OLEUM Interlaboratory validation process
One of the goals of OLEUM is to produce new methods that can be used by laboratories to measure compliance with EU standards for olive oil.
In order to be able to be used for official purposes the methods have to go through rigorous method validation and standardisation processes:
- The developed methods have to be in an internationally accepted format
- They have to undergo formal validation “in-house” to internationally accepted standards
- They have to undergo formal interlaboratory method validation to internationally agreed procedures
To do this latter process we have adopted a two-stage procedure:
The aim of the pre-trial study is to expose participants to the new methodology by sending them two samples (i.e. test materials) and to receive feedback in terms of their results but also, just as importantly, their comments or suggestion of improvement on the method.
A key part of the pre-trial that we have included within OLEUM are workshops where participants (skilled or olive oil analysis beginners labs) share their experiences with the developers and provide feedback on the method so that any errors can be corrected and changes can be made that make the method more-easy to understand and use.
Method performance statistics are calculated from the submitted data and used to anticipate the final validation results and serve as a useful decision point in terms of whether the candidate methods should go to the final stage (trial proper).
B) Trial proper
In this more formal phase, participants use the method, revised from the pre-trial, to analyse a group of “blind samples”, usually ten samples (i.e. test materials). The method performance characteristics are calculated on the reported results and used to assess whether the method is suitable for use for official purposes. A minimum of eight laboratories are normally required for such a study but OLEUM aims to have significantly more than this for the 4 studies that are being undertaken.
Progress to date:
OLEUM is proposing to validate new procedures in 4 areas:
- Polar phenols analysis used for assessing the olive oil health claim
- Free and esterified sterols analysis targeting illegal olive oil blends
- Improved methodology for fatty acid ethyl esters targeting illegal processing or lower quality virgin olive oil
- Sensory and volatiles analyses for quality and authenticity of virgin olive oil
All have undergone pre-trials and have been discussed at knowledge transfer workshops in Seville (October 2019) and Bologna (December 2019).
We are now finishing our preparations for the trial proper studies that will be taking place in the next few months.
For further information on this work please contact Martyna Korytkowska at M.Korytkowska@qub.ac.uk.