ASTM E679-19

Standard Practice for Determination of Odor and Taste Thresholds By a Forced-Choice Ascending Concentration Series Method of Limits

SIGNIFICANCE AND USE
5.1 Sensory thresholds are used to determine the potential of substances at low concentrations to impart odor, taste, skinfeel, etc. to some form of matter.  
5.2 Thresholds are used, for example, in setting limits for air pollution, in noise abatement, in water treatment, and in food systems.  
5.3 Thresholds are used to characterize and compare the sensitivity of individual or groups to given stimuli, for example, in medicine, in ethnic studies, and in the study of animal species.
SCOPE
1.1 This practice describes a rapid test for determining sensory thresholds of any substance in any medium.  
1.2 It prescribes an overall design of sample preparation and a procedure for calculating the results.  
1.3 The threshold may be characterized as being either (a) only detection  (awareness) that a very small amount of added substance is present but not necessarily recognizable, or (b) recognition  of the nature of the added substance.  
1.4 The medium may be a gas, such as air, a liquid, such as water or some beverage, or a solid form of matter. The medium may be odorless or tasteless, or may exhibit a characteristic odor or taste per se.  
1.5 This practice describes the use of a multiple forced-choice sample presentation method in an ascending concentration series, similar to the method of limits.  
1.6 Physical methods of sample presentation for threshold determination are not a part of this practice, and will depend on the physical state, size, shape, availability, and other properties of the samples.  
1.7 It is recognized that the degree of training received by a panel of assessors with a particular substance may have a profound influence on the threshold obtained with that substance  (1).2  
1.8 Thresholds determined by using one physical method of presentation are not necessarily equivalent to values obtained by another method.  
1.9 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 14-Aug-2019
• ICS: 67.240 - Sensory analysis
• Technical Committee: E18 - Sensory Evaluation
• Drafting Committee: E18.04 - Fundamentals of Sensory

Relations

• Referred By: ASTM E1432-19 - Standard Practice for Defining and Calculating Individual and Group Sensory Thresholds from Forced-Choice Data Sets of<brk/> Intermediate Size
• Effective Date: 15-Aug-2019

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E679 − 19
Standard Practice for
Determination of Odor and Taste Thresholds By a Forced-
1
Choice Ascending Concentration Series Method of Limits
This standard is issued under the fixed designation E679; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
The obtaining of odor and taste thresholds requires the sensory responses of a selected group of
individualscalledassessors.Thesethresholdsmaybedeterminedinordertonotetheeffectofvarious
added substances on the odor and taste of a medium. They may also be determined in order to
characterize and compare the odor or taste sensitivity of individuals or groups.
It is recognized that precise threshold values for a given substance do not exist in the same sense
that values of vapor pressure exist. The ability to detect a substance by odor or taste is influenced by
physiological factors and criteria used in producing a response by the assessor. The parameters of
sample presentation introduce further variations.Thus, the flowrate of a gaseous, odorous sample has
an influence on the detectability of an odor. However, a concentration range exists below which the
odorortasteofasubstancewillnotbedetectableunderanypracticalcircumstances,andabovewhich
individuals with a normal sense of smell or taste would readily detect the presence of the substance.
Thethresholddeterminedbythispracticeisnottheconventionalgroupthreshold(thestimuluslevel
detectable with a probability of 0.5 by 50% of the population) as obtained by Practice E1432, but
rather a best estimate not far therefrom. The bias of the estimate depends on the concentration scale
steps chosen and on the degree to which each assessor’s threshold is centered within the range of
concentrationstheyreceive.Theuseralsoneedstokeepinmindtheverylargedegreeofrandomerror
associated with estimating the probability of detection from only 50 to 100 3-AFC presentations.
1. Scope 1.5 This practice describes the use of a multiple forced-
choice sample presentation method in an ascending concentra-
1.1 This practice describes a rapid test for determining
tion series, similar to the method of limits.
sensory thresholds of any substance in any medium.
1.6 Physical methods of sample presentation for threshold
1.2 Itprescribesanoveralldesignofsamplepreparationand
determinationarenotapartofthispractice,andwilldependon
a procedure for calculating the results.
thephysicalstate,size,shape,availability,andotherproperties
of the samples.
1.3 The threshold may be characterized as being either (a)
only detection (awareness) that a very small amount of added
1.7 It is recognized that the degree of training received by a
substance is present but not necessarily recognizable, or (b)
panel of assessors with a particular substance may have a
recognition of the nature of the added substance. profound influence on the threshold obtained with that sub-
2
stance (1).
1.4 The medium may be a gas, such as air, a liquid, such as
1.8 Thresholdsdeterminedbyusingonephysicalmethodof
waterorsomebeverage,orasolidformofmatter.Themedium
presentation are not necessarily equivalent to values obtained
may be odorless or tasteless, or may exhibit a characteristic
by another method.
odor or taste per se.
1.9 This international standard was developed in accor-
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
1
This practice is under the jurisdiction of ASTM Committee E18 on Sensory
Evaluation and is the direct responsibility of Subcommittee E18.04 on Fundamen-
tals of Sensory.
Current edition approved Aug. 15, 2019. Published September 2019. Originally
2
approved in 1979. Last previous edition approved in 2011 as E679–04(2011). Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof
DOI: 10.1520/E0679-19. this practice.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E679 − 19
Development of International Standards, Guides and Recom- 3.1.10 geometric mean—the nth root of the product of
mendations issued by the World Trade Organization Technical terms. In this method, the terms are concentration values.
Barriers to Trade (TBT) Committee.
4. Summary of Practice
2. Referenced Documents
4.1 A series of test samples is prepared by dispersing the
3
2.1 ASTM Standards:
substance whose threshold
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E679 − 04 (Reapproved 2011) E679 − 19
Standard Practice for
Determination of Odor and Taste Thresholds By a Forced-
1
Choice Ascending Concentration Series Method of Limits
This standard is issued under the fixed designation E679; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
The obtaining of odor and taste thresholds requires the sensory responses of a selected group of
individuals called panelists.assessors. These thresholds may be determined in order to note the effect
of various added substances on the odor and taste of a medium. They may also be determined in order
to characterize and compare the odor or taste sensitivity of individuals or groups.
It is recognized that precise threshold values for a given substance do not exist in the same sense
that values of vapor pressure exist. The ability to detect a substance by odor or taste is influenced by
physiological factors and criteria used in producing a response by the panelist.assessor. The
parameters of sample presentation introduce further variations. Thus, the flowrate of a gaseous,
odorous sample has an influence on the detectability of an odor. However, a concentration range exists
below which the odor or taste of a substance will not be detectable under any practical circumstances,
and above which individuals with a normal sense of smell or taste would readily detect the presence
of the substance.
The threshold determined by this practice is not the conventional group threshold (the stimulus level
detectable with a probability of 0.5 by 50 % of the population) as obtained by Practice E1432, but
rather a best estimate not far therefrom. The bias of the estimate depends on the concentration scale
steps chosen and on the degree to which each panelist’sassessor’s threshold is centered within the
range of concentrations he or she receives. they receive. The user also needs to keep in mind the very
large degree of random error associated with estimating the probability of detection from only 50 to
100 3-AFC presentations.
1. Scope
1.1 This practice describes a rapid test for determining sensory thresholds of any substance in any medium.
1.2 It prescribes an overall design of sample preparation and a procedure for calculating the results.
1.3 The threshold may be characterized as being either (a) only detection (awareness) that a very small amount of added
substance is present but not necessarily recognizable, or (b) recognition of the nature of the added substance.
1.4 The medium may be a gas, such as air, a liquid, such as water or some beverage, or a solid form of matter. The medium
may be odorless or tasteless, or may exhibit a characteristic odor or taste per se.
1.5 This practice describes the use of a multiple forced-choice sample presentation method in an ascending concentration series,
similar to the method of limits.
1.6 Physical methods of sample presentation for threshold determination are not a part of this practice, and will depend on the
physical state, size, shape, availability, and other properties of the samples.
1.7 It is recognized that the degree of training received by a panel of assessors with a particular substance may have a profound
2
influence on the threshold obtained with that substance (1).
1
This practice is under the jurisdiction of ASTM Committee E18 on Sensory Evaluation and is the direct responsibility of Subcommittee E18.04 on Fundamentals of
Sensory.
Current edition approved Aug. 1, 2011Aug. 15, 2019. Published August 2011September 2019. Originally approved in 1979. Last previous edition approved in 20042011
as E679 – 04.E679 – 04 (2011). DOI: 10.1520/E0679-04R11.10.1520/E0679-19.
2
The boldface numbers in parentheses refer to the list of references at the end of this practice.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E679 − 19
1.8 Thresholds determined by using one physical method of presentation are not necessarily equivalent to values obtained by
another method.
1.9 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guide
...