Development of a certified reference material for polycyclic aromatic hydrocarbons (PAH) in olive oil

Like all edible vegetable oils, olive oils can be contaminated with lipophilic organic pollutants such as polycyclic aromatic hydrocarbons (PAH). Olive oils are susceptible to PAH contamination, typically due to combined effects including environmental pollution, oil processing, and migration from food contact materials. Monitoring PAH levels in olive oil is therefore essential to ensure food safety and consumer protection. According to Commission Regulation 2023/915, maximum levels have been set for certain PAH: 2 µg kg^-1 for benzo[a]pyrene (BaP) and 10 µg kg^-1 for PAH-4, representing the sum of BaP, benz[a]anthracene (BaA), benzo[b]fluoranthene (BbF), and chrysene (Chr). However, no certified reference material (CRM) is currently available containing PAH-4 at the regulated maximum levels. To address this deficiency, the first CRM for PAH-4 in extra virgin olive oil (BAM-A001) was developed based on the requirements of ISO 33405. BAM-A001 is intended to be used for performance evaluation and validation of analytical methods for the determination of PAH in olive oil and similar vegetable oils. The entire CRM development process including preparation, homogeneity and stability studies, and value assignment is presented. The certified mass fractions of BaP (1.44 µg kg^-1) and PAH-4 (7.33 µg kg^-1) were determined upon in-house study at BAM using stable isotope dilution analysis gas chromatography mass spectrometry (SIDA-GC-MS). In addition, BAM-A001 underwent secondary characterization for lead (Pb) and cadmium (Cd) levels, acknowledging an EU regulation allowing a maximum of 0.1 mg kg^-1 Pb in oils and fats.