From the site:

Have some … pus with your cookies? If you down a glass of cow’s milk, you will. It may be white, but researchers say that every cupful contains somatic cells, i.e., pus.

The dairy industry knows that there is a problem with pus in milk. Accordingly, it has developed a system known as the “somatic cell count” to measure the amount of pus in milk. The somatic cell count is the standard used to gauge milk quality. The higher the somatic cell count, the more pus in the milk. [more]