Food vary widely in their lipid content and composition. Lard, shortening and vegetable or animal cooking fats and oil content almost 100% lipid. The fat content of butter and margarine is about 81% and of commercial salad dressings 40-70%. Most nuts are very rich in lipids (almonds 55%; cashews 46%; etc) Fresh, fluid cow's milk has 3.7% fat, but after drying 27.5% fat. In cereal product : grains contain only 3-5% but the germ around 30% : bread 3-6%. Most fruits; and vegetables contain small amounts of lipids (but some fruits : e.g. avocado contains 16% lipid) There is no single standard for lipid extraction. The method used depends on the type of analyzed material and nature of the subsequent analytical problem. Vats can be conveniently determined in food by extraction the dried ground sample with light petroleum or equivalent solvents in a continuous extraction apparatus called a Soxhlet. In analysts before a petroleum ether extracted. The hydrolysis the portion of lipopolysaccharidc, lipoprotein and other lipid conjugates.