Although the milk you get from the supermarket is uniformly white, every dairy farmer knows this is a far cry from the natural color of fresh cow’s milk.
When milk first comes out of the cow, it’s more yellow in color than the white pasteurized milk you find on the shelves. Contrary to some beliefs, the yellow tinge in fresh unpasteurized milk is due to the mineral beta carotene, which is found in cows’ feed, and absorbed into the fat found in their milk.
In this article, we’re going to look more closely at the color of cow’s milk, especially the color of natural cow’s milk, and why it’s a different color than store-bought milk.
What Color is Natural Cow’s Milk?
Natural cow’s milk is a light yellow color, more similar in color to buttermilk than to store-bought white milk. This is due to the higher fat content found in natural milk, and the lack of homogenization which evenly distributes the fat throughout the milk.
In natural cow’s milk, the fattier milk separates and rises to the top, forming a yellow layer on the surface and leaving the paler, whiter milk below.
Part of the process of getting milk ready for human consumption is a process called homogenization. Homogenization passes the milk through a very fine screen at high pressure, which breaks apart the fat and spreads it evenly throughout the milk.
Homogenized milk doesn’t separate as easily and doesn’t develop a fatty layer on the top of the milk.
Read More: Do Cows Enjoy Being Milked?
Why is Natural Cow’s Milk Yellow?
Natural cow’s milk is yellow because of a particular mineral found in cows’ diet called beta carotene.
Beta carotene is fat-soluble, which means it lends its yellowish color to the fat found in natural milk before the fat is skimmed off and the milk is pasteurized for human consumption.
Fun Fact: Natural milk produced in summer tends to be even more yellow in color than milk produced in winter because there is more beta carotene in the fresh grass that cows feed on during the summer than in the dried hay which they are fed during winter.
Read More: What do Cows Eat?
Why is Cow’s Milk White?
According to the International Dairy Foods Association, milk is around 87% water.
The remaining 13% are made up of tiny solid particles of minerals and proteins, which scatter the light in all directions, causing the milk to appear white.
Before milk hits the shelves, it goes through two processes that contribute to milk’s white color:
1. Skimming
Fat is skimmed from the top of the milk. Since the fat is what gives milk its yellow tinge, this process leaves behind the more pale milk.
2. Homogenization
Once the milk has been skimmed, it is homogenized. This process pressurizes the milk and passes it through a very fine screen, forcing any large fat particles to break apart into smaller, more evenly sized particles.
This prevents the milk from separating and forming a yellow layer near the top of the milk, instead keeping the milk an even white color throughout.
Is Cow Milk Naturally White?
Cow’s milk is not naturally white. When fresh milk is first extracted from the cow, it’s a yellowish color more akin to buttermilk. Through the process of skimming and homogenizing the milk for human consumption, the milk ends up whiter and more consistent.
Does Milk Contain Blood or Pus?
Over the years, there have been many scare stories and urban myths around milk, including that milk contains blood, pus, or even poop.
Let’s take a look at some of these claims and see if there’s any truth to them:
Does Cow’s Milk Contain Pus?
One of the most common claims around milk is that cow’s milk contains pus and that’s why it’s yellow.
Pus is a horrible mixture of dead skin, bacteria, and dead white blood cells which every mammal creates to fight off infection. It is NOT found in milk, and there are strict testing requirements for all milk to make sure milk from sick cows can never enter the food chain.
Does Cow’s Milk Contain Blood?
Cow’s milk doesn’t contain any actual blood, but it does contain a small number of white blood cells.
White blood cells are present in all animal products, including all meat and dairy products.
How Much Blood is in Cow’s Milk?
White blood cells are found in all animal products and are perfectly harmless, however, an increased level of white blood cells in milk can indicate that a cow is fighting off an infection.
Farmers use a measurement called BTSCC (Bulk Tank Somatic Cell Count) to measure the white blood cell count. This measure effectively calculates the number of individual somatic cells found in each milliliter of milk (before pasteurization).
According to the FDA, most dairy operations in the US have a somatic cell count (BTSCC) of between 100,000 and 300,000 cells per ml of milk, which is well below the standards set by the FDA.
In a 2003 study by researchers at Cornell University, a goal of 200,000 cells/ml was proposed in order to maximize udder health and reduce incidences of mastitis.
Comparison of Maximum SCC regulations for cow’s milk in different jurisdictions:
| Jurisdiction | Maximum SCC | Source |
| United States | 750,000 cells/ml | FDA – Pasteurized Milk Ordinance |
| Canada | 400,000 cells/ml | Farm Products Marketing Act (2007) |
| European Union | 400,000 cells/ml | European Council Regulation 834/2004 |
Does Pasteurization Change the Color of Milk?
Pasteurization does not change the color of milk, however, milk does go through several other stages of processing before pasteurization including skimming and homogenization, both of which do change the color of milk.
Does Cow’s Milk Contain Artificial Colors?
Regular cow’s milk that you can buy in the supermarket does not contain any artificial color, however, some sweetened milk or milkshakes may contain chemical colors, preservatives, or sweeteners.
Is Cow’s Milk Dyed White?
Cow’s milk is not dyed white. Cow’s milk is naturally white in color after it has been through the homogenization and skimming processes.
Conclusion
Cow’s milk is naturally yellow, due to the beta carotene mineral found in grass and dissolved into the fat of cow’s milk.
The reason cow’s milk changes from yellow to white before it hits the shelves is that excess fat is removed from cow’s milk by a process called skimming, and the remaining milk is homogenized, which means the fat is broken up and dispersed evenly throughout the milk.
Milk is only yellow due to the dissolved minerals in the fat, and not due to any unwanted additives like pus or blood.
Stuart is the editor of Fauna Facts. He edits our writers’ work as well as contributing his own content. Stuart is passionate about sustainable farming and animal welfare and has written extensively on cows and geese for the site.