about breastmilk...any species?

Question

why does the breastmilk of most, if not all, mammals, come out white?

I think some people might be confused. I know all milk-producing animals are considered mammals but I didnt know if they all have white milk. As for the other part of the answers I've been getting, it's helped to some degree but instead of a chemical colour refraction type thing, I kind of meant about all mammals...why do all mammals(as far as I know) have white milk and not say...purple for one, white for another and red for a third...obviously their babies all have different nutritional needs.
Does this help? thanks.

Answer 1

The stuff that the others are saying about the light refraction is true. It is the fat reflects all light and a little protein reflects a bright yellow causing it to be a cream color. This is why half and half cream is "more white" than skim milk which appears "more translucent". Butter is yellow due to the structure in which the fat aligns with the proteins.

I wanted to add this fact because your wording of the question is odd. Only mammals have the ability to create milk. The root word from mammal is the same root word as the one for mammary (gland) where the milk is produced. All mammals and only mammals contain mammary glands, so only mammals can produce milk. This is the true definition of mammals, and this is why monotremes like platypuses are considered mammals even though they lay eggs.

Answer 2

Milk is a colloid of micelles: tiny globules of fat suspended in a watery solution that diffract light in all directions such that the suspension appears white.

Answer 3

Because the molocules refract all the colors of the spectrum giving it a white or cream color.