The present invention relates to a process for refining glyceride oil comprising the steps of: (i) contacting glyceride oil with a liquid comprising a basic quaternary ammonium salt to form a treated glyceride oil; wherein the quaternary ammonium salt comprises a basic anion selected from hydroxide, alkoxide, alkylcarbonate, hydrogen carbonate, carbonate, serinate, prolinate, histidinate, threoninate, valinate, asparaginate, taurinate and lysinate; and a quaternary ammonium cation; (ii) separating the treated glyceride oil from a salt comprising the quaternary ammonium cation; and (iii) subjecting the treated glyceride oil after the separation step to at least one further refining step; and to the use of contacting a glyceride oil with the basic quaternary ammonium salt for preventing or reducing the formation of fatty acid esters of chloropropanols and/or glycidol upon heating of the glyceride oil.