Milk: From the Cow To You

The Science

Milk is made up of over 80 % water. Cow and goat milk is 87% water, and sheep milk is 83% water. The remaining percentage of milk is made up of milk fat, milk sugar (lactose), milk protein (primarily casein) vitamins, minerals, and other trace elements.

Pasteurization versus Homogenization: What’s the difference?

In the 1850’s, a French scientist named Louis Pasteur discovered that heating various liquids, including milk, postponed souring and prevented disease-causing bacteria from multiplying. Pasteurization is the process of heating milk to a high temperature and then cooling it rapidly. This process was not started in the United States until after 1900, when new technology allowed for large scale pasteurization. Still, the process did not become popular until after World War II when home milk delivery declined and consumers needed their milk to stay fresh longer than only a day or two. For health reasons, as well as convenience, pasteurization is important.

Homogenization breaks down the fat particles in milk so that they are evenly dispersed throughout the milk. Homogenization was developed in the 1890’s but was not commercially used until the 1920’s. Milk that is not homogenized separates into fluid skim milk and cream but is still safe to drink. Homogenizing milk assures that each sip of milk is the same as the one before.