1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationSensory analysis Methodology Guidelines for monitoring the performanceof a quantitative sensory panelBS ISO 11132:2012National forewordThis British Standard is the UK implementat
2、ion of ISO 11132:2012.The UK participation in its preparation was entrusted to Technical CommitteeAW/12, Sensory analysis.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisions of acon
3、tract. Users are responsible for its correct application. The British Standards Institution 2012Published by BSI Standards Limited 2012ISBN 978 0 580 66631 5ICS 67.240Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authori
4、ty of the StandardsPolicy and Strategy Committee on 30 November 2012.Amendments issued since publicationAmd. No. Date Text affectedBRITISH STANDARDBS ISO 11132:2012 ISO 2012Sensory analysis Methodology Guidelines for monitoring the performance of a quantitative sensory panelAnalyse sensorielle Mthod
5、ologie Lignes directrices pour le contrle de la performance dun jury sensoriel quantitatifINTERNATIONAL STANDARDISO11132First edition2012-11-01Reference numberISO 11132:2012(E)BS ISO 11132:2012ISO 11132:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All rights reserved. U
6、nless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester.ISO
7、 copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 11132:2012ISO 11132:2012(E) ISO 2012 All rights reserved iiiContents PageForeword iv1 Scope 12 Normative references . 13 Terms and definit
8、ions . 14 Principle . 25 Experimental conditions . 46 Qualification of assessors 47 Procedure 47.1 Monitoring via formal performance validation 47.2 Statistical analysis of data from formal performance validation (a single session) . 57.3 Overall panel performance from formal performance validation
9、. 67.4 Individual assessor performance from formal performance validation . 77.5 Performance issues 97.6 Monitoring via routine product profiling . 97.7 Experimental design for study of performance over time . 97.8 Statistical analysis of data over time . 97.9 Reproducibility between panels 107.10 S
10、tatistical analysis of complete profiles .10Annex A (informative) Example of practical application 11Annex B (informative) Example of use of cusum analysis 18Annex C (informative) Example of use of Shewhart chart .21Bibliography .23BS ISO 11132:2012ISO 11132:2012(E)ForewordISO (the International Org
11、anization 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 establi
12、shed 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 standardizatio
13、n.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. Pu
14、blication 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
15、 rights.ISO 11132 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 12, Sensory analysis.iv ISO 2012 All rights reservedBS ISO 11132:2012INTERNATIONAL STANDARD ISO 11132:2012(E)Sensory analysis Methodology Guidelines for monitoring the performance of a quantitative sensor
16、y panel1 ScopeThis International Standard gives guidelines for monitoring and assessing the overall performance of a quantitative descriptive panel and the performance of each member.A panel of assessors can be used as an instrument to assess the magnitude of sensory attributes.Performance is the me
17、asure of the ability of a panel or an assessor to make valid attribute assessments across the products being evaluated. It can be monitored at a given time point or tracked over time. Performance comprises the ability of a panel to detect, identify, and measure an attribute, use attributes in a simi
18、lar way to other panels or assessors, discriminate between stimuli, use a scale properly, repeat their own results, and reproduce results from other panels or assessors.The methods specified allow the consistency, repeatability, freedom from bias and ability to discriminate of panels and assessors t
19、o be monitored and assessed. Monitoring and assessment of agreement between panel members is also covered. Monitoring and assessment can be carried out in one session or over time.Monitoring performance data enables the panel leader to improve panel and assessor performance, to identify issues and r
20、etraining needs or to identify assessors who are not performing well enough to continue participating.The methods specified in this International Standard can be used by the panel leader to appraise continuously the performance of panels or individual assessors.This International Standard applies to
21、 individuals or panels in training as well as for established panels.2 Normative referencesThe 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 doc
22、ument (including any amendments) applies.ISO 5492, Sensory analysis VocabularyISO 8586, Sensory analysis General guidelines for the selection, training and monitoring of selected and expert assessorsISO 8589, Sensory analysis General guidance for the design of test rooms3 Terms and definitionsFor th
23、e purposes of this document, the terms and definitions given in ISO 5492 and the following apply.3.1agreementability of different panels or assessors to assign similar scores on a given attribute to samples of the same product3.2homogeneitymeasure of the agreement of responses among individual asses
24、sors within a test session, as a panel of assessors in replicate sessions, or for an individual assessor in replicate sessions ISO 2012 All rights reserved 1BS ISO 11132:2012ISO 11132:2012(E)3.3assessor biastendency of an assessor to give scores which are consistently above or below the true score w
25、hen that is known or the panel mean when it is not3.4outlieran assessment that does not conform to the overall pattern of the data or is extremely different from other assessments of the same or similar products3.5panel driftphenomenon where a panel, over time, changes in sensitivity or becomes susc
26、eptible to biases and as a consequence changes the location on the scale where an attribute is rated for a constant, reference product3.6performanceability of a panel or an assessor to make valid and reliable assessments of stimuli and stimulus attributes3.7repeatabilityagreement in assessments of e
27、quivalent product samples under the same test conditions by the same assessor or panel3.8reproducibilityagreement in assessments of equivalent product samples under different test conditions, with different tasks or by a different assessor or panelNOTE Reproducibility may be measured as any of the f
28、ollowing: the reproducibility of a panel in the short term, measured between two or more sessions separated by several days; the reproducibility of a panel in the medium or long term, measured among sessions separated by several months; the reproducibility between different panels, in the same labor
29、atory or in different laboratories; the reproducibility of assessments by a single assessor of different attributes of a product.3.9validationprocess of establishing that sensory data correlate with other data on samples of the same product (e.g. laboratory measurements, consumer perception, results
30、 from other panels, consumer complaints) or that a panel or assessor is able to meet specified performance criteria3.10sessionoccasion on which products are assessedNOTE In a single session either one or several products may be assessed by one or several assessors. For an assessor, whether alone or
31、as part of a panel, sessions are separated in time.3.11replicate sessionssessions in which the assessors, the products, the test conditions, and the task are the same4 PrincipleThis International Standard is concerned with sensory panels used to assess the magnitude of one or more sensory attributes
32、 in order to make quantitative descriptions or profiles of products. Different methods are appropriate to the assessment and monitoring of the performance of panels used for difference testing.2 ISO 2012 All rights reservedBS ISO 11132:2012ISO 11132:2012(E)The performance of a quantitative sensory p
33、anel may be evaluated by using assessments already available or from panel sessions conducted specifically for the purpose of obtaining performance data.This International Standard may be used either for periodic monitoring or for reviewing ongoing profile data.A dedicated monitoring procedure at pe
34、riodic intervals is appropriate for accreditation and other purposes. Figure 1 is a flow chart for this procedure.To review ongoing profile data generated by a panel, it can be appropriate to use data that originated from quite different profiling experiments using different product types, product n
35、umbers, etc. The procedure is the same as that shown in Figure 1. However, as there are no predefined differences, it is recommended that attributes that are significantly discriminated by the panel as a whole for a given profile be used as the key measures to check the performance of individual pan
36、elists. Attributes that result in no significant difference cannot be reliably used to check consistency since the lack of agreement within and between panelists probably means that the products are very similar for those characteristics.a) Monitoring by means of performance validation. Use a small
37、set of samples (perhaps three or four) for which some attributes are known to be different. These attributes are then used as the key measures on which to measure performance. b) Overall panel performance 1) How many of the expected key attributes have been significantly discriminated? 2) How many o
38、f the key attributes show an interaction of sample and assessor? This gives an initial indication of where there is least consistency across the panel (7.3.2) 3) Repeatability of the panel for the key attributes in replicate sessions (7.3.3)? c) Individual assessor performance 1) Discrimination abil
39、ity: how many of the expected key attributes have been significantly discriminated? 2) Repeatability: consistency of discrimination for a given attribute and product (7.4.2)? 3) Contributions to interaction: for which attributes do interactions occur? i) Interaction due to cross-over effects (7.4.4)
40、 ii) Interaction due to different use of the scale (7.4.5) d) Where performance issues have been identified, either for the panel or for individual assessors, appropriate training sessions should be planned. Figure 1 Flow chart for performance monitoringIn a single session, the following indicators
41、can be determined. Bias of an assessor, measured as the difference between the assessors mean and a known, true value, or the mean of the panel as an estimate of the true value. Repeatability of an assessor, inversely related to the standard deviation (SD) of repeat assessments by the assessor of th
42、e same sample, or between replicates of the same product. Reproducibility of an assessor, inversely related to the SD of the assessors biases across individual products. ISO 2012 All rights reserved 3BS ISO 11132:2012ISO 11132:2012(E) Discrimination of an assessor, measured as the ability to assign
43、consistently different scores to different products.Bias in an assessor may indicate sensory sensitivity that is different from other assessors and/or use of the response scale in a way that differs from other assessors.If an assessor appears to give assessments that differ from those of other asses
44、sors, review all the results with a view to determining whether:a) the assessments are consistent or variable for repeated samples of the same product;b) the assessments are similar or different for samples of different products;c) bias occurs with all, or only some, assessment scales.Analysis of va
45、riance (ANOVA) can be used to investigate these questions.In some cases, bias may indicate an assessor of superior ability whose results are particularly useful. In other cases, an assessor showing bias may require retraining or removal from the panel.A single, consistent approach to statistical ana
46、lysis of the results is described here. However, some attributes of panel performance can be assessed by more than one descriptive measure. For instance, error mean square and error SD (its square root) both express variability in the evaluation of a product. The measures used should be those that a
47、re usual in the field of application.Other relevant measures of agreement between assessors in the use of the scale for an attribute are the interaction of assessor and product and the coefficient of correlation between an assessors scores and the panel means. An assessor may have no bias, but may b
48、e using the scale in a different way. A correlation close to 1, a regression slope close to 1, and a regression intercept close to 0 indicate good agreement between an assessor and the rest of the panel.With a small number of assessments (fewer than six) the correlation coefficient should be interpr
49、eted with caution, as it can be high (up to 0,7), by chance alone.5 Experimental conditionsThe test facilities shall be in accordance with ISO 8589.6 Qualification of assessorsThe panel shall have the level of qualification and experience of selected assessors (ISO 8586) or better.7 Procedure7.1 Monitoring via formal performance validationAt each session, the panel of assessors should be presented with a set of samples similar to those the panel are to assess when evaluating products and for which st
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