Measurement uncertainty in sensory analysis

Per Lea
Nofima Mat, Ås, Norway

The importance of measurement uncertainty has gained increased  acceptance within most fields of metrology – of main interest to food analysts are the fields of chemistry, microbiology and physics, commonly referred to as “hard” scientific disciplines. In this respect sensory analysis has been The Ugly Duckling of the pond, partly because the subject area is young compared to the disciplines above, but even more importantly because not all the concepts of traditional measurement uncertainty are directly relevant to sensory science. Also, according to some classifications sensory science is considered a “soft” science discipline, by many outsiders considered to be “beyond” a proper measuring regime. The literature on measurement uncertainty within specialized fields of application is abundant, often taking the form of guidelines published by accreditation or standardisation bodies. The specialized nature of these guidelines makes them a challenge to apply, involving a thorough thought process to separate what is useful from what is not. Googling for measurement uncertainty in connection with sensory analysis frequently leads to frustrations, as words involving “sens”  are more often used within physics – as sensors measuring some physical or chemical phenomenon. Still, there are many valuable lessons to be learnt from the way “lab-bench” scientists treats their uncertainties, as well as pitfalls to be avoided. The result is a design of a philosophical and statistical basis for the concept of measurement uncertainty within the field of sensory science and a practical collection of methods to answer questions like “how good are my sensory measurements?” The hope is that future guidelines on measurement uncertainty from accreditation and standardisation bodies will include advice useful also to sensory scientists, turning The Ugly Duckling into the beautiful full-fledged swan we all know it is.