Can one eat french fries fried in a deep fryer used to fry dairy foods such as Mozzarella Sticks after having eaten meat? Does one have to wait the standard 6 hours or are the french fries permissible to eat immediately?
Since the French fries were cooked in the same oil as the cheese, although the two were cooked at separate times, the French fries are still considered a “tavshil” of milk and considered cooked together with it. The halacha is that we wait six hours after eating meat, before eating milk or even a tavshil of milk.
Most poskim say to wait six hours after eating a tavshil of meat, i.e. potato from cholent, and that we should not even eat a tavshil of milk, i.e. a potato from a cheesy soup. These include, R’ A. Eiger on Rema Y:D 89-3, Yad Yehuda ( kotzar) 89-27, Chochmas Adam 40-13, Kitzuk Shulchan Aruch 10-10, Kaf Hachayim Y:D 89-57, Igros Moshe Y:D 2-26, M’Bais Levi 9 pg. 23. They would definitely say that after eating meat itself that one should not eat a tavshil of milk. Even the Mechaber that 89-3 a tavshil after a tavshil, only says so when what was eaten is only a tavshil of meat, but not when actual meat was eaten.