Before a soul falls, it cannot be harvested by the devils for their unique energy. This is one of the many widely known facts that Soul merchant 'Elvis' told Bartlett.
Moreover, devils don't need to eat to survive. They taste food or drink just for sensory pleasure. However, the devil jailers in the prison still provide food for the prisoners on time, as a starved prisoner is worth only one soul, while a living one has unlimited potential and is worth at least more than one soul.
Lunch (or possibly dinner or breakfast) is a thick, yellow-brown soup with some unidentifiable ingredients floating in it. There are gray leaves, skin of unknown creatures, and claw-like chunks of meat.
"Can this really be eaten?" Bartlett frowned, stirring the nauseating soup with a wooden spoon.