אפילו תימא לא קדם וסלקו הוי מין ומינו ודבר אחר
You may even say that it is referring to a case where he did not first remove the piece of non-kosher meat or fish. Nevertheless, this is a case of a mixture of one type of food with its own type of food and with something else, i.e., the spices and broth in the pot.
וכל מין ומינו ודבר אחר סלק את מינו כמי שאינו ושאין מינו רבה עליו ומבטלו:
And in any case of a type of forbidden food mixed with its own type of food and with something else, disregard the food that is its own type, as though it is not present in the mixture, and if the amount of permitted food that is not its own type is sixty times greater than the forbidden food, the permitted food nullifies it. Rav’s ruling applies to a case where the forbidden piece of meat or fish imparts flavor to another piece before the spices and broth are added, and there is a total volume sixty times greater than the original non-kosher piece. Consequently, even if the amount of spices and broth is eventually sixty times greater than the original non-kosher piece of meat or fish, the entire mixture is forbidden, as the spices and broth are not sixty times greater than the two pieces of meat or fish which are now non-kosher.
מתני׳ נוהג בטהורה ואינו נוהג בטמאה רבי יהודה אומר אף בטמאה אמר ר' יהודה והלא מבני יעקב נאסר גיד הנשה ועדיין בהמה טמאה מותרת להן אמרו לו בסיני נאמר אלא שנכתב במקומו:
MISHNA: The prohibition of eating the sciatic nerve applies to a kosher animal and does not apply to a non-kosher animal. Rabbi Yehuda says: It applies even to a non-kosher animal. Rabbi Yehuda said in explanation: Wasn’t the sciatic nerve forbidden for the children of Jacob, as it is written: “Therefore the children of Israel eat not the sciatic nerve” (Genesis 32:33), yet the meat of a non-kosher animal was still permitted to them? Since the sciatic nerve of non-kosher animals became forbidden at that time, it remains forbidden now. The Rabbis said to Rabbi Yehuda: The prohibition was stated in Sinai, but it was written in its place, in the battle of Jacob and the angel despite the fact that the prohibition did not take effect then.
גמ׳ וסבר ר' יהודה איסור חל על איסור והתניא ר' יהודה אומר יכול תהא נבלת עוף טמא מטמא בגדים בבית הבליעה
GEMARA: The Gemara asks: And does Rabbi Yehuda hold that a prohibition takes effect where another prohibition already exists? But isn’t it taught in a baraita: Rabbi Yehuda says: One might have thought that the carcass of a non-kosher bird renders the garments of one who swallows it ritually impure when it is in the throat, similar to the carcass of a kosher bird.
תלמוד לומר (ויקרא כב, ח) נבלה וטרפה לא יאכל לטמאה בה מי שאיסורו משום בל תאכל נבלה יצא זה שאין איסורו משום בל תאכל נבלה אלא משום בל תאכל טמאה
Therefore the verse states concerning the impurity of carcasses of birds: “A carcass, or that which is torn of animals, he shall not eat to defile himself with it” (Leviticus 22:8). The verse indicates that only those birds that are forbidden specifically due to the prohibition: You shall not eat of a carcass, i.e., kosher birds that died without ritual slaughter, cause impurity in this manner. This serves to exclude any bird that is not forbidden due to the prohibition: You shall not eat of a carcass, but rather due to the prohibition: You shall not eat a non-kosher bird. This indicates that according to Rabbi Yehuda, the prohibition of eating a carcass does not take effect with regard to a non-kosher bird, because it is already subject to a different prohibition.
וכי תימא קסבר אין בגידין בנותן טעם ובטמאה נמי איסור גיד איכא איסור טומאה ליכא
The Gemara continues with its question: And if you would say that Rabbi Yehuda holds that sciatic nerves do not impart flavor, i.e., they do not have flavor and therefore are not classified as food, and even with regard to a non-kosher animal it is prohibited to eat the sciatic nerve because the general prohibition of eating a sciatic nerve applies, whereas the prohibition of eating non-kosher animals does not apply because the sciatic nerve is not considered food, this is untenable.
וסבר ר' יהודה אין בגידין בנותן טעם והתניא האוכל גיד הנשה של בהמה טמאה ר' יהודה מחייב שתים ור"ש פוטר
The Gemara explains: And does Rabbi Yehuda hold that sciatic nerves do not impart flavor? But isn’t it taught in a baraita: With regard to one who eats the sciatic nerve of a non-kosher animal, Rabbi Yehuda deems him liable to receive two sets of lashes, one for eating the sciatic nerve and one for eating the meat of a non-kosher animal, and Rabbi Shimon exempts him entirely from lashes. This indicates that Rabbi Yehuda holds that the sciatic nerve does have flavor.
לעולם קסבר יש בגידין בנותן טעם וקסבר נוהג בשליל דאיסור גיד ואיסור טומאה בהדי הדדי קאתי
The Gemara answers: Actually Rabbi Yehuda holds that sciatic nerves do impart flavor, and he also holds that the prohibition of eating the sciatic nerve applies to the sciatic nerve of an animal fetus. Consequently, although Rabbi Yehuda holds that a prohibition does not take effect where another already exists, one who eats the sciatic nerve of a non-kosher animal is flogged twice, because the prohibition of eating a sciatic nerve and the prohibition of eating meat from a non-kosher animal come into effect at the same time.
ומי מצית אמרת נוהג בשליל והתנן נוהג בשליל ר' יהודה אומר אינו נוהג בשליל וחלבו מותר
The Gemara challenges this answer: And can you say that Rabbi Yehuda holds that the prohibition of eating a sciatic nerve applies to the sciatic nerve of a fetus? But didn’t we learn in a mishna (89b): The prohibition applies to a late-term fetus in the womb. Rabbi Yehuda says: It does not apply to a fetus, and similarly the fat of a fetus is permitted?
הני מילי גבי טהורה דרחמנא אמר (דברים יד, ו) כל בבהמה תאכלו אבל בטמאה נוהג
The Gemara answers: This statement, that the prohibition of eating the sciatic nerve does not apply to a fetus, is with regard to a kosher species of animal, because the Merciful One stated in the Torah: “And every animal that divides the hoof, and has the hoof wholly cloven in two, and chews the cud, among the animals [babehema], that you may eat” (Deuteronomy 14:6). The term babehema may also be translated as: Inside the animals, indicating that anything inside a kosher animal when it is slaughtered is permitted for consumption, including all parts of a fetus. But with regard to a non-kosher species of animal the prohibition applies.
ומי מצית אמרת דתרוייהו בהדי הדדי קאתו והתנן על אלו טומאות הנזיר מגלח על המת ועל כזית מן המת
The Gemara challenges the assertion that the prohibitions of eating the sciatic nerve and of eating non-kosher meat take effect at the same time. And can you say that they both come into effect at the same time? But didn’t we learn in a mishna (Nazir 49b): A nazirite shaves for having become impure from these following sources of ritual impurity: For having become impure with impurity imparted by a corpse; and for impurity imparted by an olive-bulk of a corpse.
וקשיא לן על כזית מן המת מגלח על המת כולו לא כ"ש וא"ר יוחנן לא נצרכא אלא לנפל שלא נתקשרו אבריו בגידין אלמא איסור טומאה קדים
And this poses a difficulty for us: If a nazirite shaves for becoming impure from an olive-bulk of a corpse, is it not obvious that all the more so he must shave for becoming impure from an entire corpse? And Rabbi Yoḥanan said: It is necessary only with regard to a miscarried fetus whose limbs have not yet become joined to its sinews. Although the fetus does not yet contain an olive-bulk of flesh, since it is a complete entity, it transmits impurity to anything under the same roof. Evidently, the limbs of the body are formed before the nerves and sinews, and therefore the prohibition of eating non-kosher meat takes effect prior to the prohibition of the sciatic nerve.
אע"ג דאיסור טומאה קדים אתי איסור גיד חייל עליה שכן איסורו נוהג בבני נח
The Gemara answers: Even though the prohibition of eating non-kosher meat takes effect prior to the prohibition of eating the sciatic nerve, the prohibition of the sciatic nerve also comes and takes effect upon a non-kosher animal because this prohibition applies to descendants of Noah, i.e., to gentiles. Since the prohibition of eating the sciatic nerve adds an additional stringency that did not exist with regard to non-kosher meat, it takes effect even though there was an already existing prohibition.
דיקא נמי דקתני א"ר יהודה והלא מבני יעקב נאסר גיד הנשה ועדיין בהמה טמאה מותרת להם
According to this answer, the language of the mishna is also precise, as it teaches: Rabbi Yehuda said: Wasn’t the sciatic nerve forbidden for the children of Jacob, as it is written: “Therefore the children of Israel eat not the sciatic nerve” (Genesis 32:33), yet the meat of a non-kosher animal was still permitted to them? This indicates that the basis of Rabbi Yehuda’s opinion is the fact that the sciatic nerve was forbidden to the children of Jacob, who had the status of descendants of Noah.
גופא האוכל גיד הנשה של בהמה טמאה רבי יהודה מחייב שתים
§ The Gemara returns to the matter itself cited above. With regard to one who eats the sciatic nerve of a non-kosher animal, Rabbi Yehuda deems him liable to receive two sets of lashes: One for eating the sciatic nerve and one for eating the meat of a non-kosher animal;