(Mishnah in Maseches Eduyos): R. Yosi - In six cases, Beis Shammai were lenient and Beis Hillel were stringent...Fowl may be brought to the same table as cheese but may not be eaten. Beis Hillel say that it may not brought or eaten.

Beis Shammai say that one may separate Terumah from olives for oil or from grapes for wine. Beis Hillel prohibit it. (This implies that according to Beis Hillel, if it was done, it is valid.)

Answer (R. Mana): The Mishnah should not have the words "olives for oil''; rather it should say "oil for olives'', as was taught by R. Yosi.

When the Mishnah taught, "It is valid Terumah, but he must separate again'' - that's only when the first Terumah no longer exists, but if it does, he must merely declare the second one as Terumah.

(Baraisa): The second Terumah may not be eaten until it has correctly had its Terumah and Ma'asros taken.

Question: Must the Kohen separate Ma'asros for the first Terumah?

Answer (Tosefta): (If one separated Terumah from olives for olives that are for pressing or grapes for grapes that are for pressing, it is valid, but he must separate again.) And if the Yisrael then made the first ones (and the Kohen made the Terumah ones) into oil or the grapes into wine, he declares the first Terumah to be Terumah again and he does not need to separate a second Terumah.

This shows that he must separate and declare the Ma'asros even for the first Terumah.