ISO/TC 34/SC 12 - Sensory analysis

This document gives guidelines for assessing the overall performance of a quantitative descriptive panel and the performance of each panel member. This document is applicable to the validation of the training of individual assessors or panels, as well as to the performance monitoring of established panels. This document does not apply to the panel performance for descriptive methods where the individual scores of each assessor are not recorded, where there is no single list of attributes that is common to all the assessors, or where dominance rather than intensity is measured. Consequently, the performance of descriptive panels using methods such as consensus profile, free-choice profile, flash profile and temporal dominance of sensations (TDS) are out of scope. The methods specified in this document are for monitoring and assessing the ability of a panel and its assessors to discriminate between products, the agreement between assessors of the same panel and the repeatability of these assessors in their intensity scoring. Reproducibility, including both the comparison between panels and the comparison within the same panel of several evaluations conducted under different conditions (i.e. separated in time), is out of scope of this document. The methods specified in this document can be used, in full or a selection only, by the panel leader to appraise continuously the performance of panels or individual assessors. The methods listed are not exhaustive and other appropriate methods can also be used.

This document specifies a method for applying magnitude estimation to the evaluation of sensory attributes. The methodology specified covers the training of assessors, and obtaining magnitude estimations as well as their statistical interpretation.

This document gives guidelines for substantiating sensory claims on food and non-food products and their packaging for advertising consumer-packaged goods. This document differentiates sensory claims from other types of claims. It provides classification and examples of the different types of sensory claims. It highlights special issues associated with testing to substantiate sensory claims. It includes case studies and references. This document does not apply to: — specific or detailed requirements for different test methods that are used to support sensory claims; — factual claims regarding a product's country of origin, ingredients, processing and nutritional components; — factual claims regarding the technical features of the product; — claims regarding a product's health, medical or therapeutic benefits, physiological effects, structure or function benefits when consumed or applied to the human body; — claims based on instrumental assessments of the attributes or performance of a product (i.e. instrumental assessments; in this case, test methods are used in which no human participant evaluates the product and/or no human participant provides a response to a product); — claims about services (e.g. a house cleaning service, airline services, automobile services); — claims about large/slow moving consumer goods (autos, refrigerators, stoves, etc.).

This document specifies a procedure for determining whether a perceptible sensory difference or similarity exists between samples of two products. The method is a forced-choice procedure. The method is applicable whether a difference exists in a single sensory attribute or in several attributes. The method is statistically more efficient than the duo-trio test (described in ISO 10399), but has limited use with products that exhibit strong carryover and/or lingering flavours. The method is applicable even when the nature of the difference is unknown [i.e. it determines neither the size nor the direction of difference between samples, nor is there any indication of the attribute(s) responsible for the difference]. The method is applicable only if the products are homogeneous. The method is effective for: a) determining that: either a perceptible difference results (triangle testing for difference); a perceptible difference does not result (triangle testing for similarity), when, for example, a change is made in ingredients, processing, packaging, handling or storage; b) selecting, training and monitoring assessors.

This document specifies a method for developing a texture profile of food products (solids, semi-solids, liquids) or non-food products (e.g. cosmetics). This method is one approach to sensory texture profile analysis and other methods exist. This method describes various steps in the process of establishing a complete description of the textural attributes of a product. This method is applicable to: — screening and training assessors; — orientating assessors through the development of definitions and evaluation techniques for textural characteristics; — characterizing the textural attributes of a product in order to establish its standard profile and to discern any later changes; — improving old products and developing new products; — studying various factors that can affect the textural attributes of a product, e.g. changes in process, time, temperature, ingredients, packaging or shelf-life, and storage conditions; — comparing a product with another similar product to determine the nature and intensity of textural differences; — correlating sensory and instrumental and/or physical measurements.

This document specifies a procedure for statistically analysing data from forced-choice sensory discrimination tests, such as the triangle, duo-trio, 3-AFC, 2-AFC, in which after every trial of the discrimination test the decision can be made to stop testing and declare a difference, to stop testing and declare no difference, or to continue testing. The sequential method often allows for a decision to be made after fewer trials of the discrimination test than would be required by conventional approaches that use predetermined numbers of assessments. The method is effective for: a) determining that either: a perceptible difference results; or a perceptible difference does not result when, for example, a change is made in ingredients, processing, packaging, handling or storage; b) selecting, training and monitoring assessors. N

This document gives guidelines for the implementation of a sensory analysis programme in quality control (QC), including general elements and procedures. It is applicable to food and non-food industries. It is limited to in-plant sensory analysis in QC.

ISO 13301:2018 gives guidelines for - obtaining data on the detection of stimuli that evoke responses to odour, flavour and taste by a 3-AFC (three-alternative forced-choice) procedure, and - the processing of the data to estimate the value of a threshold and its error bounds, and other statistics related to the detection of the stimulus. Typically, the procedures will be used in one of the following two modes: - investigation of the sensitivity of assessors to specific stimuli; - investigation of the ability of a chemical substance to stimulate the chemoreceptive senses. (Although experiments can encompass both modes.) Examples of the first mode include studies of the differences among individuals or specified populations of individuals in sensitivities and of the effects of age, gender, physiological condition, disease, administration of drugs and ambient conditions on sensitivity. Examples of the latter mode include - studies in flavour chemistry and the impact of specified chemicals on the flavour of foods, - classification of chemicals for their impact on humans, if present in the environment, - studies on the relationship of molecular structure to capacity of a chemical to act as a stimulant, - quality assurance of gaseous effluents and of water, foods and beverages, and - studies in the mechanism of olfaction. In both modes, the way in which probability of a correct response changes with intensity of stimulus, i.e. the slope of the dose/response curve, could be an important aspect of the study as well as the threshold value, and the data processing procedures described here provide this information. The focus of ISO 13301:2018 is on data requirements and on computational procedures. Regarding the validity of the data, the text is restricted to general rules and precautions. It does not differentiate between detection and difference thresholds; fundamentally, the procedures measure a difference threshold because a test sample is compared with a reference sample. Typically, the reference sample is not intended to contain the stimulus under investigation, but the guidelines do not exclude experimental design in which the reference could contain the stimulus, or it might not be known if the reference contains the stimulus. The guidelines do not measure a recognition threshold as defined in ISO 5492. They do not address the standardization of methods of determining air quality as discussed in EN 13725.

ISO 10399:2017 specifies a procedure for determining whether a perceptible sensory difference or similarity exists between samples of two products. The method is a forced-choice procedure. The method is applicable whether a difference exists in a single sensory attribute or in several attributes. The method is statistically less efficient than the triangle test (described in ISO 4120) but is easier to perform by the assessors. The method is applicable even when the nature of the difference is unknown (i.e. it determines neither the size nor the direction of difference between samples, nor is there any indication of the attribute(s) responsible for the difference). The method is applicable only if the products are fairly homogeneous. The method is effective for a) determining that either a perceptible difference results (duo-trio testing for difference), or a perceptible difference does not result (duo-trio testing for similarity) when, for example, a change is made in ingredients, processing, packaging, handling or storage, and b) for selecting, training and monitoring assessors. Two forms of the method are described: - the constant-reference technique, used when one product is familiar to the assessors (e.g. a sample from regular production); - the balanced-reference technique, used when one product is not more familiar than the other.

ISO 8588:2017 specifies a procedure for determining whether a perceptible sensory difference exists between samples of two products. The method applies whether a difference exists in a single sensory attribute or in several. The "A" ? "not A" test can be used in sensory analysis in the following ways: a) as a difference test, particularly for evaluating samples having variations, for example, in appearance (making it difficult to obtain strictly identical repeat samples) or in aftertaste (making direct comparison difficult); b) as a recognition test, particularly for determining whether an assessor or group of assessors identifies a new stimulus in relation to a known stimulus (for example, recognition of the quality of the sweet taste of a new sweetener); c) as a perception test, to determine the ability of an assessor to discriminate stimuli. The "A" ? "not A" test is not appropriate for assessing if two products are sufficiently similar to be used interchangeably (i.e. for similarity testing) because the "A" ? "not A" test inherently involves replicate evaluations of the same products by all assessors. These replicate evaluations violate the basic assumptions for similarity tests to be statistically valid. Examples of its application are given in Annex B. NOTE Bi and Ennis[1] point out that the estimate of the discriminal distance, d', between the "A" and "not A" samples is the same regardless of the nature of the replicated evaluations performed in the test but that the estimate of the variance of d' does depend on how the replicate evaluations were performed. As such, no general discussion of a Thurstonian analysis of the "A" ? "not A" method, nor of the power of the test is undertaken in this document. Interested readers are referred to Reference [1] for a detailed discussion of the topic.

ISO 6658:2017 gives general guidance on the use of sensory analysis. It describes tests for the examination of foods and other products by sensory analysis, and includes some general information on the techniques to be used if statistical analysis of the results is required. Generally these tests are intended only for objective sensory analysis. However, if a test can be used for determining preference in hedonic test, this is indicated. A hedonic test aims to determine the acceptability of the products and/or to determine preferences among two or more products by the specified consumer population. The methods are effective for determining whether a perceptible preference exists (difference in degree of liking), or whether no perceptible preference exists (paired similarity test). General guidance for hedonic tests is given in ISO 11136.

ISO 13299:2016 gives guidelines for the overall process for establishing a sensory profile. Sensory profiles can be established for all products or samples which can be evaluated by the senses of sight, odour, taste, touch, or hearing (e.g. food, beverage, tobacco product, cosmetic, textile, paper, packaging, sample of air or water). This International Standard can also be useful in studies of human cognition and behaviour. Some applications of sensory profiling are as follows: - to develop or change a product; - to define a product, production standard, or trading standard in terms of its sensory attributes; - to define a reference "fresh" product for shelf-life testing; - to study and improve shelf-life of a product; - to compare a product with a reference product or with other similar products on the market or under development; - to map a product's perceived attributes for the purpose of relating them to factors such as instrumental, chemical or physical properties, and/or to consumer acceptability; - to characterize by type and intensity the off-odours or off-tastes in a sample (e.g. in pollution studies).

ISO 16779:2015 specifies methods for the determination and verification of the shelf life of foodstuffs by means of sensory tests. Sensory characteristics to be evaluated are changes in appearance, odour, flavour, taste, trigeminal sensation, and texture during assumed preservation periods. It is intended to support the development of individual approaches. ISO 16779:2015 does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this International Standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. NOTE For the purposes of calculating the shelf life, before microbiological, chemical and physical investigation results are used in addition to sensory testing.

ISO 11136:2014 describes approaches for measuring, within a controlled area, the degree to which consumers like or relatively like products. It uses tests based on collecting consumers' responses to questions, generally on paper or via a keyboard or a touch screen. Tests of a behavioural nature (such as recording quantities consumed ad libitum by the consumers) do not fall within the scope of ISO 11136:2014.

ISO 8586:2012 specifies criteria for the selection and procedures for the training and monitoring of selected assessors and expert sensory assessors. It supplements the information given in ISO 6658.

This International Standard specifies a set of objective tests for familiarizing assessors with sensory analysis. The test methods specified can be useful to:
a) teach assessors to recognize tastes and to distinguish between them (see Clause 8);
b) teach assessors to know and to familiarize different types of threshold tests (see Clause 9);
c) make assessors aware of their own sensitivity of taste;
d) enable test supervisors to carry out a preliminary categorization of assessors.
The methods can also be used as a periodic monitor of the sensitivity of taste of assessors who are already members of sensory analysis panels.

This International Standard specifies a set of objective tests for familiarizing assessors with sensory analysis. The test methods specified can be useful to:
a) teach assessors to recognize tastes and to distinguish between them (see Clause 8);
b) teach assessors to know and to familiarize different types of threshold tests (see Clause 9);
c) make assessors aware of their own sensitivity of taste;
d) enable test supervisors to carry out a preliminary categorization of assessors.
The methods can also be used as a periodic monitor of the sensitivity of taste of assessors who are already members of sensory analysis panels.

ISO 11037:2011 establishes guidelines for the sensory evaluation of the colours of products. The procedures specified are applicable to solid, semi-solid, powder and liquid products, which can be opaque, translucent, cloudy or transparent in nature, as well as matt or glossy. General information is also given about the viewing and lighting conditions to be used in various situations in sensory analysis, such as difference testing, profile analysis and grading methods, performed by panels of selected assessors or by individual experts in special situations. ISO 11037:2011 does not deal with consumer testing or with assessment of the metamerism of colours of food products.

ISO 29842:2011 specifies a method for the application of balanced incomplete block designs to sensory descriptive and hedonic tests. ISO 29842:2011 applies when the number of test samples exceeds the number of evaluations that an assessor can perform reliably in a single session. ISO 29842:2011 also specifies the fundamental characteristics of balanced incomplete block designs and establishes guidelines for their application in sensory evaluation.

ISO 8589:2007 provides general guidance for the design of test rooms intended for the sensory analysis of products. It describes the requirements to set up a test room comprising a testing area, a preparation area, and an office, specifying those that are essential or those that are merely desirable. ISO 8589:2007 is not specific for any product or test type. Although many of the general principles are similar, ISO 8589:2007 does not address test facilities for the specialized examination of products in inspection or in-plant quality-control applications.

ISO 8587:2006 describes a method for sensory evaluation with the aim of placing a series of test samples in rank order. This method allows for assessing differences among several samples based on the intensity of a single attribute, of several attributes or of an overall impression. It is used to find if differences exist, but cannot determine the degree of difference that exists between samples. ISO 8587:2006 is suited for the following cases: a) evaluation of assessors' performance (training assessors, determining perception thresholds of individuals or groups); b) product assessment (pre-sorting of samples, determination of the influence on intensity levels of one or more parameters and determination of the order of preference in a global hedonic test).

ISO 5496:2006 describes several types of method for determining the aptitude of assessors and for training assessors to identify and describe odoriferous products. The methods described in ISO 5496:2006 are suitable for use by the agri-foodstuffs industries employing olfactory analysis (e.g. perfumery, cosmetics and aromatics).

ISO 13300-2:2006 gives guidelines for the recruitment and training of panel leaders. In addition, it describes the principal activities and responsibilities of a panel leader for sensory analysis.

ISO 13300-1:2006 provides guidance on staff functions in order to improve the organization of a sensory evaluation laboratory, to optimize the use of personnel, and to improve the efficiency of sensory tests. It is applicable to any organization planning to establish a formal structure for sensory evaluation. The main aspects to be considered are the education, background and professional competence of staff members, and the responsibilities of staff members at three different functional levels: sensory manager; sensory analyst or panel leader; panel technician. These guidelines are valid for all different types of sensory evaluation laboratories, in particular those in industry, in research and development organizations, in service organizations and in the field of official authorities concerned with product control. In principle, it can be assumed that the sensory evaluation laboratory can perform all types of sensory tests. This means analytical tests such as discrimination tests, descriptive analysis (sensory profile), as well as consumer tests (e.g. hedonic tests). The individual profile of sensory activities of an organization determines the boundaries and conditions to be considered for planning and implementing the sensory evaluation laboratory and its staff. The application of this guidance by the organization is flexible and depends on the needs and possibilities within an organization. For example, personnel might not be available for three levels of staff function and, thus, the duties can be divided among staff accordingly. Also, in a staff of two persons the technical/scientific functions can be shared between a person handling the administrative/management functions and the individual handling the operational functions.

ISO 16657:2006 specifies the characteristics of a glass intended for use in the sensory analysis of the organoleptic attributes of odour, taste and flavour of virgin olive oils, for the classification of such oils. The glass is not intended for the analysis of the colour or texture of olive oils. In addition, it describes an adapted heating unit used to reach and maintain the right temperature for this analysis.

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).

ISO 4121:2003 provides guidelines describing quantitative response scales (where the response obtained indicates the intensity of perception) and their use when assessing samples. It is applicable to all quantitative assessment, whether global or specific and whether objective or hedonic. It is intentionally limited to the most commonly used measurement scales for sensory assessment.

ISO 13302:2003 describes methods for assessing the changes caused by packaging to the sensory attributes of foodstuffs or their simulants. The methodology can be used as initial selection to assess a suitable packaging material or as subsequent acceptability screening of individual batches/production run. ISO 13302:2003 is applicable to all materials usable for packaging foodstuffs (e.g. paper, cardboard, plastic, foils, wood). Moreover, the scope can be extended to any objects intended to come into contact with foodstuffs (e.g. kitchen utensils, coatings, leaflets, or parts of equipment such as seals or piping) with the aim of controlling food compatibility from a sensory point of view according to the legislation in force.

Describes a method for identifying and selecting descriptors which can then be used for drawing up the sensory profile of a product. Describes the different stages in the process for setting up test through which a complete description of the sensory attributes of a product can be obtained: from a qualitative point of view by defining by means of descriptors all the perceptions for distinguishing one product from others of the same type; from a quantitative point of view, by evaluating the intensity of each descriptor. This method can be used to define a production standard; to improve or develop products; to study the influence of the ageing of products and also of the conditions of storage and preservation; to compare a product with those of the same type already on the market.

Application, in particular, to samples of intensely flavoured products and to samples of very concentrated products. The principle consists in making a preperation which allows direct assessment of the organoleptic properties of a sample according to the analysis required, as follows: a) for assessment of the properties of the sample itself: mixing the sample with a chemically defined substance or addition to a food medium considered to be neutral; b) for assesment of the effects of the sample in a food preperation: adding the sample to the food preparation for which it is intended.

The tasting glass consists of a cup (an "elongated egg") supported by a stem resting on a base. The opening of the cup is narrower than the convex part so as to concentrate the bouquet. Further are given physical, dimensional and special characteristics. An annex comprises recommendations for use.

ISO 11132:2012 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 measure 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 similar 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 to 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 retraining needs or to identify assessors who are not performing well enough to continue participating. The methods specified in ISO 11132:2012 can be used by the panel leader to appraise continuously the performance of panels or individual assessors. ISO 11132:2012 applies to individuals or panels in training as well as for established panels.

ISO 8586-2:2008 specifies criteria for choosing people with particular sensory skills from selected assessors or from product, process or marketing specialists who themselves satisfy the selection criteria specified in ISO 8586-1. It specifies principles and procedures for choosing them and expanding their knowledge and abilities to the levels required of expert sensory assessors. ISO 8586-2:2008 sets out requirements for expert sensory assessors to establish sensory profiles of products and materials through the use of descriptors. Specific knowledge of products or materials by expert sensory assessors is not necessary to fulfil these requirements. ISO 8586-2:2008 supplements the information given in ISO 6658.

ISO 6658:2005 gives general guidance on the use of sensory analysis. It describes tests for the examination of foods by sensory analysis, and includes some information on the techniques to be used if statistical analysis of the results is required. Generally these tests are intended only for objective sensory analysis. However, if a test can be used for determining preference, this is indicated.

ISO 16820:2004 describes a procedure for statistically analysing data from forced-choice sensory discrimination tests, such as the Triangle, Duo-Trio, 3-AFC, 2-AFC, in which after every trial of the discrimination test the decision can be made to stop testing and declare a difference, to stop testing and declare no difference, or to continue testing. The sequential method often allows for a decision to be made after fewer trials of the discrimination test than would be required by conventional approaches that use predetermined numbers of assessments. The method is effective for a) determining that either a perceptible difference results, or a perceptible difference does not result when, for example, a change is made in ingredients, processing, packaging, handling or storage; or b) for selecting, training and monitoring assessors.

ISO 4120:2004 describes a procedure for determining whether a perceptible sensory difference or similarity exists between samples of two products. The method is a forced-choice procedure. The method applies whether a difference can exist in a single sensory attribute or in several attributes. The method is statistically more efficient than the duo-trio test, but has limited use with products that exhibit strong carryover and/or lingering flavours. The method is applicable even when the nature of the difference is unknown (i.e. it determines neither the size nor the direction of difference between samples, nor is there any indication of the attributes responsible for the difference). The method is applicable only if the products are fairly homogeneous. The method is effective for a) determining that either a perceptible difference results (triangle testing for difference), or a perceptible difference does not result (triangle testing for similarity) when, for example, a change is made in ingredients, processing, packaging, handling or storage; b) or for selecting, training and monitoring assessors.

ISO 10399:2004 describes a procedure for determining whether a perceptible sensory difference or similarity exists between samples of two products. The method is a forced-choice procedure. The method is applicable whether a difference exists in a single sensory attribute or in several attributes. The method is statistically less efficient than the triangle test but is easier to perform by the assessors. The method is applicable even when the nature of the difference is unknown (i.e. it determines neither the size nor the direction of difference between samples, nor is there any indication of the attributes responsible for the difference). The method is applicable only if the products are fairly homogeneous. The method is effective for a) determining that either a perceptible difference results (duo-trio testing for difference), or a perceptible difference does not result (duo-trio testing for similarity) when, for example, a change is made in ingredients, processing, packaging, handling or storage; or b) for selecting, training and monitoring assessors. Two forms of the method are described: the constant-reference technique, used when one product is familiar to the assessors (e.g. a sample from regular production), and the balanced-reference technique, used when one product is not more familiar than the other.

ISO 13299:2003 describes the overall process for developing a sensory profile. Sensory profiles can be established for products such as foods and beverages, and can also be useful in studies of human cognition and behaviour. Some applications of sensory profiling are: to develop or change a product; to define a product, production standard or trading standard in terms of its sensory attributes; to study and improve shelf-life; to define a reference fresh product for shelf-life testing; to compare a product with a standard or with other similar products on the market or under development; to map a product's perceived attributes for the purpose of relating them to factors such as instrumental, chemical or physical properties, and/or to consumer acceptability; to characterize by type and intensity the off-odours or off-tastes in a sample of air or water (e.g. in pollution studies).

ISO 13301 provides guidance on: obtaining data on the detection of chemical stimuli that evoke responses to odour, flavour and taste by a 3-AFC (three alternative forced choice) procedure; the processing of the data to estimate the value of a threshold and its error bounds, and other statistics related to the detection of the stimulus. Typically the procedures will be used in one of the following two modes: investigation of the sensitivity of assessors to specific stimuli; investigation of the ability of a chemical substance to stimulate the chemoreceptive senses. (Although experiments may encompass both modes.) Examples of the first mode include studies of the differences among individuals or specified populations of individuals in sensitivities and of the effects of age, gender, physiological condition, disease, administration of drugs, and ambient conditions on sensitivity. Examples of the latter mode include: studies in flavour chemistry and the impact of specified chemicals on the flavour of foods; classification of chemicals, if present in the environment, for their impact on humans; studies on the relationship of molecular structure to capacity of a chemical to act as a stimulant; quality assurance of gaseous effluents and of water, foods and beverages; studies in the mechanism of olfaction.

Describes a method of developing a texture profile of food products or non-food products. This method is just one approach to sensory texture profile analysis. Other methods exist. It describes various steps in the process of establishing a complete description of the textural attributes of a product.