I once checked a suitcase with El Al that was 70 lbs of just meat and ice. I get to Israel, and they can't find my bags. 3 days later they deliver my 2 suitcases to my yeshiva. This was in August. You were able to smell the suitcase from nearly a block away.
have done it many times no problems. if it is frozen solid when you leave to the airport and you are flying direct you shouldn't have any problems (unless it gets lost)
Its cute how the OP asked about one thing (customs problem)and everybody is answering about something else. (the frozen problem) basically if the customs stop you, you will have a problem. (Though prob not too serious in Israel)