286 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS question will need to be asked, i.e. for flavour preference, and a rating scale can be used of the following form: 0 1 2 3 4 Very poor Poor Average Good Very good Other flavour description questions can be asked if it is wished to con- sider the influence of particular flavour sensations on acceptability. Because of the obvious variability of flavour likes and dislikes over the population, panels used for acceptability testing must be large and as representative of that population as possible. Panel size should be at least 50 and local panels confined to a single factory or workplace would seem to be unsuitable because unrepresentative, although they could be used for a first rough screening of fiavours for acceptability. Experimental design can be built into the testing by using different levels of a range of flavour components. Regression analysis can again be used and linear programming or inspection used to detect flavour combina- tions with optimum flavour preference ratings, the object of the testing being no longer to match a standard, but to optimize flavour preference. CONCLUSIONS The test procedures described above are intended to enable flavour evaluation, particularly description, to be carried out in an orderly and scientific manner. Emphasis has been placed on the generation of numerical results which can be subjected to statistical analysis. The numerical pre- scriptions applied to flavour acceptability have been deliberately left some- what vague. In this area the ideas for new flavours will usually come from a creative flavour specialist although panel testing will be necessary to judge the success of his efforts. (Received: 17th January 1975) REFERENCES (1) Fruchter, B. Introduction to factor analysis (1954) (Van Nostrand, Princeton). (2) Moncrieff, R. W. 'Gustation', Food Mfr, June, 1944, p. 203. (3) A.S.T.M. Publication S.T.P. 433. 'Basic principles of sensory evaluation' (1968). (4) Moncrieff, R. W. 'The tastes', Perrum. Essent. Oil Rev. (Oct 1950 to Feb. 1951). (5) Harris, H. Introduction to human biochemical genetics (1955) (Cambridge, London). (6) Wells, F. V. 'Duration of odorants on the skin'. S.P.C. Year Book, 107 (1966) (United Trade Press, London).

EVALUATION OF FLAVOURS IN DENTAL CREAMS 287 (7) Pfaffman, C. 'Symposium on food acceptance testing methodology'. Quartermaster Food Container Inst. 6 (Oct. 1954). (8) Perryman, D. R. and Swartz, V. W. 'Measurement of sensory difference'. Food Technol. $ 207 (1950). (9) Cairncross, S. E. and Sjostrom, B. L. 'Flavour profiles--a new approach to flavour problems'. Food Technol. 308 (Aug. 1950). (10 McBurney, D. H. 'Are there primary tastes for man?' Chem. Senses Flavour I 17 (1974). (11) Jolson, M. A. and Rossow, G. L. 'The Delphi process in marketing decision making'. J Market. Res. VIII 443 (1971). (12) Cochran, W. G. and Cox, G. M. Experimental designs (1950) (Wiley, New York). (13) A.S.T.M. Publication S.T.P. 434. 'Manual of sensory testing methods (1968). (14) Davies, O. L. Design and analysis of industrial experiments (1954) (Oliver and Boyd].