Question :

What is the ruling on eating the food prepared by Christians friends knowing that their income comes from trading in alcoholic drinks?

The Answer :

Praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.

It isn`t allowed to have the food of the person whose source of income is unlawful. However, if it is a mixture of lawful and unlawful, then it is permissible to have their food. And Allah the Almighty knows best.