Chullin 111b
חולין קי״א ב — ד"ה אָמַר רַב נַחְמָן
Chullin 111b:4
Explores the interaction of meat and dairy tastes and the status of vessels and foods affected by them, forming part of the Talmudic basis for meat-and-dairy utensil laws.
אָמַר רַב נַחְמָן, אָמַר שְׁמוּאֵל: סַכִּין שֶׁשָּׁחַט בָּהּ, אָסוּר לַחְתּוֹךְ בָּהּ רוֹתֵחַ. צוֹנֵן – אָמְרִי לַהּ בָּעֲיָא הַדָּחָה, וְאָמְרִי לַהּ לָא בָּעֲיָא הַדָּחָה. אָמַר רַב יְהוּדָה אָמַר שְׁמוּאֵל: קְעָרָה שֶׁמָּלַח בָּהּ בָּשָׂר, אָסוּר לֶאֱכוֹל בָּהּ רוֹתֵחַ, וּשְׁמוּאֵל לְטַעְמֵיהּ, דְּאָמַר שְׁמוּאֵל: מָלִיחַ הֲרֵי הוּא כְּרוֹתֵחַ, וְכָבוּשׁ הֲרֵי הוּא כִּמְבוּשָּׁל.
§ Rav Naḥman says that Shmuel says: The knife with which one slaughtered an animal absorbs blood due to its heat, and it is therefore prohibited to cut any boiling food with it, since that food will in turn absorb the blood from the knife. If one cut cold food with this knife, some say that the piece he cut requires rinsing before one may eat it, and some say that it does not require rinsing. § The Gemara cites other statements of Shmuel. Rav Yehuda says that Shmuel says: With regard to a bowl in which meat was salted to remove its blood before cooking, it is prohibited to eat any boiling food placed in it, as that food absorbs blood of the meat from the bowl. And in this Shmuel conforms to his standard line of reasoning, as Shmuel said: A salted food imparts its flavor like a boiling food, and a food item marinated in vinegar, brine, or the like absorbs flavor from the liquid or vessel as would a cooked food.

