Upper middle class. Shilimei is a well-known snack food brand, mainly engaged in slimming plum, delicious sour plum, dried blueberry, preserved apricot and other snack foods. Prune is the main component of Prunus mume, which is an imported fruit, originated in southwest France and later introduced to California in North America. At home, foreign fruits are generally expensive, so it is natural to import prunes.