<p>Amethod is provided for preservingcooking oilwhich may be cold or heated or during fryingoperations, which comprises in situtreatment of the oil withat least one oil- permeable cement bodywhich has been hydraulically hardened from a paste comprising cement clinker and cement e.g. white OPC clinker and white OPC. The invention further comprises cooking oil having therein at least one oil-permeable cement body which has been hydraulically hardened from a paste comprising cement clinker and cement and an oil-permeable cement bodyfor use in the above method.</p>
