Heat the oil in a large soup pan and brown the pork. Add the onion, cumin, salt, pepper and chilies and stir for 2 minutes. Add garlic and the water, cover and simmer for 30 minutes. Add the potatoes and continue cooking till they are tender. Mix in the corn kernels, green pepper and lemon juice and reheat to boiling. Check the seasoning and ladle into soup bowls. Sprinkle fresh, chopped parsley over each serving.