Olive oil: the IOC issued an SPME-GC method for volatile compounds indicating sensory defects and new guidelines for tasting panels
At the end of July 2026 the International Olive Council (IOC) released documents dated June 2026, including the new method COI/T.20/Doc. No 37 for determining volatile compounds in virgin olive oil by SPME-GC-FID/MS and new editions of guidelines for sensory analysis laboratories. By Council Decision (EU) 2026/1539 the EU supported amendments to organoleptic assessment documents at the 123rd session of the IOC Council of Members.
- The method covers 18 compounds: 15 of them form the minimum set of diagnostic molecules for fermentative and non-fermentative defects, e.g. acetic acid, ethyl acetate and ethanol for the “winey-vinegary” defect, ethyl propanoate for “frostbitten olives”, hexanal, nonanal and pentanoic acid for “rancid”, and three — (E)-2-hexenal, (Z)-3-hexenyl acetate and 1-hexanol — were included because of their relationship with the fruity attribute.
- The headspace compounds are collected on a 50/30 µm DVB/CAR/PDMS SPME fibre: 1.9 g of oil with 4-methyl-2-pentanol as internal standard (about 2.5 mg/kg) is equilibrated for 10 minutes at 40 °C and the fibre is exposed for 40 minutes. Separation runs on a 60-metre polar polyethylene glycol column, and detection uses FID or mass spectrometry — depending on the laboratory’s equipment.
- External calibration with the internal standard in refined olive oil uses two standard mixtures of 12 levels each, 0.05–10 mg/kg and 0.20–25 mg/kg; compounds are identified by mass spectrum or linear retention index (C8–C20 n-alkanes), and results are reported in mg/kg to three decimal places as the mean of triplicates. Precision was established in a 2019 interlaboratory study under ISO 5725 on five samples, including extra virgin and lampante oil.
- The new editions cover the sensory test room (COI/T.20/Doc. No 6/Rev.2: 20–28 °C, space for 10 booths, booths 0.75 m wide without a sink and 0.85 m with one) and internal quality control of panels (Doc. No 17/Rev.3: a guideline of checks on at least 9 % of samples, a reference material every month, taster precision and deviation numbers up to 2.0). Council Decision 2026/1539 concerned two documents: revision 2 of Doc. No 6 and revision 3 of Doc. No 5 on the tasting glass; IOC decisions feed into the EU’s conformity-check rules for olive oil.