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The Crown of Halacha

Gevinas Yisroel vs. Gevinas Akum: The Making of Kosher Cheese I

This entry is part 2 of 12 in the series Rav Bloomenstiel

By Rav Avraham Chaim Bloomenstiel, shlit”a


I have been asked a few times: “Why does cheese need a hekhsher?” In response, I usually ask, especially if the inquirer is well-versed in the kosher lifestyle, what their hava amina is that cheese doesn’t need a hek hsher!? The reply is invariably a combination of or variation on these three ideas:

1) We in the US can rely on federal supervision of milk to ensure that our kosher milk has not been vitiated with tamei milk. This concept stems from the famous heter of Rav Moshe Feinstien in his Igros Moshe[1]. As well, kol she-ken, we don’t assume that cheese-producers mixed in tamei milk because the presence of tamei milk would negatively affect the finished product.[2]

2) The ingredients in cheese are essentially kosher.

3) Rennin, also called rennet or chymosin[3], is an animal-derived enzyme used to solidify cheese. In the US and Great Britain, however, rennin isn’t such a problem since most curdling agents are from synthetic or vegetable sources.

 While each of these points contains some truth, they also share some common misunderstandings. The main problems are as follows:

1) Mixing milks – The confusion here is between the gezeiros of chalav akum and gevinas akum. In clarifying these decrees, the Rambam writes (Ma’akhalos Assuros 3:12-13):

12. The milk of an impure animal will not curdle and solidify like the milk of a kosher animal. Should tamei milk be mixed with kosher milk and then curdled, the kosher milk will curdle and the tamei milk will come out with the whey. 13. On account of this, the law is that any milk found in the possession of a non-Jew is prohibited lest he mixed in tamei milk. The cheese of non-Jews should be permitted since tamei milk will not become cheese. However, in the time of the mishnaic sages they decreed an issur upon non-Jewish cheese because non-Jews use the stomach tissue of an animal they slaughtered [as a solidifying agent], which is forbidden as neveilah.

We see that mixing milks, while the reason for chalav Yisrael, is not the reason for gevinas akum[4]. Knowing this, we see that Rav Moshe’s heter is unrelated to our question, as is the kol she-ken based upon it.

2) Ingredients – The essential ingredients in US produced cheeses are kosher. However, many of the peripheral additives pose serious problems. These substances are often omitted from the list of ingredients on the product label. One such additive is lipase. This flavor-enhancing enzyme is added in the manufacture of strong, aged cheeses such as Romano and Parmesan. Most lipases used today are produced from the tissues of tame or neveila animals.   Yet, even if all the ingredients and equipment were kosher, the cheese may still be ossur due to the decree of gevinas akum.

3) Rennin – Rennin lies at the heart of the gevinas akum gezeira. In the past, rennin was derived from the tissue or semi-digested substance in the stomach of a non-kosher animal. Any cheese made from this rennin would, therefore, also be non-kosher. The sages prohibited non-Jewish cheese for concern that it was produced with this material. Since most of today’s American and British produced cheeses are made with synthetic rennet, perhaps this decree shouldn’t apply in their countries? Unlike the two previous hava aminas, this one presents a real question.

Notice that gevinas akum shows up in all three of the above hava-aminas. Often confusing and easily misunderstood, gevinas akum creates come difficult issues in modern dairy hasgacho. The tannaim anticipated this halakha’s potential for confusion, hiding their reason behind it for an entire year after its proclamation.[5] Their worry was that, should they reveal the reason for the ruling, the populace would misinterpret the decree and come to treat it lightly.

The Metzius

Before going further, let us look at some basic components of cheese making:

Milk – Milk is composed of water, fat, sugar (lactose), and proteins. The two most important proteins for making cheese are casein and whey.

Hard vs. Soft cheese – These two main categories of cheese have different methods of production:

Hard cheese – Hard cheeses are made in two basic stages. First the milk is soured and cured to develop the desired flavor. In the second stage, the milk is curdled by adding rennin. The resulting curds are then shaped, molded, dried, and aged into cheese. These cheeses are known as “rennet-set cheeses.”

Soft cheese – The manufacture of soft cheeses relies on a natural property of casein to curdle the cheese. Casein is only stable at a pH above 4.6. If the pH falls below this, the casein breaks down, forms curds, and ends up as ricotta cheese, cream cheese, etc. Traditionally, a cheese maker would let the cheese self-acidify by setting milk out to ferment (sour). As the natural bacteria in the milk work their wonders they produce lactic acid. Eventually the pH falls below 4.6 and the milk curdles. Today, the process is hastened by adding phosphoric acid or other chemicals to lower the pH.

Rennin – Above it was mentioned that rennin was used to hasten the curdling of hard cheeses. Rennin is a protease, an enzyme that splits proteins into their constituent peptides (smaller units made of amino acids). When added to cheese, rennin bonds to and breaks down casein into peptides forming a molecular matrix that entraps fat, whey, minerals, and other elements. This matrix becomes the curds that precipitate out from the milk.   In the past rennin was derived from either the stomach tissue of the abomasum (the ‘or ha-kaiva) of ruminants, or from the milk found within the abomasum (kaiva).   Genetically engineered microbial rennet and vegetable rennin have almost totally replaced animal-source rennet in the US industry. Microbial rennin is also becoming standard in Great Britain. The important fact for us, however, is that rennet is not essential for the production of soft cheeses. This is not to suggest that rennet is not used. Many factories add a small amount of rennet (less than 1.7 ml per 1000 lbs liquid milk) to increase control and consistency in the process.

 To summarize: Hard cheese production needs a curdling agent. Soft cheese production needs acidity. We will return to this idea later.

Gevinas Akum in the Gemora

As mentioned above, the Mishnaic sages hid the rationale for gevinas akum for one year. By the time of the Amoraim the origins of the rule had become a matter of dispute. The Gemora (A.Z. 35a-b) attempts to reconstruct the intent of the sages by offering several opinions for why the decree was made. The propositions include:

R’ Shimon ben Pazi in the name of R’ Yehoshua ben Levi – The gemora on 30a-b introduced the prohibition of gilui – beverages left uncovered and unsupervised. The concern is that snakes may have deposited venom into these liquids. Non-Jews are not careful about keeping milk covered.   As Tosefos[6] explains, the gentiles were careful to cover their drinking water, but not milk. Though the water of gentiles is permitted, their milk is ossur d’rabbanon on account of sakana- According to Rashi‘s reading of this Gemora, R’ Shimon ben Pazi is refuted by R’ Yirmiyah.

R’ Shmuel – Non-Jews make their cheese with neveilah The Gemara does not reject this reason.

R’ Malkiya in the name of Rav Adda bar Ahavah – they coat the surface of the cheese with lard[7]. The Maggid Mishna[8] writes that the coating discussed here was a very thin smearing that would be batel under normal circumstances. Since the cheese is ossur despite the apparent bitul of the fat, he makes a curious observation: the taste of issur is irrelevant to ossuring the food of an akum.

Rav Chisda – they curdle the cheese with vinegar that is a by-product of yayin nesekh. The gemora questions why the cheese is only prohibited for eating. If the issur is due to yayin nesekh, then shouldn’t the cheese be prohibited for benefit as well?

In the next part of this series (posted next week) we will look at the Rishonim, Acharonim,  and halacha le-maaseh today…


[1] Igros Moshe Y.D. 47, 48, 49. See also Rav Henkin 2:57. The Chazon Ish 41:4 also writes on this issue, but there are some difficulties in understanding his position.  

[2] This is brought in Tos. A.Z. 35a, d.h. Lefi, and is also a hava amina to matir chalav akum cited by the Rambam, M.A. 3:13.

[3] Some food scientists consider these terms interchangeable. Others define “rennin” and “chymosin” as referring to a pure enzyme while “rennet” refers specifically to rennin/chymosin extracted from an animal’s stomach. In this writing the terms are used interchangeably.

[4] It seems as if R’ Chanina suggests vitiated milk as the reason for gevinas akum (A.Z. 35a). This is difficult to understand, even though the Tur cites R’ Chanina as a possible explanation of the decree. See Rashi, d.h. Lefi she-i-efshar; Tosafos ibid. d.h. Lefi; and Tosafos ha-Rid in defense of Rashi.  

[5] Avodah Zarah 35a.

[6] ibid. 35a, d.h. Mishum.

[7] Pig fat, specifically. See Tur 115.

[8] Ma’akhlos Assuros 3:13.

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