Avodah Zarah 35B

כאן קודם חזרה, כאן לאחר חזרה, ומשנה לא זזה ממקומה.

Here, with regard to the Mishnah in Ḥullin, Shmuel’s comment reflects the explanation of R' Yehoshua before R' Yehoshua’s retraction of the assertion that it is prohibited to derive benefit from the stomach contents of an animal carcass. There, with regard to the Mishnah in Avoda Zara, Shmuel’s statement is in accordance with the opinion of R' Yehoshua after his retraction of that claim. And although this indicates that the Mishnah in Ḥullin presents an outdated ruling that was later rescinded, a Mishnah does not move from its place. In other words, once it has been taught in a certain manner, the tanna will not change the text of a Mishnah in order to reflect a change of opinion, so as to avoid confusion.

רב מלכיא משמיה דרב אדא בר אהבה אמר: מפני שמחליקין פניה בשומן חזיר. רב חסדא אמר: מפני שמעמידין אותה בחומץ. רב נחמן בר יצחק אמר: מפני שמעמידין אותה בשרף הערלה.

The Talmud suggests additional reasons for the decree of the rabbis. Rav Malkiyya says in the name of Rav Adda bar Ahava: The cheese is prohibited because non-Jews smooth its surface with pig fat. Rav Ḥisda says: It is because they curdle it with vinegar produced from their wine, from which it is prohibited to derive benefit. Rav Naḥman bar Yitzḥak says: It is because they curdle it with sap that is subject to the prohibition against consuming the fruit of a tree during the first 3 years after its planting [orla].

כמאן? כי האי תנא, דתניא, רבי אליעזר אומר: המעמיד בשרף הערלה ⁠— אסור, מפני שהוא פירי.

Parenthetically, the Talmud asks: In accordance with whose opinion is Rav Naḥman’s claim that the cheese of non-Jews is prohibited because it is curdled in the sap of orla? The Talmud answers: It is in accordance with the opinion of this tanna, as it is taught in a Mishnah (Orla 1:7): R' Eliezer says: With regard to one who curdles cheese with the sap of orla, the cheese is prohibited, because the sap is considered to be fruit of the tree.