Avodah Zarah 29 - Prohibition of the Wine and Cheese of Idolaters
The following items of idol worshippers are prohibited not only for consumption, but even for benefit: wine, wine that turned into vinegar, and wine vessels that absorbed wine. Wine is prohibited because of two reasons: it may have been poured for idol worship, and it leads to socializing and intermarriage.
Cheese of idol worshippers - Rabbi Meir considers it prohibited for any benefit, but the Sages forbid only eating it.
Rabbi Ishmael asked Rabbi Yehoshua while they were traveling on the road, "Why did the Sages prohibit the cheeses of idol worshippers?" Rabbi Yehoshua answered, "Because they use the rennet of animals that was not properly slaughtered." "But a sacrifice is stricter, and its rennet is not prohibited!" "Because they curdle it with the rennet of the calves of idol worship," - said Rabbi Yehoshua. "But then it should be prohibited for benefit, and it's not!?" Instead of answering, Rabbi Yehoshua diverted the conversation to another topic, about the correct reading of "... since your love it better than wine " from the Song of Songs.
Art: Raphaelle Peale - Cheese and Three Crackers