Experimental and theoretical determination of pesticide processing factors to model their behavior during virgin olive oil production

- Need for individual processing factors to be addressed in Annex VI of 396/2005.
- Processing factors (PF) calculated for 104 pesticides using laboratory-scale model.
- The PF obtained have been related with log Kow values.
- An equation to model and estimate PF for olive oil is proposed.
- MRL values for pesticides in olive oil can be corrected with the PF obtained.

The purpose of the present work was the experimental evaluation of pesticides transfer to virgin olive oil during the production step and prediction of their processing factors, which could be eventually used for the calculation of maximum residue limits (MRLs) in olive oil from the MRLs set in olives. A laboratory-scale Abencor system was used for the production of olive oil from olives spiked with the 104 pesticides studied, three different chromatographic methods being used for the analysis of raw olives and the obtained olive oil: (i) gas chromatography-tandem mass spectrometry (GC-MS/MS) for GC-amenable pesticides; (ii) hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) for polar pesticides, and; (iii) reversed-phase liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) for low to medium polarity pesticides. Processing factors experimentally calculated were correlated to their octanol-water partitioning coefficient (log Kow), enabling the calculation of the equivalent MRLs in olive oil from the MRLs in olives, considering the percentage of oil extracted (oil yield) and the log Kow of each pesticide.