EN ISO 5495:2007

Sensory analysis - Methodology - Paired comparison test (ISO 5495:2005 and ISO 5495:2005/Cor 1:2006)

ISO 5495:2005 describes a procedure for determining whether there exists a perceptible sensory difference or a similarity between samples of two products concerning the intensity of a sensory attribute. This test is sometimes also referred to as a directional difference test or a 2-AFC test (Alternative Forced Choice). In fact, the paired comparison test is a forced choice test between two alternatives.
The method is applicable whether a difference exists in a single sensory attribute or in several, which means that it enables determination of whether there exists a perceptible difference concerning a given attribute, and the specification of the direction of difference, but it does not give any indication of the extent of that difference. The absence of difference for the attribute under study does not signify that there does not exist any difference between the two products.
This method is only applicable if the products are relatively homogeneous.
The method is effective (1) for determining whether a perceptible difference exists (paired difference test), or whether no perceptible difference exists (paired similarity test) when, for example, modifications are made to ingredients, processing, packaging, handling or storage operations, or (2) for selecting, training and monitoring assessors.
It is necessary to know, prior to carrying out the test, whether the test is a one-sided test (the test supervisor knows a priori the direction of the difference, and the alternative hypothesis corresponds to the existence of a difference in the expected direction) or a two-sided test (the test supervisor does not have any a priori knowledge concerning the direction of the difference, and the alternative hypothesis corresponds to the existence of a difference in one direction or the other).

Sensorische Analyse - Prüfverfahren - Paarweise Vergleichsprüfung (ISO 5495:2005 und ISO 5495:2005/Cor 1:2006)

Diese Internationale Norm beschreibt ein Verfahren zur Bestimmung, ob zwischen den Proben von zwei Prüfmaterialien ein wahrnehmbarer sensorischer Unterschied oder eine Ähnlichkeit in Bezug auf die Intensität einer sensorischen Merkmalseigenschaft vorliegt. Diese Prüfung wird manchmal auch als gerichtete Prüfung auf Unterschied oder 2 AFC-Prüfung (en: Alternative Forced Choice, de: Zwangsauswahl zwischen Alternativen) bezeichnet. Tatsächlich ist die paarweise Vergleichsprüfung eine Zwangsauswahlprüfung (Forced-Choice-Prüfung) zwischen zwei Alternativen.
ANMERKUNG   Die paarweise Vergleichsprüfung ist die einfachste verfügbare Einstufungsprüfung, weil sie sich nur auf zwei Proben bezieht.
Das Verfahren ist unabhängig davon anwendbar, ob der Unterschied nur bei einer einzelnen sensorischen Merkmalseigenschaft oder bei mehreren Merkmalseigenschaften vorliegt; das bedeutet, es ermöglicht die Bestimmung, ob ein wahrnehmbarer Unterschied in Bezug auf eine vorgegebene Merkmalseigenschaft vorliegt, und die Festlegung der Richtung des Unterschieds, es gibt jedoch keinen Hinweis auf die Größe dieses Unterschieds. Das Fehlen eines Unterschieds hinsichtlich der untersuchten Merkmalseigenschaft bedeutet nicht, dass zwischen den beiden Prüfmaterialien kein Unterschied vorliegt.
Dieses Verfahren ist nur anwendbar, wenn die Prüfmaterialien relativ homogen sind.
Das Verfahren eignet sich besonders für
a)   die Untersuchung daraufhin
   ob ein wahrnehmbarer Unterschied vorliegt (paarweise Prüfung auf Unterschied) oder
   ob kein wahrnehmbarer Unterschied vorliegt (paarweise Prüfung auf Ähnlichkeit), wenn zum Beispiel Änderungen bei den Zutaten oder Arbeitsschritten von Verarbeitung, Verpackung, Handhabung oder Lagerung vorgenommen wurde, oder
b)   die Auswahl, Schulung und Leistungsüberprüfung von Prüfpersonen.

Analyse sensorielle - Méthodologie - Essai de comparaison par paires (ISO 5495:2005 et ISO 5495:2005/Cor 1:2006)

L'ISO 5495:2005 décrit un mode opératoire permettant de déterminer s'il existe une différence sensorielle perceptible ou une similitude entre les échantillons de deux produits sur l'intensité d'une propriété sensorielle. Cet essai est parfois également appelé essai de différence directionnel ou essai 2-AFC (Alternative Forced Choice). En effet l'essai de comparaison par paires est un essai à choix forcé entre deux alternatives.
La méthode est applicable s'il existe une différence pour une seule propriété sensorielle ou pour plusieurs, ce qui signifie qu'elle permet de déterminer s'il existe une différence perceptible sur une propriété donnée, de préciser le sens de la différence, mais elle ne donne pas d'indications sur l'amplitude de la différence. L'absence de différence pour l'attribut étudié ne signifie pas qu'il n'existe pas de différence entre les deux produits.
La présente méthode n'est applicable que si les produits sont relativement homogènes.
La méthode est efficace pour (1) déterminer s'il existe (essai par paires de différence), ou s'il n'existe pas de différence perceptible (essai par paires de similitude), quand, par exemple, des modifications sont apportées aux ingrédients, à la transformation, à l'emballage, aux opérations de manutention ou de stockage, ou (2) sélectionner, entraîner et contrôler les sujets.
Il est nécessaire de savoir avant la réalisation de l'essai si l'on se trouve dans un cas d'essai unilatéral (l'expérimentateur a un a priori sur le sens de la différence et l'hypothèse alternative correspond à l'existence d'une différence dans le sens attendu) ou dans un cas d'essai bilatéral (l'expérimentateur n'a pas d'a priori sur le sens de la différence et l'hypothèse alternative correspond à l'existence d'une différence dans un sens ou dans l'autre).
L'essai par paires peut également être utilisé pour comparer deux produits en terme de préférence.

Senzorična analiza - Metodologija - Preskus s primerjavo v parih (ISO 5495:2005 in ISO 5495:2005/Cor 1:2006)

Ta mednarodni standard opisuje postopek za ugotavljanje, ali obstaja zaznavna senzorična razlika oz. podobnost med vzorci dveh izdelkov v smislu intenzitete senzorične lastnosti. Ta preskus se včasih imenuje tudi preskus usmerjene razlike ali preskus 2-AFC (metoda prisilne izbire). Preskus s primerjavo v parih je pravzaprav preskus z uporabo metode prisilne izbire med dvema alternativama. Metoda se lahko uporablja, če obstaja razlika v eni ali več senzorskih lastnostih; to pomeni, da je mogoče ugotoviti, ali obstaja zaznavna razlika, ki zadeva podano lastnost, ter določiti smer razlike, pri čemer podatek o obsegu razlike ni na voljo. Odsotnost razlike za lastnost, ki se preučuje, ne pomeni, da med izdelkoma ne obstaja nobena razlika.

General Information

• Status: Published
• Publication Date: 24-Jul-2007
• Withdrawal Date: 30-Jan-2008
• ICS: 67.240 - Sensory analysis
• Technical Committee: CEN/SS C01 - Food products
• Drafting Committee: CEN/SS C01 - Food products
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 25-Jul-2007
• Due Date: 06-Jul-2008
• Completion Date: 25-Jul-2007
• Ref Project: SIST EN ISO 5495:2007 - Sensory analysis - Methodology - Paired comparison test (ISO 5495:2005 and ISO 5495:2005/Cor 1:2006)

Relations

• Amended By: EN ISO 5495:2007/A1:2016 - Sensory analysis - Methodology - Paired comparison test (ISO 5495:2005/Amd 1:2016)
• Effective Date: 17-Sep-2014

Standards Content (Sample)

SLOVENSKI STANDARD
01-november-2007
6HQ]RULþQDDQDOL]D0HWRGRORJLMD3UHVNXVVSULPHUMDYRYSDULK,62LQ
,62&RU
Sensory analysis - Methodology - Paired comparison test (ISO 5495:2005 and ISO
5495:2005/Cor 1:2006)
Sensorische Analyse - Prüfverfahren - Paarweise Vergleichsprüfung (ISO 5495:2005
und ISO 5495:2005/Cor 1:2006)
Analyse sensorielle - Méthodologie - Essai de comparaison par paires (ISO 5495:2005 et
ISO 5495:2005/Cor 1:2006)
Ta slovenski standard je istoveten z: EN ISO 5495:2007
ICS:
67.240 6HQ]RULþQDDQDOL]D Sensory analysis
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 5495
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2007
ICS 67.240
English Version
Sensory analysis - Methodology - Paired comparison test (ISO
5495:2005 and ISO 5495:2005/Cor 1:2006)
Analyse sensorielle - Méthodologie - Essai de comparaison Sensorische Analyse - Prüfverfahren - Paarweise
par paires (ISO 5495:2005 et ISO 5495:2005/Cor 1:2006) Vergleichsprüfung (ISO 5495:2005 und ISO 5495:2005/Cor
1:2006)
This European Standard was approved by CEN on 12 July 2007.
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
© 2007 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 5495:2007: E
worldwide for CEN national Members.

Foreword
The text of ISO 5495:2005 and ISO 5495:2005/Cor 1:2006 has been prepared by Technical
Committee ISO/TC 34 "Agricultural food products” of the International Organization for
Standardization (ISO) and has been taken over as EN ISO 5495:2007 by Technical Committee
CEN/SS C01 "Food Products", the secretariat of which is held by CMC.

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 January 2008, and conflicting national
standards shall be withdrawn at the latest by January 2008.

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 United
Kingdom.
Endorsement notice
The text of ISO 5495:2005 and ISO 5495:2005/Cor 1:2006 has been approved by CEN as EN
ISO 5495:2007 without any modifications.

INTERNATIONAL ISO
STANDARD 5495
Third edition
2005-11-15
Sensory analysis — Methodology —
Paired comparison test
Analyse sensorielle — Méthodologie — Essai de comparaison par
paires
Reference number
ISO 5495:2005(E)
©
ISO 2005
ISO 5495:2005(E)
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ii © ISO 2005 – All rights reserved

ISO 5495:2005(E)
Contents Page
Foreword. iv
1 Scope . 1
2 Normative references . 2
3 Terms and definitions. 3
4 Principle. 4
5 General test conditions. 4
6 Assessors. 5
6.1 Qualification . 5
6.2 Number of assessors . 5
7 Procedure . 5
8 Analysis and interpretation of results . 6
8.1 When testing for a difference . 6
8.2 When testing for similarity . 6
9 Report . 7
10 Precision and bias . 7
Annex A (normative) Tables. 8
Annex B (informative) Examples . 15
Bibliography . 21

ISO 5495:2005(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 5495 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 12, Sensory
analysis.
This third edition cancels and replaces the second edition (ISO 5495:1983), which has been technically
revised.
iv © ISO 2005 – All rights reserved

INTERNATIONAL STANDARD ISO 5495:2005(E)

Sensory analysis — Methodology — Paired comparison test
1 Scope
This International Standard describes a procedure for determining whether there exists a perceptible sensory
difference or a similarity between samples of two products concerning the intensity of a sensory attribute. This
test is sometimes also referred to as a directional difference test or a 2-AFC test (Alternative Forced Choice).
In fact, the paired comparison test is a forced choice test between two alternatives.
NOTE The paired comparison test is the simplest existing classification test since it concerns only two samples.
The method is applicable whether a difference exists in a single sensory attribute or in several, which means
that it enables determination of whether there exists a perceptible difference concerning a given attribute, and
the specification of the direction of difference, but it does not give any indication of the extent of that difference.
The absence of difference for the attribute under study does not signify that there does not exist any
difference between the two products.
This method is only applicable if the products are relatively homogeneous.
The method is effective
a) for determining
⎯ whether a perceptible difference exists (paired difference test), or
⎯ whether no perceptible difference exists (paired similarity test) when, for example, modifications are
made to ingredients, processing, packaging, handling or storage operations, or
b) for selecting, training and monitoring assessors.
It is necessary to know, prior to carrying out the test, whether the test is a one-sided test (the test supervisor
knows a priori the direction of the difference, and the alternative hypothesis corresponds to the existence of a
difference in the expected direction) or a two-sided test (the test supervisor does not have any a priori
knowledge concerning the direction of the difference, and the alternative hypothesis corresponds to the
existence of a difference in one direction or the other).
The paired test can also be used in order to compare two products in terms of preference. The different cases
of use of the paired test are summarized in Figure 1.
ISO 5495:2005(E)
NOTE Only non-hedonic tests are dealt with in this International Standard.
Figure 1 — Possible different cases of use of the paired comparison test
EXAMPLE 1 (Case a) The production of a biscuit has been modified in order to render it more crisp. It is desired to
check whether this increase is perceptible. Therefore it is necessary to try to highlight a difference to see whether the new
product is perceived as being crispier than the usual product (control).
EXAMPLE 2 (Case b) A manufacturer knows that the product may contain traces of an ingredient which imparts an
off-flavour to the product. He therefore wishes to determine the maximum acceptable quantity so that the flavour
difference with a reference product without this ingredient is barely perceptible and therefore without any regrettable
consequences.
EXAMPLE 3 (Case c) It is desired to produce a new soup and to compare two ingredients which will provide the salty
flavour. For cost-intensive reasons, the ingredient which, at the same concentration, will provide the strongest salty flavour
is sought. Therefore it is necessary to try to highlight a difference. It is not known a priori which ingredient will produce the
strongest salty flavour.
EXAMPLE 4 (Case d) A manufacturer of plastics used, in particular, by car manufacturers for dashboards is seeking,
for economic reasons, to replace the usual lubricant by a new one, but does not wish that the new plastics formula be
perceived as presenting less or more surface slip than the usual one. It is a question of determining whether, for a same
concentration, the new lubricant provides the same “surface slip” level as the usual product. It is necessary to show that
both lubricants are similar in terms of “surface slip”, but it is not known a priori which lubricant can produce the highest
surface slip characteristics.
2 Normative references
The following referenced documents are indispensable for the application 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.
ISO 5492 1992, Sensory analysis — Vocabulary
ISO 6658:1985, Sensory analysis — Methodology — General guidance
ISO 8586-1:1993, Sensory analysis — General guidance for
...