if the grease is recognizable then you should take out that rice. If you can’t tell and it is less than one-sixtieth of the whole pot of rice (which would even permit you to eat it with milk) then they do not have to wait six hours after the rice to eat ilk. However this is forbidden to pour a little grease in on purpose and tell them it is pareve.
Explanation:
The Gemara in Chullin 111b writes: Hot fish which were placed on a Besari plate, Rav says its forbidden to eat the fish with Kutach (milk) and Shmuel said it is permitted. Rav said itis forbidden since the meat imparts flavor to the fish and Shmuel said it is permitted since its a secondary flavor, the meat put flavor in the plate and plate put flavor in the fish (Nat bar Nat).
Shmuel permits the fish to be eaten with milk because the flavor is very weak. The Rishon argue if Shmuel permits only when he put hot fish on a plate but if he cooked the fish in a meat pot, no.
Tosfot quotes the Rivan who says it is only if he put fish on the plate but cooking even Shmuel agrees that it is forbidden to eat with milk. Tosfot argues the is also permitted and there is no difference.
The Shulchan Aruch (YOD 95:1) rules like Tosfot: Fish which was cooked or roasted in a clean meat pot, that there is o meat residue at all, are permitted to eat with kutach sine it is a secondary flavor of permitted food. If it wasn’t clean and there is more than one-sixtieth of the fish they are forbidden to eat with milk.
It seems from the Shulchan Aruch that if there is sixty times fish against meat it is permitted to eat with milk, that is it pareve. So rules R’ Akiva Eiger there.
It seems though that the Issur V’heter HaAruch argues: If a Kazayit of milk fell into water and was nullified. Then the water fell into meat even though there were less than sixty times of meat again the milk we don’t say the milk is reconstituted and the meat it is forbidden. It seems that even if the milk could be nullified itis forbidden to on purpose mix it with meat only if got mixed. The Rema quotes the Issur V’heter. The Shach and the Rema in Torat Chatat write that you may put the water in the with the meat even on purpose since it was nullified.
Even though the Rema quotes the Issur V’heter that it is forbidden to mix them, we don’t follow that, the Rema in Torat Chatat says it is permitted. So according to the Shulchan Aruch and the Rema, parve food which has more than sixty times milk or meat may be used as pareve without worry. So the rice could be eaten with milk if there were more than sixty times.
So writes the Kaf Hachaim (Yod 87:34): I saw those who are stringent not to eat sugar with meat since Goyim within it with goat milk and I saw my Rebbe ( the Arizal) eat I together. So writes the Radbaz in Teshuva (606) there is nothing to worry about with sugar and meat.
Therefore one may even eat the rice with milk (if there were sixty times) and the bachurim definitely don’t have to wait six hours to eat milk. That is as long as the grease is not noticeable because if so you must remove since that is not nullifiable.
The Pri Megadim writes that is forbidden to put milk in parve to eat it with meat, but the Knesset Hagedolah says it is fine. The Kaf Hachaim and Aruch Hashulchan forbid it.
