetreide, Körner mit Schädlingsfraß, Körner mit Keimverfärbungen, durch Trocknung überhitzte Körner, Auswuchs, Fremdkörner, verdorbene Körner, Mutterkorn, Brandbutten, Verunreinigungen, Spelzen und Verunreinigungen tierischen Ursprungs. Die Menge an Besatz und die zugehörigen Fraktionen der Bestandteile sind für Aspekte von Bedeutung, die sich auf Gesundheit, Reinigung, Vermahlung und Weiterverarbeitung beziehen. Aus diesen Gründen ist Besatz ein Bestandteil von Verträgen im Getreidehandel und auch des Interventionssystems für Getreide der EU. Das Prinzip der Bestimmung von Besatz besteht darin, alle Besatzfraktionen durch Siebung und Handauslese einer Teilprobe von normalem Grundgetreide einwandfreier Qualität abzutrennen und diese Fraktionen quantitativ zu bestimmen. Bei der Bestimmung von Besatz treten verschiedene Probleme auf: Erstens hängt die Identifizierung der verschiedenen Besatzfraktionen stark von der Erfahrung und Kenntnissen des Prüfers ab. Auch erfahrene Prüfer können sich in der Charakterisierung der Körner unterscheiden. Letztendlich ist es eine Tatsache, dass das Getreide selbst nach dem Mischen selten homogen ist. Anders ausgedrückt, wenn eine Probe mit einem Probenteiler in eine Reihe von Anteilen geteilt wird, kann die Menge einer bestimmten Besatzfraktion in jedem Anteil anders sein, selbst wenn bei der Bestimmung absolut kein menschliches Versagen oder Maschinenfehler aufgetreten ist. Diese Probleme führen zu einer Streuung der Ergebnisse der Bestimmung.
Es wurde ein internationaler Ringversuch zur Bestimmung von Besatz in Weizen, Hartweizen und Roggen unter Teilnahme von 15 Laboratorien durchgeführt, um Angaben über die Schwankungen innerhalb eines Laboratoriums und zwischen Laboratorien bei der Bestimmung von Besatz zu erhalten.
Im vorliegenden Technischen Bericht werden die Aufbereitung und Auswertung der Ergebnisse dieses Ringversuchs beschrieben.
Rapport technique relatif à l'essai interlaboratoires portant sur la détermination du pourcentage d'impuretés dans le blé tendre, le seigle et le blé dur
Tehnično poročilo o medlaboratorijski študiji za ugotavljanje primesi v pšenici, rži in pšenici durum
Izraz »primesi« se nanaša na vse sestavine vzorca zrnja, ki se razlikujejo od običajnega osnovnega žita. Vključuje naslednje skupine: lomljena zrna, zakrnela zrna, druga žita, zrna, ki so jih poškodovali škodljivci, zrna z obledelim kalčkom, zrna, ki so se pregrela med sušenjem, nakaljena zrna, tuja semena, nezdrava zrna, rženi rožički, snetljiva zrna, tuje snovi, luskine in nečistoče živalskega izvora. Količina primesi in njenih sestavnih skupin je pomembna za zdravje, čiščenje, mletje in nadaljnje vidike obdelave. Zato so primesi sestavni del pogodb v trgovini z žitom v zrnju in tudi intervencijskega sistema EU za žita v zrnju. Načelo ugotavljanja primesi je ločiti vse skupine primesi od običajnega osnovnega žita v zrnju neoslabljene kakovosti s sejanjem in ročnim prebiranjem podvzorca ter jih količinsko opredeliti. Pri ugotavljanju primesi se pojavljajo različne težave. Opredelitev različnih skupin primesi je na primer močno odvisna od izkušenj in znanja preiskovalca. Tudi izkušeni preiskovalci lahko različno določijo lastnosti zrn. Nenazadnje je treba upoštevati dejstvo, da je zrnje tudi po mešanju redko homogeno. Drugače povedano, če bi se vzorec z razdeljevalnikom vzorca razdelil na več delov, bi se lahko količina določene skupine primesi med posameznimi deli razlikovala, čeprav pri posamezni določitvi zagotovo ni bilo človeške ali strojne napake. Zaradi teh težav bodo rezultati določitev različni. V sodelovanju s 15 laboratoriji se je izvedel mednarodni medlaboratorijski poskus za ugotavljanje primesi v pšenici, pšenici durum in rži, da bi se pridobile informacije o spremenljivosti ugotavljanja primesi znotraj laboratorija in med laboratoriji. Navedeno tehnično poročilo opisuje pripravo in oceno rezultatov tega medlaboratorijskega preskusa.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-oktober-2012
7HKQLþQRSRURþLORRPHGODERUDWRULMVNLãWXGLML]DXJRWDYOMDQMHSULPHVLYSãHQLFLUåL
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Technical report of the interlaboratory study for the determination of Besatz in common
wheat, rye and durum wheat
Technischer Bericht über Ringversuchsergebnisse zur Bestimmung von Besatz in
Weizen, Roggen und Hartweizen
Rapport technique relatif à l'essai interlaboratoire portant sur la détermination du
pourcentage d'impuretés dans le blé tendre, le seigle et le blé dur
Ta slovenski standard je istoveten z: CEN/TR 16324:2012
ICS:
67.060 äLWDVWURþQLFHLQSURL]YRGLL] Cereals, pulses and derived
QMLK products
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
TECHNICAL REPORT
CEN/TR 16324
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
August 2012
ICS 67.060
English Version
Technical report of the interlaboratory study for the
determination of Besatz in common wheat, rye and durum wheat
Rapport technique relatif à l'essai interlaboratoire portant Technischer Bericht des Ringversuchs zur Bestimmung
sur la détermination du pourcentage d'impuretés dans le von Besatz in Weizen, Roggen und Hartweizen
blé tendre, le seigle et le blé dur
This Technical Report was approved by CEN on 7 February 2012. It has been drawn up by the Technical Committee CEN/TC 338.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2012 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 16324:2012: E
worldwide for CEN national Members.
Contents Page
Foreword .3
Introduction .4
1 Scope .5
2 Design of the study.5
3 Statistical evaluation .6
4 Results of the determination of "broken grains" .8
5 Results of the determination of "shrivelled grains" . 11
6 Results of the determination of "other cereals" . 14
7 Results of the determination of "grains damaged by pests" . 17
8 Results of the determination of "grains in which the germ is discoloured, mottled grains" . 20
9 Results of the determination of "sprouted grains" . 23
10 Results of the determination of "extraneous seeds" . 26
11 Results of the determination of "unsound grains" . 29
12 Results of the determination of "extraneous matter" . 32
13 Results of the determination of "husks" . 35
14 Results of the determination of "ergot" . 38
15 Results of the determination of "grain impurities" . 41
16 Results of the determination of "miscellaneous impurities" . 44
17 Results of the determination of "total Besatz" . 47
18 Precision data of sample set A . 50
19 Results of sample set A and B . 54
Annex A (informative) Participants . 59
Bibliography . 60
Foreword
This document (CEN/TR 16324:2012) has been prepared by Technical Committee CEN/TC 338 “Cereal and
cereal products”, the secretariat of which is held by AFNOR.
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.
Introduction
The term “Besatz” applies to all components of a grain sample that differ from the normal basic cereal. The
principle of the determination of Besatz is to separate all the groups of Besatz from the normal basic cereal
grains of unimpaired quality by sieving and manual selection out of a subsample and to quantify them. The
amount of Besatz and its constituent groups is important for health, cleaning, milling and further processing
aspects. For these reasons Besatz is a part of contracts in grain trade and also of the grain intervention
system of the EU. At present a European Standard for the determination of Besatz (EN 15587) has been
developed.
An international interlaboratory test for the determination of Besatz, according to EN 15587 and involving 15
laboratories in 11 countries, was carried out with two common wheat, two rye and two durum wheat samples.
Statistical analysis was possible for all Besatz fractions with the exception of grains overheated during drying,
bunted grains, and impurities of animal origin.
Very high interlaboratory variation was found for the fractions mottled grains (including grains in which the
germ is discoloured), unsound grains, and grains damaged by pests.
The lowest interlaboratory variation was found for the fractions extraneous matter, extraneous seeds, and
ergot.
The coefficient of variability in most cases depended clearly on the amount of the respective Besatz group,
whereby the amount of the respective Besatz group was in a normal range. As a result the coefficient of
intralaboratory variability for the total Besatz was not higher than 10 %. The coefficient of interlaboratory
variability for the total Besatz was not higher than 20 %, provided the amount of mottled grains or unsound
grains or insect-damaged grain is not higher than 1 % (w/w).
1 Scope
The term "Besatz" applies to all components of a grain sample that differ from the normal basic cereal. It
includes the following groups: broken grains, shrivelled grains, other cereals, grains damaged by pests, grains
with discoloured germ, grains overheated during drying, sprouted grains, extraneous seeds, unsound grains,
ergot, bunted grains, extraneous matter, husks and impurities of animal origin. The amount of Besatz and its
constituent groups is important for health, cleaning, milling and further processing aspects. For these reasons
Besatz is a component of contracts in grain trade and also of the grain intervention system of EU. The
principle of the determination of Besatz is to separate all the groups of Besatz from the normal basic cereal
grains of unimpaired quality by sieving and manual selection out of a subsample and to quantify them. There
are various problems in the determination of Besatz: Firstly, the identification of the different groups of Besatz
depends strongly on the experience and the knowledge of the investigator. Also experienced investigators can
differ in their characterization of grains. Finally, one is faced with the fact that grain, even after mixing, is rarely
homogenous. In other words, if a sample was divided by a sample divider into a number of portions, the
amount of a specific group of Besatz in each portion could be different, even if absolutely no human or
machine error occurred in each determination. These problems will result in variation of the results of the
determination.
An international interlaboratory trial for the determination of Besatz in common wheat, durum wheat and rye
was accomplished with 15 laboratories in order to get information on the intra- and interlaboratory variability of
the determination of Besatz.
The Technical Report here describes the preparation and evaluation of the results of this interlaboratory test.
2 Design of the study
Each laboratory received two kinds of sample sets.
The sample set A consisted of six samples which had a mass of not less than 50g. The participants received
two samples of common wheat, rye and durum wheat. The sample set A was prepared from basic cereal of
1)
unimpaired quality. Certain amounts of the 14 different Besatz groups were added to each sample of the set
A, in the way that the two samples of the same cereal had the same composition. The composition of the
spiked samples was chosen to ensure that i) laboratories obtaining outlying results would be identified and ii)
the influence of sample division on the precision of the method would be recognizable.
1) The added material of the various Besatz groups comes from numerous Besatz-investigations of our own laboratory.
The material was reviewed independently by three persons with regard to the unique assignment to a Besatz group.
The sample set B consisted of six samples which had a mass of not less than 1kg. The participants received
two samples of common wheat, rye and durum wheat, resp. The sample set B was prepared from clean basic
2)
cereal, which contained small amounts of Besatz . One bulk sample of slightly more than 40kg of each
cereal (wheat, rye, and durum) was used. After careful mixing to make the bulk sample as homogeneous as
possible it was divided using a sample divider to obtain 40 samples. Twenty of them were directly sealed in
moisture proof plastic bags. The other 20 samples were spiked with certain Besatz groups, individually mixed
and the sealed in moisture proof plastic bags. In this way we achieved different concentration levels of the
various Besatz groups. The concentration levels were selected to represent the range of Besatz commonly
found in grain samples. The results obtained for the sample set B were used for the calculation of the
precision data given in Annex D of EN 15587:2008.
The participants were instructed to analyse the samples of set A only once and the samples of set B in
duplicate. They had to divide the samples of set B to obtain the required size, before testing.
We sent the sample to 20 laboratories and after six weeks we received results of 15 laboratories for each
sample.
The laboratories were instructed to report the weights of the analysed samples as well as of the separated
Besatz groups. In addition, participants should calculate the results in terms of percentage weight. The
obtained results of sample set B showed that the method of calculation was not described clearly enough in
the draft standard. Many laboratories have not taken into account that extraneous matter was removed (by
sieving) before testing the two sub-samples. Only five laboratories performed the calculations in the correct
manner. The results of the other laboratories were recalculated before beginning the statistical evaluation.
3 Statistical evaluation
The statistical evaluation was performed according to ISO 5725-2. This requires the examination of data with
the Cochran and Mandel‘s k test for non homogeneity of variances (5 % and 1 % level) and the examination of
the data with the Grubbs and Mandel‘s h test for deviations of laboratory mean values (5 % and 1 % level).
So, the analysis of the results for consistency and outliers was done by:
numerical outlier tests (Cochran’s test, Grubbs’ test); and
graphical consistency technique (Mandel’s statistics, k and h).
The results obtained for the sample set B are presented in Clause 4 to 17. These results were used for the
calculation of the precision data given in EN 15587. The single results of the duplicate determination and the
calculated precision data (after outlier elimination) are always presented in a table and a figure. The results of
the Mandel’s statistic are presented in a separate figure. Abnormal values can be identified by the comparison
with the critical values which are drawn as lines in the figure.
A value which was straggling (abnormal) according to one of these four statistical tests was removed only if
the following two conditions were met:
a) the precision data without this abnormal values differed significantly from the precision data including it,
so that its elimination gave significantly better values for precision;
b) the elimination of this abnormal value does not have the consequence that the ratio r / R
(repeatability/Reproducibility) reaches the value 1.
2) The use of basic cereal of unimpaired quality was impossible, because the cleaning of 120 kg of grain material by
manu
...
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