When one cooks many eggs (or small fish) together and only one is forbidden (an egg with a chick/blood, a treif/impure fish): do not take them out one by one while hot, lest the forbidden one remain last without 60 to nullify it → let them cool or pour cold water over them; the great question "do we presume the prohibition remained?" (לא מחזקינן איסורא); and the repulsive creature (זבוב) fallen into the food that one discards without forbidding anything (נ״ט לפגם), plus the rule of the spoon (כף) that took out a forbidden item (Shulchan Aruch, Yoreh De'ah 107 — 2 se'ifim)
הַמְבַשֵּׁל בֵּיצִים הַרְבֵּה בִּקְלִפָּתָן, לֹא יוֹצִיאֵם מֵהַמַּיִם שֶׁנִּתְבַּשְּׁלוּ בָּהֶם עַד שֶׁיִּצְטַנְּנוּ, אוֹ יִתֵּן עֲלֵיהֶם מַיִם צוֹנְנִים לְצַנְּנָם, וְאַחַר כָּךְ יוֹצִיאֵם, מִשּׁוּם דְּחַיְישִׁינַן שֶׁמָּא יִמָּצֵא בְּאַחַת מֵהֶן אֶפְרוֹחַ.
One who cooks many eggs in their shell should not take them out of the water in which they cooked before they cool, or else pour cold water over them to cool them, and only then take them out — because we fear that a chick (אפרוח) may be found in one of them.
Shulchan Aruch, Yoreh De'ah 107:1LEVEL 01
Hebrew text of the 2 se'ifim with a fluent English translation. The order of removing the eggs, the concern of the chick (אפרוח) left last, the repulsive creature (זבוב) one discards and the rule of the spoon (כף) explained with practical cases.
📖 StudyLEVEL 02
In-depth pilpul: the two grounds for the heter (R. Shimshon לא מחזקינן vs R. Baruch בטל ברוב), the egg / fish asymmetry (Taz sk4, Shach sk1), מעמידין הכלי על חזקתו, the status of עירוי (כלי ראשון, siman 105), חקירות and נפקא מינות.
📖 StudyLEVEL 03
Comparative tables (eggs / fish, removed hot or cooled, poured out at once or not), golden rules, classic pitfalls (נשאר באחרונה, לא מחזקינן איסורא, נ״ט לפגם, the כף without חנ״נ for a utensil) and memorization of the 2 se'ifim.
📖 StudyLEVEL 04
The practical halacha according to the Shach, Taz, Pri Megadim and Pitchei Teshuva, then the Sephardic poskim (Yabia Omer, Yalkut Yosef, Or LeTzion) and Ashkenazi poskim. Note: the Shulchan Aruch HaRav does not deal with this siman — this is a level of psak, not "Daat HaRav".
📖 StudyAccording to the Shulchan Aruch (YD 107:1), one who cooks many eggs in their shell should not take them out of the water before they cool, or else pour cold water over them, because we fear that a chick (אפרוח) [forbidden] may be found in one of them. If he took them out hot one by one, the egg containing the chick might remain with the last ones (נשאר באחרונה), and there would no longer be 60 to nullify it, forbidding the food. The remedy: let them cool, or pour everything out at once. For practical halacha, consult your Rav.
This is the heart of the Rama's gloss (se'if 1). According to the stringent view (yesh osrim), if one poured the eggs or small fish into a dish and one of them was found treif or impure, we fear it remained last without 60 and forbid everything. But according to the lenient view (yesh matirin, Beit Yosef in the name of R. Shimshon) — and this is the main ruling — we do not presume the prohibition (לא מחזקינן איסורא) to say it remained in the minority without 60. And even per the stringent view, the utensils are not forbidden, for we keep the utensil on its presumption (חזקה). For practical halacha, consult your Rav.
According to the Shulchan Aruch (se'if 2), a fly (זבוב) and repulsive things that a person's soul recoils from, found in food: one discards them and the food is permitted, since the פליטה of these spoiled things does not forbid (נ״ט לפגם, related to siman 104); such is the widespread custom (though some are stringent). As for the spoon (כף) that took an impure fish out of the pot and was returned to it: one needs 60 against the prohibition only, not against the whole spoon — for we do not say חתיכה נעשית נבילה regarding a utensil; but if there was a little food together with the prohibition on the spoon, one also needs 60 against that little food, which became נבילה. For practical halacha, consult your Rav.