It's origin was produced on a rancho with goat's milk. Fermented then seasoned and flavored to taste. Infinite variations. Mexico's own form of a "yoghurt". Homemade from Oaxaca tastes entirely different from Jocoque de Jalisco. I don't know about the supermarket stuff.
My weakness is for rebanadas de mango dishidrato. Con polvo de chili rojo y jugo de limon.
Translated: Dehydrated mango slices, spiced with red chili powder and lime juice.
Some folks use sugar which acts as a preservative. I use concentrated ascorbic acid and Stevia. When I get back I think we're going to try going commercial -- that and mermelada de mango, low sugar. Dehydrating is the expensive and labor intensive part.