Annaliese Wegner, Dairy farmer, in an Aug. 7, 2017 article for titled "There Is No Pus in Milk," wrote:

“There is NOT pus in your milk. Sure, animal activist groups would like for you to believe that there is pus in milk, but what they are actually referring to is the level of white blood cells in milk.

White blood cells are infection fighters in the body. An elevated white blood cell count may indicate that the cow is fighting an infection, such as mastitis… The presence of white blood cells does not indicate a sick animal; some white blood cells are normal. Only when we see high levels of white blood cells does it become an issue. This is true of organic milk and conventional milk. Dairy farmers closely monitor white blood cell count and refer to it as Somatic Cell Count (SCC).

SCC is the main indicator of milk quality in the dairy industry, and farmers work hard to keep a low SCC… While the legal SCC limit in the U.S. is 750,000, most dairy co-ops and creameries require a SCC below 400,000. Because dairy farmers are financially rewarded for low herd SCC and penalized for high ones, most strive to have a SCC below 200,000.

Every load of milk is quality tested when it reaches the creamery to ensure that the milk you put on your table is the very best quality! In addition to SCC, milk is regularly tested for antibiotics and protein and fat content… There is not pus in your milk; just, normal white blood cells.”

Aug. 7, 2017