Got this from Wonderopolis:
The truth is, cheddar cheese does not “turn” orange — it is dyed. In its natural state, cheddar cheese is a white or yellowish color.
To fully understand the colorful history of this cheese, though, we’ll need to take a trip to Cheddar, England, the birthplace of cheddar cheese! But first, let’s learn a bit about agricultural science…
What a cow eats determines the flavor of milk (and cheese). The natural color of the cheese can fluctuate according to a cow’s diet.
Milk contains beta-carotene, the same natural pigment that gives carrots their orange color. Pasture-fed cows produce milk with higher beta-carotene levels in the spring when their diet consists of fresh grass. As a result, their milk produces cheese with a deeper yellow color.
In the winter, when the cow’s diet consists mostly of hay, beta-carotene levels drop. Less beta-carotene means whiter cheese.
In the early days of cheddar cheese, cheese lovers couldn’t get enough cheddar. Even today almost 90 percent of all cheese sold in the United States is cheddar.
Although they may not have understood the science of cheese, people knew that yellow cheddar had a better flavor than other white cheeses. Cheddar became so popular, in fact, that cheese shops were able to charge more for their cheddar cheese.
Unfortunately, it wasn’t long before sneaky cheese makers realized that by adding a bit of dye to their white cheeses, they could trick people into thinking they were getting authentic cheddar cheese. The more yellow the color of the cheese, the higher the price.
Centuries later, we still recognize cheddar cheese as the orange cheese in the dairy aisle. It gets its color from the annatto tree, which grows in tropical regions in Central and South America.
Annatto seeds are ground into a red powder and used for coloring foods. Used to dye cheese for more than 200 years, annatto gives cheddar cheese the same color year-round.
Cheddar cheeses that have not been dyed orange are often referred to as “white cheddar” or “Vermont cheddar,” even though they may not have actually been produced in the state of Vermont.
- See more at: http://wonderopolis.org/wonder/why-is-cheddar-cheese-orange/#sthash.d8icLvMM.dpuf
Hope this helps, John