Bikkurim, Chapter Two, Mishnah One
The first four mishnayot of this chapter compare the rules governing bikkurim with those governing terumah and maaser sheni.
Regarding terumah and bikkurim:
1) One is liable to death
2) And the [additional] fifth;
3) And they are forbidden to non-priests;
4) And they are the property of the priest;
5) And they are neutralized in a hundred and one parts;
6) And they require the washing of hands;
7) And the setting of the sun.
8) These [laws] apply only to terumah and bikkurim, but not to tithe.
Section one: A non-priest who intentionally eats terumah or bikkurim is liable for death by the hands of heaven. He is not executed by a human court.
Section two: If a non-priest eats them unwittingly, when he discovers what he has done he must restore the value plus an added fifth (see Terumot 6:1-2).
Section three: We already know this from sections one and two. It is taught here so that when we read section eight, we will understand that tithes are permitted to non-priests.
Section four: Bikkurim and terumah are the personal property of the priest who receives them and therefore he can use them to buy any thing he wishes, as long as the person who ends up eating them is also a priest.
Section five: If one part bikkurim or terumah fall into one hundred parts hullin (non-sacred produce), one can remove one part, give it to the priest and the rest remains hullin. If there is less than 100 parts hullin, then the mixture is doubtful terumah/bikkurim and cannot be eaten by a non-priest.
Section six: One who comes to touch bikkurim or terumah must first ritually wash his hands.
Section seven: Before an impure priest eats terumah/bikkurim he must first go to the mikveh to purify himself. Afterwards he cannot eat them until the sun sets (see Leviticus 22:7).
Section eight: All of these laws apply only to terumah and bikkurim. When it comes to maaser sheni (second tithe), a non-priest can eat them, one can use maaser sheni money to buy only food, drink or anointing oils (see Maaser Sheni 1:7), and if maaser sheni falls into a mixture, as long as it is less than half the mixture, it is nullified. First tithe is treated like hullin in all ways, except that it must be given to the Levite.