Frying oil degrades during prolonged use above 180 °C and can cause the appearance of carcinogenic by-products. French regulations (decree 2008-184 of 26 February 2008) stipulate that vegetable oil must be changed when its polar compound content is higher than 25%. Beyond that, the oil is unfit for human consumption
To be able to use a cooking oil, the Total Polar Material must not exceed 25 %. Beyond, the oil becomes unfit for human consumption (decree n°2008-184 du 26/02/08).