ASTM E679-04

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:E679–04
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. 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. 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.
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 panelist’s threshold is centered within the range of
concentrationsheorshereceives.Theuseralsoneedstokeepinmindtheverylargedegreeofrandom
errorassociatedwithestimatingtheprobabilityofdetectionfromonly50to1003-AFCpresentations.
1. Scope 1.6 Physical methods of sample presentation for threshold
determinationarenotapartofthispractice,andwilldependon
1.1 This practice describes a rapid test for determining
the physical state, size, shape, availability, and other properties
sensory thresholds of any substance in any medium.
of the samples.
1.2 Itprescribesanoveralldesignofsamplepreparationand
1.7 It is recognized that the degree of training received by a
a procedure for calculating the results.
panel with a particular substance may have a profound influ-
1.3 The threshold may be characterized as being either (a)
2
ence on the threshold obtained with that substance (1).
only detection (awareness) that a very small amount of added
1.8 Thresholds determined by using one physical method of
substance is present but not necessarily recognizable, or (b)
presentation are not necessarily equivalent to values obtained
recognition of the nature of the added substance.
by another method.
1.4 The medium may be a gas, such as air, a liquid, such as
waterorsomebeverage,orasolidformofmatter.Themedium
2. Referenced Documents
may be odorless or tasteless, or may exhibit a characteristic
3
2.1 ASTM Standards:
odor or taste per se.
D1292 Test Method for Odor in Water
1.5 This practice describes the use of a multiple forced-
E544 Practices for Referencing Suprathreshold Odor Inten-
choice sample presentation method in an ascending concentra-
sity
tion series, similar to the method of limits.
E1432 Practice for Defining and Calculating Individual and
1 2
This practice is under the jurisdiction of ASTM Committee E18 on Sensory The boldface numbers in parentheses refer to the list of references at the end of
Evaluation of Materials and Products and is the direct responsibility of Subcom- this practice.
3
mittee E18.04 on Fundamentals of Sensory. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved April 1, 2004. Published April 2004. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1979. Last previous edition approved in 1997 as E679 – 91 (1997). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/E0679-04. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

---------------------- Page: 1 ----------------------
E679–04
Group Sensory Thresholds from Forced-Choice Data Sets of interest.This concentration scale should increase in geomet-
of Intermediate Size ric increments so that any two adjacent concentration steps are
4
2.2 CEN Standards: separated by a
...