Luke Skywalker is seen taking the milk directly from one of the female Thala-Sirens that produce it, thereafter drinking it.
The green milk gets its color, believe it or not from beta carotene. Meanwhile, the blue milk is blue from spirulina.
Pandora The World of Avatar Drinks in Satu’li Canteen and Pongu Pongu
Walt Disney World Quick Service Restaurants Removing Plastic Lids from Drinks