Deuteronomy 32:38 "Who eat the fat of their sacrifices, and drink the wine of their libations"

This Negative Mitzvah prohibits us from drinking the wine of non- Jews that has been used for idol worship.

Our Rabbis added to this commandment and forbade the drinking of any wine which has been made or touched by non-Jews. Such wine is called "S'tam Yaynum".

Through this Negative Mitzvah, as with some others, we can see that "kosher" does not only mean the ingredients that go into a product. Food can become non-kosher in the way it is prepared or handled.