Evaluation of measurement uncertainty for the methods of analysis used to assess the characteristics of olive oil and olive-pomace oil from commission regulations EEC 2568/91 and EC 1989/2003

Abstract

Metrology has been present in our scientific knowledge for a long time, but mostly in physical measurements. Chemical measurement can be defined as a comparison of a quantity of measurand and relating it to a unit (e.g. mol/kg).When expressing a result of a measurement, the problem of traceability, validation and the measurement uncertainty (MU) evaluation must be challenged. It is well known that MU is a parameter associated with the result of a measurement that characterizes the dispersion of the values that could reasonably be attributed to the measurand. The EEC document 2568/91 with its annexes gives the methods of analysis to assess the characteristics of olive oils and olive-pomace oils with given limits. The EC document 1989/2003 gives the scheme, the algorithm, the pathway, the decision tree to differentiate between various types of olive oils using the particular determinations based on limits. The major lack of these EC methods is the non-existence of validation parameters, which are crucial in determining the MU (and in accreditation of a laboratory). There are several ways of evaluating (better term than calculating) the MU: with model equation, with use of a certified reference material (CRM) and with participation in a proficiency testing (PT) scheme. MU for a method of analysis is inherent to a laboratory and can serve as a tool for \u27measuring\u27 the quality of a laboratory. Unfortunately, there are practically no CRM\u27s in the olive oil testing field. The only way to achieve a usable MU is through participation in PT schemes