The Maharam Chalaveh suggests that if bitul works by making the chometz as the dust of the earth, and, as such, one does not violate the isur of baal yoreh, then eating it should also be permitted. Similarly Rashi seems to say that there is not a problem eating the chometz of a goi. Tosafos does not argue with the essence of this statement except to say that by eating it it becomes yours and therefore ossur.
Do the achronim deal with these concepts?
shmuel siegel, Jerusalem
My reading of the Maharam Chalavah is that it should be Mutar b'Hanahah , but it will remain Asur b'Achilah because of "Achshevei."
However, as you note Shitas Rashi is that one does not transgress the Isur of Achilas Chametz when eating the Chametz of a non-Jew. The concept behind this is that "Chametz" which the Torah prohibited is "Chemtzo Shel Yisrael" and therefore if it does not belong to the Yisrael it is not the article which the Torah prohibited.
As for the question of Tosfos as to why the Yisrael is not Koneh the Chametz by eating it, see Ran (Nedarim 34b) Noda bi'Yehudah (Even ha'Ezer 2:77) and Oneg Yom Tov (#111). (See also Insights to the Daf for Pesachim 38:2.)
D. Zupnik