Is it permissible for an elderly man to live alone with a female domestic worker?

It is forbidden for a man to be alone with a foreign maid, based on the saying of the Prophet, peace and blessings be upon him: "No man is alone with a woman but the third of them is Satan." An exception to this is if the man is an old, infirm person whose desire has ceased, or if the maid is young and not desired.