What Makes Milk White?

When light hits the tiny micelle particles it causes the light to refract and scatter. This causes milk to reflect all light wavelengths and absorb none, making it appear white.

What do they put in milk to make it white?

Caseins are one of the main types of protein in milk which cluster together with calcium and phosphate to form tiny particles called micelles. When light hits these casein micelles it causes the light to refract and scatter resulting in milk appearing white.

Why milk is white not green?

So why is milk white and not green for example? Because there are so many fat and protein molecules in milk that enough light at all wavelengths gets scattered giving the appearance of white light. If all the wavelength of the light would get absorbed, milk would be black. The color also depends on what the cow eats.