What is the symbolism of chewse?

Did you mean the cheese? I'm not sure the cheese itself is symbolic. The symbolic function of the mess in the cabin is worth exploring. Through this mess, Stevenson shows the lack of discipline in the pirate's behavior and also indicates heavy drinking. The broken locks serve as evidence that the pirates are after one thing, the treasure map, and have turned the ship inside and out looking for the desired map that will lead them towards their goal.