The canned corn was an item in The Cave playthrough that Ben's character, the Monk, always carried with him.
Through thick and thin they traversed the The Cave and when presented with the object of his desire, he left it for his can of corn.
The canned corn was first encounted when they met the Prospector, who threw it among many things at them.
Ben was fast decided to keep the corn for the rest of the game.
Later when they got stranded on an island they found another Can of Corn which Fraser took with him for the rest of the game.