The margarine that many people use instead of butter is made out of vegetable and animal fats, along with skim milk and salt. The fats account for about four-fifths of the margarine, and the milk and salt for the rest.
Margarine was invented by a French chemist during the 1860s. Most margarine sold in the United States is now made from vegetable oils, such as soybean, cottonseed, peanut, or corn oil.
The melted fats are churned together with the milk, chilled to form a solid, then kneaded into shape by machines and packaged.