Selection of Panellists With a Modified ETOC Test
N.T.E. Holthuysen*, M.A. Nijenhuis, J. Mojet
WUR-CICS, The Netherlands
To screen persons for participation in a descriptive sensory panel, the European Test of Olfactory Capabilities (ETOC), provided by the Department of ‘Neurosciences et Systèmes Sensoriels’ of the University of Lyon (France) was chosen. This test has been developed as a negative discrimination test, i.e. to identify people with decreased olfactory sensibility. In the present study it is modified into a positive discrimination test, so that the most sensitive persons can be selected.
The original test procedure contains sixteen familiar food and non-food odours, presented in 16 sets. Each set consists of one odour-filled and three empty vials. A subject has to indicate which of the four vials contains an odour (detection) and subsequently, which descriptor, from a list of four descriptors, is appropriate (identification).
Because the original ETOC test was not designed to discriminate between sensitive and highly sensitive persons, the test was adjusted to do so. The first part of the test is still the same. The subject has to detect the odour in one out of 4 vials (detection). In the second part, the subject has to select the descriptor that best describes the quality of the perceived odour, but now from a list of twenty-two descriptors instead of four (identification).
Two hundred sixty-eight subjects took part in this study. With an average of 15.5 correct responses out of 16, the odour detection task proved to be not discriminative. However, the odour identification task discriminated well between the subjects. The average score was 9.9 out of 16, with a range of 1 to 16 (normal distribution). The selection criterion for participation in a descriptive panel was set to a minimum of 12 correctly identified odours (28%). The modified ETOC procedure seems to be an appropriate tool for the selection of subjects for a descriptive panel.