Stability for olive oil control materials

For the reliability of analytical Quality Control Materials (QCMs), stability studies are essential. In spite of the importance of the stability studies, there is no article relating to QCMs of olive oil. This paper describes an intralaboratory stability study aimed for assuring olive oil QCMs concerning to the physical–chemical characteristics defined in Commission Regulation (EC) No. 1989/2003. The study concluded that, in storage conditions of darkness and low controlled temperature (0–8 °C), critical physical–chemical parameters of the olive oil QCMs, such as acidity level, peroxide value, K-values and total waxes, are stable at least during 24 months (2 years) with, in general, light variability and up trends. Theoretically, according to this study a homogeneous sample olive oil could be used as a QCM during two years if this material were stored in the dark and low temperature. Then, olive oil quality control testing laboratories have an alternative to dispose stable in-house QCMs for the control of their measurements.