Al-hamdu lillah (praise be to Allah). There is no objection for a Muslim to eat from food that a kaafir (unbeliever), whether polytheist or otherwise, has cooked, as the issue of cooking does not involve slaughtering according to Islamic guidelines so that we would require the person to be from ahl il-kitaab (People of the Book) among the kuffar. In fact, it is only a matter of cooking, so the only issues that concern us are cleanliness and the avoidance of najasa (impurity), and likewise that nothing haram (forbidden) is mixed with the food such as khamr (wine or alcoholic beverages) or lard.
May Allah protect us from harm, evil and the things he has forbidden (al-muharramaat).
Sheikh Muhammed Salih Al-Munajjid