Food
Within the Imperium, entire worlds are devoted to agriculture and food, providing the necessary sustenance for populations elsewhere in the galaxy. These agri worlds can grow a variety of food in a variety of ways, from the ill-tempered grox that provide meat to simple wheat for bread, with entire continents being given over to the growth of foodstuffs. This variety can produce confusion when Imperial cultures mix; in one recorded instance, a local of Vervunhive mistakes camo-paint as a type of food eaten by the off-world Tanith regiment.
http://wh40k.lexicanum.com/wiki/Food_and_Drink_of_the_Imperium