This part of GSO/ISO 15788 specifies a method for the determination of stigmastadienes in virgin vegetable oils containing low concentrations of these hydrocarbons, particularly in virgin olive oil. This method is applicable to all vegetable oils although measurements are reliable only where the content of these hydrocarbons lies between 0,01 mg/kg and 4,0 mg/kg. The method is suited to detecting the presence of refined vegetable oils (olive, olive pomace, sunflower, palm, etc.) in virgin olive oils, since refined oils contain stigmastadienes and cold-extracted oils do not.