ASTM E 679 : 2019

1.1This practice describes a rapid test for determining sensory thresholds of any substance in any medium.

1.2It prescribes an overall design of sample preparation and a procedure for calculating the results.

1.3The 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.

1.4The 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.

1.5This practice describes the use of a multiple forced-choice sample presentation method in an ascending concentration series, similar to the method of limits.

1.6Physical 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.

1.7It 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

1.8Thresholds determined by using one physical method of presentation are not necessarily equivalent to values obtained by another method.

1.9This 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.