ISO 4120:2021 pdf download – Sensory analysis — Methodology — Triangle test.
5.3 Prepare the samples out of sight of the assessors and in an identical manner (e.g. same apparatus, same vessels, same quantities of product). 5.4 Assessors shall not be able to identify the samples from the way in which they are presented. For example, in a taste test, avoid any differences in appearance. Mask any irrelevant colour differences using light filters and/or subdued illumination. 5.5 Code the test samples in a uniform manner, preferably using three-digit numbers, chosen at random for each test. Each triad is composed of three samples, each with a different code. Preferably, different codes should be used for each assessor during a session. However, the same three codes may be used for all assessors within a test, provided that each code is used only once per assessor during a test session (e.g. if several triangle tests on different products are being conducted in the same session). 5.6 It is preferable to present the samples under the conditions at which the product is generally used (e.g. in a taste test, present the samples at the temperature at which the product is generally consumed). The serving conditions of the three samples in each triad shall be identical (e.g. in a taste test, the three samples shall be served at the same temperature), just as that of all the other samples in a series of tests on a given type of product. 5.7 The size, quantity or volume presented shall be identical for the three samples in each triad, just as that of all the other samples in a series of tests on a given type of product. The size, quantity or volume to be evaluated may be imposed. If it is not, the assessors should be told to take sizes, quantities or volumes that are always similar whatever the sample. 5.8 In a taste test, the assessors shall be told whether or not they are to swallow the samples or whether they are free to do as they please. In this latter case, they shall be requested to proceed in the same manner for all the samples.
6 Assessors 6.1? Qualification All assessors should possess the same level of qualification, this level being chosen on the basis of the test objective (see ISO 8586 for guidance). Experience and familiarity with the product may improve the performance of an assessor and, therefore, may increase the likelihood of finding a significant difference. Monitoring the performance of assessors over time may be useful for increased sensitivity. All assessors shall be familiar with the mechanics of the triangle test (i.e. format, task and evaluation procedure).