Kashrut 101: Milk and Meat
(יט) רֵאשִׁ֗ית בִּכּוּרֵי֙ אַדְמָ֣תְךָ֔ תָּבִ֕יא בֵּ֖ית יְהֹוָ֣ה אֱלֹהֶ֑יךָ לֹֽא־תְבַשֵּׁ֥ל גְּדִ֖י בַּחֲלֵ֥ב אִמּֽוֹ׃ {פ}
(19) The choice first fruits of your soil you shall bring to the house of your God יהוה. You shall not boil a kid in its mother’s milk.
רֵאשִׁ֗ית בִּכּוּרֵי֙ אַדְמָ֣תְךָ֔ תָּבִ֕יא בֵּ֖ית יְהֹוָ֣ה אֱלֹהֶ֑יךָ לֹא־תְבַשֵּׁ֥ל גְּדִ֖י בַּחֲלֵ֥ב אִמּֽוֹ׃ {פ}
The choice first fruits of your soil you shall bring to the house of your God יהוה. You shall not boil a kid in its mother’s milk.
לֹ֣א תֹאכְל֣וּ כׇל־נְ֠בֵלָ֠ה לַגֵּ֨ר אֲשֶׁר־בִּשְׁעָרֶ֜יךָ תִּתְּנֶ֣נָּה וַאֲכָלָ֗הּ א֤וֹ מָכֹר֙ לְנׇכְרִ֔י כִּ֣י עַ֤ם קָדוֹשׁ֙ אַתָּ֔ה לַיהֹוָ֖ה אֱלֹהֶ֑יךָ לֹֽא־תְבַשֵּׁ֥ל גְּדִ֖י בַּחֲלֵ֥ב אִמּֽוֹ׃ {פ}
You shall not eat anything that has died a natural death; give it to the stranger in your community to eat, or you may sell it to a foreigner. For you are a people consecrated to your God יהוה. You shall not boil a kid in its mother’s milk.

These three passages from Exodus and Deuteronomy repeat the commandment to "not boil a kid in its mother's milk", which is the basis of the second major concern in kosher food preparation: the division between meat and milk.

This is a good example of the distinction that emerges in the Talmud and later Jewish texts between halakah de'oraita (the teaching of Torah) and halakah de'rabanan (the teaching of the Rabbis). The Torah commandment is clear and limited: do not boil a young goat in the milk of its mother. But you may well have questions about the practical implications of this commandment. Read the next passages from the Shulchan Arukh to learn how these texts have been interpreted in practice. The italicised text in these passages is the commentary of Moses Isserleres, which records points at which Ashkenazi practice differs from Sephardi practice.

What has changed from the text of Torah to the practice recorded in the Sulchan Arukh?

באיזו בשר נוהג דין בשר בחלב והיאך נקרא בשול. ובו י"א סעיפים:
כתוב בתורה לא תבשל גדי בחלב אמו ג' פעמים אחד לאיסור בישול ואחד לאיסור אכילה ואחד לאיסור הנאה והוציא אכילה בלשון בישול לומר שאינו אסור מן התורה אלא דרך בישול אבל מדרבנן אסור בכל ענין (כל בשר בחלב שאינו אסור מן התורה מותר בהנאה (טור וארוך כלל ל') .

It is written in the Torah: "you will not cook a kid in the milk of its mother" three times (Exodus 23:19; Exodus 34:26; Deuteronomy 14:21); once for the prohibition of cooking, once for the prohibition of eating, and once for the prohibition of receiving benefit [from the cooked meat and milk products]. The prohibition of eating is presented in the language of cooking, to say that there is no prohibition from the Torah [in regard to meat and milk] unless it is in a manner of cooking, but rabbinically it [the mixture of meat and milk] is forbidden in every way. All meat and milk [mixtures] that are not forbidden from the Torah are permitted to benefit from.

"Benefit from" means that it can be sold, fed to pets, etc.

גדי לאו דוקא דהוא הדין שור שה ועז ולא שנא בחלב אם לא שנא בחלב אחרת אלא שדבר הכתוב בהווה:
[The word] "kid", is not specific, it is the same rule with ox, sheep and goat. There is no difference if it is the milk of the mother, or of another [domesticated] animal. Rather, the verse refers to the common case.
אינו נוהג אלא בבשר בהמה טהורה בחלב בהמה טהורה אבל בשר טהורה בחלב טמאה או בשר טמאה בחלב טהורה מותרי' בבישול ובהנאה ובשר חיה ועוף אפילו בחלב טהורה מותר בבישול ובהנאה ואף באכילה אינו אסור אלא מדרבנן אבל דגים וחגבים אין בהם איסור אפילו מדרבנן: הגה ונהגו לעשות חלב משקדים ומניחים בה בשר עוף הואיל ואינו רק מדרבנן אבל בשר בהמה יש להניח אצל החלב שקדים משום מראית העין כמו שנתבאר לעיל סי' ס"ו לענין דם (ד"ע):
The law only applies with meat from a pure [kosher] animal and milk from a pure animal, but meat of a pure animal in milk that is impure, or meat from an impure animal in pure milk, is permitted to cook and benefit from. Meat of a wild animal and of fowl, even in milk which is pure, is permitted to cook and benefit from; and even eating is only prohibited rabbinically. Fish and grasshoppers are not prohibited [with milk] even rabbinically. RAMA: We make milk from almonds and place bird meat in it, since [milk and bird meat] is only rabbinically [forbidden]. But with meat from a domesticated animal, place almonds next to the milk, so that people don't misunderstand. This is as we said above, in chapter 66.

Maimonides uses this case as an example in his discussion of halakah de'oraita and halakah de'rabanan, to explain the limitations on Rabbinic interpretation. The distinction he is drawing is subtle, but important.

הוֹאִיל וְיֵשׁ לְבֵית דִּין לִגְזֹר וְלֶאֱסֹר דָּבָר הַמֻּתָּר וְיַעֲמֹד אִסּוּרוֹ לְדוֹרוֹת וְכֵן יֵשׁ לָהֶן לְהַתִּיר אִסּוּרֵי תּוֹרָה לְפִי שָׁעָה. מַהוּ זֶה שֶׁהִזְהִירָה תּוֹרָה (דברים יג א) "לֹא תּוֹסִיף עָלָיו וְלֹא תִגְרַע מִמֶּנּוּ". שֶׁלֹּא לְהוֹסִיף עַל דִּבְרֵי תּוֹרָה וְלֹא לִגְרֹעַ מֵהֶן וְלִקְבֹּעַ הַדָּבָר לְעוֹלָם בְּדָבָר שֶׁהוּא מִן הַתּוֹרָה בֵּין בַּתּוֹרָה שֶׁבִּכְתָב בֵּין בַּתּוֹרָה שֶׁבְּעַל פֶּה. כֵּיצַד. הֲרֵי כָּתוּב בַּתּוֹרָה (שמות כג יט) "לֹא תְבַשֵּׁל גְּדִי בַּחֲלֵב אִמּוֹ". מִפִּי הַשְּׁמוּעָה לָמְדוּ שֶׁזֶּה הַכָּתוּב אָסַר לְבַשֵּׁל ולֶאֱכל בָּשָׂר בְּחָלָב. בֵּין בְּשַׂר בְּהֵמָה בֵּין בְּשַׂר חַיָּה. אֲבָל בְּשַׂר הָעוֹף מֻתָּר בְּחָלָב מִן הַתּוֹרָה. אִם יָבוֹא בֵּית דִּין וְיַתִּיר בְּשַׂר חַיָּה בְּחָלָב הֲרֵי זֶה גּוֹרֵעַ. וְאִם יֶאֱסֹר בְּשַׂר הָעוֹף וְיֹאמַר שֶׁהוּא בִּכְלַל הַגְּדִי וְהוּא אָסוּר מִן הַתּוֹרָה הֲרֵי זֶה מוֹסִיף. אֲבָל אִם אָמַר בְּשַׂר הָעוֹף מֻתָּר מִן הַתּוֹרָה וְאָנוּ נֶאֱסֹר אוֹתוֹ וְנוֹדִיעַ לָעָם שֶׁהוּא גְּזֵרָה שֶׁלֹּא יָבוֹא מִן הַדָּבָר חוֹבָה וְיֹאמְרוּ הָעוֹף מֻתָּר מִפְּנֵי שֶׁלֹּא נִתְפָּרֵשׁ כָּךְ הַחַיָּה מֻתֶּרֶת שֶׁהֲרֵי לֹא נִתְפָּרְשָׁה. וְיָבוֹא אַחֵר לוֹמַר אַף בְּשַׂר בְּהֵמָה מֻתֶּרֶת חוּץ מִן הָעֵז. וְיָבוֹא אַחֵר לוֹמַר אַף בְּשַׂר הָעֵז מֻתָּר בַּחֲלֵב פָּרָה אוֹ הַכִּבְשָׂה שֶׁלֹּא נֶאֱמַר אֶלָּא אִמּוֹ שֶׁהִיא מִינוֹ. וְיָבוֹא אַחֵר לוֹמַר אַף בַּחֲלֵב הָעֵז שֶׁאֵינָהּ אִמּוֹ מֻתָּר שֶׁלֹּא נֶאֱמַר אֶלָּא אִמּוֹ. לְפִיכָךְ נֶאֱסֹר כָּל בָּשָׂר בְּחָלָב אֲפִלּוּ בְּשַׂר עוֹף. אֵין זֶה מוֹסִיף אֶלָּא עוֹשֶׂה סְיָג לַתּוֹרָה. וְכֵן כָּל כַּיּוֹצֵא בָּזֶה:

Since the Beit Din [religious court] has the capacity to declare laws and prohibit what is permissible, and its prohibitions last for generations, and similarly they have the capacity to permit that which is prohibited in the Torah for a specific situation. What does this mean that the Torah warns us (Deuteronomy 13:1) “Do not add to it and do not subtract from it”? That one should not add on to what is in the Torah and should not subtract from it, and make that thing set forever as something that is from the Torah, whether the Written Torah or the Oral Torah. How so? It is written in the Torah (Exodus 23:19) “Do not cook a kid in its mother’s milk.” From the interpretation they learn that this verse prohibits the cooking and eating of meat in milk, both the meat of a domesticated animal and the meat of a wild animal, but the meat of fowl is permissible in milk according to the Torah. If the Beit Din came and permitted wild animals in milk, this would be subtracting [from the Torah]. And if it prohibited the meat of fowl and said that it is included in [the wording of] “a kid,” and it is therefore prohibited according to the Torah, this would be adding on [to the Torah]. But if it [the Beit Din] said: “Meat of fowl is permitted from the Torah and we have prohibited it,” and we inform the people that this is a ruling that does not originate from that which is obligatory [in the Torah], they [the people] will say just as fowl is permissible [with milk] since it is not specified [in the Torah], so to [meat of a] wild animal is permissible [with milk] since it is not specified [in the Torah]. And then another will come and say that [meat of a] domesticated animal is permissible [with milk, according to the Torah], except for goat [meat]. And another will come and say that even meat of a goat is permissible with milk of a cow or a sheep, for the verse only says “its mother” who is of the same species [i.e. don’t cook a kid in its mother’s milk]. And another will come and say that even milk of a goat that is not its mother [i.e. the kid’s mother] is permissible [according to the Torah], for it only said “its mother.” Therefore, all meat in milk was prohibited, even meat of fowl. This is not adding to [the Torah] but is creating a fence around the Torah. And similarly anything like this.

In the Guide for the Perplexed, Maimonides is also concerned with this practice, but there his focus is on producing a rational explanation for the Torah commandment. Does this explanation seem consistent with the views Maimonides expressed concerning permitted and forbidden animals? Do you expect it to be widely shared by other commentators?

ואמנם איסור 'בשר בחלב' עם היותו מזון עב מאד בלא ספק ומוליד מלוי רב אין רחוק אצלי שיש בו ריח 'עבודה זרה' אולי כך היו אוכלים בעבודה מעבודותיה או בחג מחגיהם. וממה שמחזק זה אצלי - זכור התורה אותו שני פעמים תחילת מה שציותה עליו עם מצות החג "שלש פעמים בשנה וגו'" כאילו אמר בעת חגכם ובואכם לבית 'יי אלוקיך' לא תבשל מה שתבשל שם על דרך פלוני כמו שהיו הם עושים. זהו הטעם החזק אצלי בענין איסורו - ואמנם לא ראיתי זה כתוב במה שראיתי מספרי הצאבה:
Meat boiled in milk is undoubtedly gross food, and makes overfull; but I think that most probably it is also prohibited because it is somehow connected with idolatry, forming perhaps part of the service, or being used on some festival of the heathen. I find a support for this view in the circumstance that the Law mentions the prohibition twice after the commandment given concerning the festivals "Three times in the year all thy males shall appear before the Lord God" (Exod. 23:17, and 34:73), as if to say, "When you come before me on your festivals, do not seethe your food in the manner as the heathen used to do." This I consider as the best reason for the prohibition: but as far as I have seen the books on Sabean rites, nothing is mentioned of this custom.

Louis Jacobs on Maimonidies

Maimonides (Guide of the Perplexed III:48) understands the dietary laws chiefly as a means of keeping the body healthy. The meat of the forbidden animals, birds, and fishes is unwholesome and indigestible. Maimonides refuses to see the signs for the permitted animals and fishes as anything more than simple indications of the types of animal and fish that are permitted. An animal is not kosher because its chews the cud and has cloven hooves, nor is a fish kosher because it has fins and scales. These are only the means of identifying which species are wholesome and which unwholesome. The prohibition of eating meat cooked in milk is similarly seen by Maimonides to be because such a mixture constitutes gross and very filling food.

Does Louis Jacobs's gloss of Maimonides accurately reflect the original text? Why?

Before continuing, take a moment to think about your favourite foods. Make a list of the meals you most like to eat.

How many of your favourite dishes, or favourite combinations, would need to be adjusted--or be entirely impossible to adjust--to ensure that meat and dairy are not combined in the same meal?

A great deal of Talmud and later commentary is concerned with extremely detailed consideration of how Torah commandments actually work in practice. Read the passages below from Talmud tractate Chullin and from the medieval tractate Issur v’Heter l’Rabbeinu Yerucham. What practical questions do the Rabbis think of as important to consider and discuss? What are the underlying concerns? What remedy for these concerns is proposed in each text?

מתני׳ העוף עולה עם הגבינה על השולחן ואינו נאכל דברי ב"ש וב"ה אומרים לא עולה ולא נאכל א"ר יוסי זו מקולי ב"ש ומחומרי ב"ה
MISHNA: The meat of birds may be placed with cheese on one table but may not be eaten together with it; this is the statement of Beit Shammai. And Beit Hillel say: It may neither be placed on one table nor be eaten with cheese. Rabbi Yosei said: This is one of the disputes involving leniencies of Beit Shammai and stringencies of Beit Hillel.

Beit Hillel and Beit Shammai--the followers of the sages Hillel (the Elder) and Shammai--frequently appear in the Talmud as opponents; typically, Beit Hillel's positions are more lenient, and so it is noteworthy when, as in this case, Shammai is the party with the more permissive position.

BT Shabbat 31a contains a number of anecdotes about the rivalry between Hillel and Shammai; the most frequently cited story can be found here: https://www.sefaria.org/Shabbat.31a.6?lang=bi&with=all&lang2=en

רב יצחק בריה דרב משרשיא איקלע לבי רב אשי אייתו ליה גבינה אכל אייתו ליה בשרא אכל ולא משא ידיה אמרי ליה והא תאני אגרא חמוה דרבי אבא עוף וגבינה נאכלין באפיקורן עוף וגבינה אין בשר וגבינה לא
The Gemara relates: Rav Yitzḥak, son of Rav Mesharshiyya, happened to come to the house of Rav Ashi. They brought him cheese, and he ate it. Next they brought him meat, and he ate it without first washing his hands. The members of Rav Ashi’s household said to him: But didn’t Agra, the father-in-law of Rabbi Abba, teach only that the meat of birds and cheese may be eaten freely? One can infer that with regard to the meat of birds and cheese, yes, one may eat them without washing one’s hands in between, but with regard to the meat of domesticated animals and cheese, no, one may not.
אמר להו הני מילי בליליא אבל ביממא הא חזינא
Rav Yitzḥak said to them: This statement of Agra applies only if one eats them at night, as one cannot see whether some of the food of the previous dish still remains on his hands, and he must therefore wash them. But if one eats by day, I can see that no food remains on his hands, and consequently there is no need to wash them.
תניא בית שמאי אומרים מקנח ובית הלל אומרים מדיח מאי מקנח ומאי מדיח
It is taught in a baraita: Beit Shammai say: Between the consumption of meat and milk one must wipe out his mouth, and Beit Hillel say that he must rinse his mouth. The Gemara asks: What is the meaning of the word: Wipe [mekane’aḥ], and what is the meaning of the word: Rinse [mediaḥ]?
אלא בית שמאי אומרים מקנח ולא בעי מדיח ובית הלל אומרים אף מדיח הוי ליה מקולי בית שמאי ומחומרי בית הלל ולתנייה גבי קולי בית שמאי וחומרי בית הלל
Rather, one must explain the dispute as follows: Beit Shammai say that one wipes his mouth after eating meat and does not need to rinse his mouth as well, and Beit Hillel say that in addition to wiping one must also rinse. This interpretation is difficult as well, since if so, this constitutes one of the disputes between them that involve leniencies of Beit Shammai and stringencies of Beit Hillel, and consequently, let the tanna of tractate Eduyyot teach it alongside the other disputes listed there that involve leniencies of Beit Shammai and stringencies of Beit Hillel.
אלא בית שמאי אומרים מקנח והוא הדין למדיח וב"ה אומרים מדיח והוא הדין למקנח מר אמר חדא ומר אמר חדא ולא פליגי
Rather, one must interpret their statements as follows: Beit Shammai say that one wipes his mouth after eating meat, and the same is true of rinsing, i.e., one must rinse his mouth as well. And Beit Hillel say that one rinses his mouth, and the same is true of wiping. And one Sage said one statement and one Sage said another statement, and they do not disagree.
גופא אמר רבי זירא אין קינוח הפה אלא בפת והני מילי בדחיטי אבל בדשערי לא
§ After citing Rabbi Zeira’s statement tangentially, the Gemara discusses the matter itself. Rabbi Zeira says: Wiping of the mouth can be performed only with bread. The Gemara explains: And this statement applies only to bread prepared from wheat flour. But with regard to bread prepared from barley flour, one may not use it for wiping, as barley bread crumbles in the mouth and does not wipe thoroughly.
ודחיטי נמי לא אמרן אלא בקרירא אבל בחמימא משטר שטרי והני מילי ברכיכא אבל באקושא לא והלכתא בכל מילי הוי קינוח לבר מקמחא תמרי וירקא

The Gemara adds: And even in the case of bread prepared from wheat flour, we said the halakha only with regard to cold bread, but as for warm bread, it is ineffective for wiping even if made of wheat, as it softens and sticks to the palate, and it does not wipe the mouth properly. And furthermore, even if the bread is cold, this statement applies only with regard to soft bread, but one may not wipe with hard bread, as it also does not clean effectively. The Gemara concludes: And the halakha is that the use of all items constitutes effective wiping, except for flour, dates, and vegetables.

(א) אכל בשר אסור לאכול גבינ' עד סעוד' אחר' כר' חסדא (בפרק כ"ה דק"ה) וכן נהג מר עוקבא מפני שהבשר ושומן נדבק בפה זמן ארוך וכ' ר"ב מפני שהבשר שבין השניים קרוי בשר שנא' הבשר עודנו בין שניהם והוא ג' שעות כרש"י ומטעם זה טוב לנקר שינוי בסעודה אחרת אם יאכל גבינה ואם לא אכלו בשר רק כעין טיגון בשומן מותר לאכול גבינה אח"ך בקינוח הפה והדחת ידיו דאינו נדבק מר"ף.

(ב) אכל גבינה ורוצה לאכול בשר יטול ידיו שמא נדבק שמנונית ויקנח פיו בפת או בשאר דברים בר מן קמח תמרי וירקי וידיח פיו במים דבעי קינוח והדחה כך פי' רש"י ור"ח גבי ושוין ב"ש וב"ה שמקנח וכ"ש שמדיח (שם) ור"י היה נוהג לשרות הפת ביין או במים ואוכל במקום קינוח והדחה בפה וריב"א היה מקנח בפת לבדו ומדיחו לבדו שהיה עושה הדחה לידיו ולפיו שהיה בולע מים ומכניס אצבעו לתוך פיו ומדיחו.

(ג) אין אוכלין על שולחן א' בשר וגבינה, ואפי' בשר עוף כב"ה פי' כשאין הפרש ביניהם ונהגו לשים ביניהם קנקן או שאר כלים או ב' מפות א' של בשר וא' של גבינה וכ"כ בתוס' שאנץ.

(ד) ובסמ"ג כ' דנהגו להפסיק בלחם או בקנקן וראיה (לדבר) דמסיק תלמודא (שם דק"ז ע"ב) גבי מכירין זה את זה אסורין דלא אסרו אלא כעין תפיסה א' פי' כשאין הפרש ביניהן.

(1) [If] one ate meat, it is forbidden to eat cheese until [waiting for] another meal. This follows the opinion of Rav Chisda (Perek Kol Habasar, Chullin 105a). This is also the opinion of Mar Ukva since the meat and fat stay in one's mouth a long time, as well as Rabeinu Baruch who says that the meat between the teeth is called meat, as it says: "the meat was still between their teeth" (Bamidbar 11:33). The time is three hours, per Rashi. For this reason it is good to pick one's teeth after the meal if one will be eating cheese. If one did not eat meat, but rather something that was fried in fat, it is acceptable to eat cheese afterwards with wiping the mouth and rinsing the hands. There is no need to inspect the hands. This is from Rabeinu Peretz.

The following passage from the Mishnah explicitly introduces a third category in kashrut: foods that are neither milk nor meat, and therefore may be eaten with either. The technical term for such foods is parve. You can see this category operating above, in the Talmud's discussion of foods that are acceptable for wiping the mouth between meat and milk; this passage adds to the list of parve foods. What types of food are parve? Are there any types of food you're unsure of how to categorise?

(א) כָּל הַבָּשָׂר אָסוּר לְבַשֵּׁל בְּחָלָב, חוּץ מִבְּשַׂר דָּגִים וַחֲגָבִים. וְאָסוּר לְהַעֲלוֹתוֹ עִם הַגְּבִינָה עַל הַשֻּׁלְחָן, חוּץ מִבְּשַׂר דָּגִים וַחֲגָבִים. הַנּוֹדֵר מִן הַבָּשָׂר, מֻתָּר בִּבְשַׂר דָּגִים וַחֲגָבִים. הָעוֹף עוֹלֶה עִם הַגְּבִינָה עַל הַשֻּׁלְחָן וְאֵינוֹ נֶאֱכָל, דִּבְרֵי בֵית שַׁמַּאי. וּבֵית הִלֵּל אוֹמְרִים, לֹא עוֹלֶה וְלֹא נֶאֱכָל. אָמַר רַבִּי יוֹסֵי, זוֹ מִקֻּלֵּי בֵית שַׁמַּאי וּמֵחֻמְרֵי בֵית הִלֵּל. בְּאֵיזֶה שֻׁלְחָן אָמְרוּ, בַּשֻּׁלְחָן שֶׁאוֹכֵל עָלָיו. אֲבָל בַּשֻּׁלְחָן שֶׁסּוֹדֵר עָלָיו אֶת הַתַּבְשִׁיל, נוֹתֵן זֶה בְצַד זֶה וְאֵינוֹ חוֹשֵׁשׁ:

(1) All meat is forbidden to cook with milk, except for the meat of fish and locusts. And it is forbidden to place it with cheese on the table, except for the meat of fish and locusts. One who vows [to abstain] from meat, is permitted to [eat] fish and locusts. "A bird may go on with cheese on the table, but is not eaten," in the words of Beit Shammai. And Beit Hillel says, "It does not go and it is not eaten." Said Rabbi Yose, "This is [one] of the lenient rulings of Beit Shammai and stringent rulings of Beit Hillel." About which table were they speaking? About a table on which one eats. But for a table where one sets dishes on it, one puts this next to this and does not worry.

There is one area of food preparation in which the combination of meat and milk is particularly important, and difficult to avoid, and that is the preparation of cheese, which is produced by the reaction of milk to a substance called rennet, an enzyme found in a cow's stomach (although there are other, non-animal based sources for rennet, as well, which is why some cheeses are suitable for vegetarians and some are not).

חלב הנמצא בקיבה אינו חלב ומותר לבשל בו בשר אפילו בצלול שבה (טור בשם רי"ף ורמב"ם) ויש מי שאוסר (תוס' ורא"ש ור"ת ורשב"א ור"ן) (וכן נוהגין):
Milk that was found in the stomach [of the animal] is not called milk, and it is permitted to cook meat in it, even in the liquidy part. And there are those that forbid it, and so is our custom.
חלב הנמצא בקיבה (לכתחלה אין להניחו בקיבה עד שיצטנן החלב בתוך הקיבה (ארוך כלל י"ח בשם רבי שמחה והג"ה אשיר"י) אבל בדיעבד אין לחוש עד) שנמלח בקיבתה או שעמד בו יום אחד (ואז) אסור להעמיד בו: הגה ואם העמיד בו אם הוא הצלול אוסר כל הגבינות עד שיהא ס' בחלב שהעמיד נגד הקיבה האסורה ואם היה ס' בחלב הכל מותר ואם היה הקיבה קרושה אינה אוסרת כלום אפי' לא היה ס' בחלב נגד הקיבה (לדעת ר"ת) ואם היה הקיבה צלול מתחילה ונקרש יש לו דין צלול (בית יוסף בשם רשב"א ובשם הפוסקים) ויש מקילין בזה (ש"ד ובית יוסף בשם המרדכי) ובמקום הפסד יש להקל עור הקיבה לפעמים מולחים אותו ומייבשין אותו ונעשה כעץ וממלאים אותו חלב מותר דמאחר שנתייבש הוי כעץ בעלמא ואין בו לחלוחית בשר (ב"י בשם שבולי לקט):
Milk that was found in the stomach [of the animal] from the outset one should not leave it in the stomach until the milk that's in the stomach cools off, but after the fact, there is nothing to worry about until it was salted in the stomach, or it stood in it for a full day, [then] it is forbidden to curdle milk with it. RAMA: And if one did curdle milk with it, if it was liquidy, the entire cheese is forbidden unless there was sixty times the amount of [permitted] milk that one made curdled with against the forbidden [milk] from the stomach. And if there was sixty times the milk it is all permitted. And if the [milk in] the stomach was solidified, it does not forbid [the cheese] at all even if there wasn't sixty times the [permitted] milk against the [milk in] the stomach. And if the [milk in] the stomach was liquidy at first and became solidified, it has the law of liquidy [milk]. And there are those that are lenient in this matter, and in a case of monetary loss, there is room to be lenient. The skin of the stomach, sometimes they salt it and dry it out and it becomes like wood and they fill it with milk, [in this case the milk is] permitted, since after it was dried out it is like mere wood, and it has no moisture of the meat in it.
אם העמיד גבינה בעור קיבת כשרה יש בה טעם בשר אסורה ואם לאו מותרת אבל המעמיד בעור קיבת נבילה וטריפה ובהמה טמאה אוסר בכל שהוא: הגה משום דדבר האסור בעצמו ומעמיד אפילו באלף לא בטיל (כ"כ ב"י לדעת הרשב"א ור"ן) ודוקא שלא היה שם מעמיד אחר רק האסור אבל אם היה שם ג"כ מעמיד היתר הוי זה וזה גורם ומותר אם איכא ס' נגד האסור (ממשמעות המרדכי) .
If one curdled cheese in the skin of the kosher stomach, if there is the taste of meat in it, it is forbidden, and if not, it is permitted. But if one curdled in the skin of the stomach of an invalidly slaughtered animal or an invalid animal or a non-kosher animal, it is forbidden with any amount. RAMA: Because something that's intrinsically forbidden, and one [used it] to curdle milk, even in a thousand parts it's not nullified. And this is precisely if there was nothing else that was used to curdle except the forbidden item, but if there was something else that is permitted that was used to curdle, then both this and that caused it [to curdle] and it would be permitted if there was sixty times [the permitted] against the forbidden.

60:1 (calculated by volume) is the standard ratio of kosher to non-kosher food that most Rabbis accept as being sufficient to ensure that there is no taste of treyf or an unacceptable mixture of flavours.

What concerns are being addressed by the 60:1 ratio? What other concerns does the Shulchan Aruch suggest be taken into account when determining the kashrut status of a cheese? What concerns are still considered important in the modern discussion on kosher cheese below, and what is the reasoning for the difference between the two texts?

Kosher Cheese

The controversy over the kashrut of cheeses is an old one, dating back to the time of the Talmud (Mishnah Avodah Zarah 2:4-5, Mishnah Chullin 8:5, Chullin 116b). Cheese is made from curdled milk. Since the curdling agent was rennet, which is extracted from the walls of a calf’s stomach, cheese was forbidden as a mixture of dairy and meat. According to some authorities, however, the use of rennet does not affect the kashrut of cheese because rennet no longer has the status of food and instead is comparable to a mere secretion (pirsha b’alma). This controversy appears again and again among the poskim (see Rabbenu Tam in Avodah Zarah 35a, s.v. חדא קתני; Maimonides Hil. Ma’akhalot ‘Asurot 4:13, 14, 19; ‘Aruch Hashulchan Y.D. 87:42). Some halachic authorities demand a hechsher for certain cheeses, implying that those without a hechsher are not kosher; other authorities maintain that all cheeses are permissible and no hechsher is necessary.

The Committee on Law and Jewish Standards of the Rabbinical Assembly has decided to follow the lenient opinion. First of all, it reasons, the chashashot, fears expressed by those who require a hechsher applied only in former times, when cheesemaking was a cottage industry and there was no way to control the ingredients used. Under these conditions, there was always the danger that an individual farmer who made cheese might use the milk of a non-kosher animal or might add lard to the mixture. Today however, at least in America, cheesemaking is a major industrial enterprise regulated by the Pure Food and Drug Law, which requires that most food products bear a label listing their ingredients.

Furthermore, the rennet used in many of the hard cheeses does not impair their kashrut, both for the Talmudic reason stated above and also because the substance from which the rennet is extracted is thoroughly dried and treated with strong chemicals, and this process makes the rennet a D’var Chadash (new substance) or comparable to a piece of wood (eitz b’alma). Thus, all cheeses that are subject to the Pure Food and Drug Act should be considered kosher.

- Rabbi Isaac Klein

The separation between milk and meat also influences the treatment of cooking utensils. The following passages discuss the practicalities that arise from this; pay careful attention to the way that the concerns of kashrut evolve over time. What role does changing technology play in the way that the text of Torah is interpreted?

קדירה שבשל בה בשר לא יבשל בה חלב [בישל בה <בשר> חולין לא יבשל בה תרומה] תרומה לא יבשל בה חולין ואם בשלן ה"ז בנותן טעם.

A pot in which meat was cooked may not be used to cook milk. If consecrated meat was cooked in it, it may not be used to cook non-consecrated meat. And if it was used, it all goes by the giving of flavour.

(א) קדירה שבשלו בה בשר לא יבשלו בה חלב. ובו סעיף אחד:

קדירה שבשל בה בשר לא יבשל בה חלב ואם בישל בה בתוך מעת לעת אסור בנותן טעם (וצריך לשער נגד כל הקדירה) אבל אם שהה מעת לעת קודם שבישל בה הוי ליה נותן טעם לפגם ומותר התבשיל אבל הקדרה אסורה לבשל בה לא בשר ולא חלב:...

(1) A pot in which meat was cooked, one may not cook in it milk. And if one cooked [milk] in it within 24 hours, it is forbidden on account of “giving taste.” And one needs to measure [for negation by 60] against the entire pot. But if it sat for 24 hours before one cooked in it, [it is a case of] “giving detrimental taste,” and the food [cooked in it] is permitted, but the pot is forbidden to cook in either meat or dairy...

דין מאכל חריף שנחתך בסכין של בשר. ובו ה' סעיפים:
צנון או סילקא שחתכם בסכין של בשר בן יומו או שאינו מקונח אסור לאכלם בחלב עד שיטול ממקום החתך כדי נטילת מקום שהוא כעובי אצבע או שיטעמנו ולא יהא בו טעם בשר שאז מותר בהדחה ויש אומרים דהוא הדין לאינו בן יומו והוא מקונח. ...

1) Radish or beets that were cut with a meat knife, used that day or that was not cleaned off are not allowed to be eaten with dairy, until a slice is removed from the location of the cutting that is an "amount to be taken." This amount is equivalent to the width of a thumb. Or let it be tasted, and if it does not have the taste of meat it can be eaten with dairy with mere rinsing. There are those who say that this is also the rule with a knife that was not used that day and was cleaned off. ...

Blu Greenberg, How to Run a Traditional Jewish Household

Laws of Kashrut require total separation of meat and milk products. This means not only separating foods in cooking and eating, but separating everything that is used in the process: a completely separate set of dishes, flatware, knives, pots, pans—one for meat and another for dairy. It’s like outfitting two separate kitchens.
Jews who keep kosher often have six sets of dishes, none of which are there just for show: an everyday set of meat, an everyday set of dairy, a good set of meat, a good set of dairy, a set of dairy Passover, a set of meat Passover. That’s a lot of cupboard space.


Where it is possible, a kosher kitchen will contain two sinks: one for meat and one for dairy. Where there is only one sink, the dishes are never put directly into the sink. Instead, separate racks are used for meat or dairy, likewise, separate sponges, scouring pads, dish towels, counter drain racks, and so forth. For convenience, everything is color-coded—for example, red for meat, blue for dairy. Counters made of Formica can be used for meat or dairy as long as the food is cold and the counter is perfectly clean. However, many Jewish housewives set aside special counter sections for meat or dairy.

Stove burners can be used for either meat or dairy, as can an oven. However, meat and dairy foods should not be cooked simultaneously in an oven. Refrigerators, where everything is cold, can be used to store both meat and dairy as long as the foods are sealed and are kept separate; one would not stack, say, a salami on top of a container of butter.

Dishwashers are an interesting story, part of the “politics” of kashrut. Depending on which rabbi one asks, dishwashers may or may not be used consecutively for meat and dairy. If the interior basin is metal, some rabbis will say the dishwasher can be used for meat and dairy (consecutively), as long as it is cleaned by running a full cycle before each use. Most require that different racks be used. For a decade now, individual Israeli rabbis have ruled that not only metal-interior dishwashers but porcelain enamel ones as well may be used for meat and for dairy if there has been an interim cleaning cycle and a change of racks. However, one is required to ask a rabbi. And having asked, one must abide by his decision.

YOREH DEAH 95 2015 On the Kashrut of Dishwashers by Rabbi Loel M. Weiss

1. Dishwashers made for residential use, whether metal or plastic may be kashered from treife to kosher and from hametz to Passover. The procedure is as follows: The dishwasher should be thoroughly cleaned paying special attention to the filter and the silverware rack. The dishwasher should not be used for 24 hours. The dishwasher should be run one time at the highest temperature with soap in the soap dispenser and in the main dishwasher.

2. The dishwasher may be used to wash meat and dairy dishes consecutively. While we do not require new racks, we do require waiting 24 hours between using the dishwasher for meat and dairy dishes. However, if for some reason the dishwasher was used without the 24 hour waiting period, then b’dieved, we can rely on the soap rendering the taam pagum and the dishes are still kosher. It is strongly suggested that if there is a filter that requires manual cleaning at the bottom of the dishwasher, it be checked to assure there are no pieces of food remaining at the bottom. Also, the silverware rack must also be checked for food residue.

3. Dishwashers may not be used to wash dairy and meat dishes simultaneously.

Ask the Expert: Kashrut in Shtetls

When I asked Prof. Kraemer about the history of two sets of dishes in the home, he reminded me that I was making assumptions about what “sets of dishes” means. The kinds of utensils we use for eating have changed over time, so while now we may be accustomed to having dinner plates, salad plates, bowls, mugs, glasses, plus a knife, a fork, and a spoon at minimum, this wouldn’t necessarily have been the norm in earlier eras. “In order to have separate dishes, you need to have dishes in the first place,” Kraemer said. For hundreds of years, Jews ate from large bowls and platters shared by the whole family, instead of individual plates. This necessitated far fewer objects in the kitchen, and meant that having duplicates of everything for meat and milk was less of a hassle. This lasted until about the 17th century, when eating technologies began to evolve towards individual portions and plates.

According to Prof. Kraemer, by the time shtetl life was in its heyday, in the 18th-19th centuries, personal flatplates, spoons, knives, and often forks had become the convention, much like what we have today. In observant Jewish communities (both shtetls and urban communities) the norm was to have two sets of dishes, one for meat, and one for dairy.