At the outset of their training into the service of the king Babylon, Daniel and his companions are to be given a daily portion of royal food and wine from the king's table. Daniel 1:8 then says:
But Daniel resolved not to defile himself with the royal food and wine, and he asked the chief official for permission not to defile himself this way.
There is nothing in the text I can see to indicate that the food was from unclean animals, and I know of nothing that would make wine unclean. Why does Daniel consider the food and wine to be defiling?