A priest who eats from an offering before the sprinkling of the blood gets lashes.

Why is this?

The passuk implies a lo taaseh in a taaseh which gives it the status of a lo taaseh which, if violated gets lashes. 

Rava's challenge: Then why does it need to say when talking about kashrut the animals you can eat directly followed by the animals you cannot eat? Can we say the lo taaseh is implied?

We cannot say that because in a case of a lo taaseh implied in a taaseh, if the taaseh does not apply to the person, then the lo taaseh does not apply as well and we cannot punish him for violating it. 

Regarding the first fruit ceremony:

Rabbi Eleazar said in the name of Rabbi Hoshaia that if you don't set the fruit in front of the altar you cannot eat it but if you don't do the recital (but do set it in front of the altar) you can. Did Rav Hoshaia really say that? Isn't the reason if they are not set in front of the altar they are left to rot BECAUSE the recital was not done on them? This is in accordance to Rav Zera's statement who says wherever the conditions for mingling [oil with flour for a meat offering] are present, the omission of the mingling is not a bar. However, wherever they are not present, the omission is a bar [Therefore, not putting them on the altar would be a bar here because the conditions for a meat offering are not present]. 

Rav Aha bar Jacob taught a similar statement in the name of Rav Assi reporting for Rabbi Yonatan. Rav Yonatan made a seemingly contradictory statement in which he said that for the fruit that were brought at the proper time of the recital, they can be eaten right after the recital (implying that both the recital and the placement on the altar are necessary for the eating of the fruit) but for the fruit that are brought after the proper time, they may be eaten right after they are brought to the temple (implying that both the recital and the placement are not instrumental to the permissability of eating the fruit). The gemara rectifies these contradictions, saying the first contradiction [in regard to the recital] is the difference in opinion between Rav Simeon and Rabbis, while the second contradictions [in regard to the placement on the altar] is the difference in opinion between Rav Judah and Rabbis.

NOTE: RAV JUDAH HOLDS THAT THE PLACEMENT ON THE ALTAR IS NOT NECESSARY FOR THE FRUIT TO BE EATEN.

The Gemara asks for the statement of Rav Judah that this is referring to. The statement brought: And the priest shall take the basket out of thy hand and set it down before the altar- the phrase set it down teaches us that the placement is not necessary (set it down refers to a ceremony called 'waving' not ordinary placing and therefore does not teach us we need the placement). The Gemara asks which Tanna disagrees with Rav Judah and brings up Rabbi Eliezer bar Jacob who says we do need the placement because set it down does NOT refer to waving, rather, ordinary placement in front of the altar. 

How do you think the Gemara gets from the punishment of a priest who eats a korban too soon to the process of bichurim? 

Sorry the post is late and sorry if it is confusing, I don't have a great translation of the Gemara and my first summary deleted itself so I had to write a new one :(. Hope its acceptable!!