Peroxide value of olive oil: the new IOC method (COI/T.20/Doc. No 38) replaces chloroform with isooctane and allows potentiometric titration — the EU backed it with Decision (EU) 2026/711
Council Decision (EU) 2026/711 of 16 March 2026, published on 20 March, sets the Union position in the Council of Members of the International Olive Council (IOC): support for a new method for determining the peroxide value of olive oils and olive pomace oils as a safer alternative to the current COI/T.20/Doc. No 35, and for an amendment to trade standard COI/T.15/NC No 4. The IOC published the method text dated February 2026.
- In method Doc. No 35/Rev.1 (2017) the sample was dissolved in chloroform and acetic acid, and potassium iodide reacted for 5 minutes in the dark. Doc. No 38 dissolves the sample in 50 ml of a glacial acetic acid/isooctane mixture (60:40) made from degassed reagents; after adding saturated KI solution it is stirred for exactly 60 s, water is added and the liberated iodine is titrated with 0.01 mol/l sodium thiosulfate.
- The end point is determined visually with starch or potentiometrically with a combined platinum electrode in an automatic titrator. Test portion: 5.0 ± 0.1 g for an expected peroxide value from > 1 to 30 and 10.0 ± 0.1 g for 0–1; the blank may not consume more than 0.1 ml of titrant, and the result is reported to one decimal place.
- The thiosulfate titre is determined against potassium iodate traceable to NIST. Precision data come from DIN interlaboratory studies for ISO 3960 and ISO 27107: for an extra virgin olive oil with a mean of 12.04 meq/kg the repeatability limit r was 0.73 and the reproducibility limit R 3.00 meq/kg (iodometric method, 22 laboratories after removing outliers).
- The trade standard amendment adds the Coratina variety to Koroneiki and Nocellara del Belice in the footnote on total sterol content in monovarietal extra virgin olive oils. The IOC decisions were to be taken by exchange of correspondence before the 123rd session of the Council of Members in June 2026 or at that session.