Tzohar Rabbi is Incorrect: Lab-Grown Pig Meat is NOT Kosher


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(By Rabbi Yair Hoffman for the Five Towns Jewish Times)

In a recent viral interview with Ynet News and carried by JTA , Rabbi Yuval Cherlow of the Tzohar organization is quoted as saying, “cloned meat produced from a pig shall not be defined as prohibited for consumption – including with milk.”

In the interview, which was given prior to a Bar-Ilan University symposium entitled “Science and Halacha” featuring a talk by the Rabbi, he advocated rabbinic approval of cloned meat “so that people would not starve, to prevent pollution, and to avoid the suffering of animals.”

Rabbi Cherlow further stated that when the “cell of a pig is used and its genetic material is utilized in the production of food, the cell in fact loses its original identity and therefore cannot be defined as forbidden for consumption,” Rabbi Cherlow said. “It wouldn’t even be meat, so you can consume it with dairy.”


It is this author’s opinion that the Rabbi is in error concerning the halacha and that cloned meat produced from a pig would most certainly be forbidden according to all opinions. This is not to say that lab grown meat is a bad idea. Theoretically, if done from a kosher animal that was shechted properly – it could be kosher.


The main reason why cloned meat produced from a pig would be considered forbidden from a halachic point of view is on account of the concept in Halacha known as, “Davar HaMaamid.”  It is discussed in the Yore Deah section of Shulchan Aruch Siman 87.  Essentially, it is an item that establishes and supports the end food product being produced.  This is the same principle that forbids non-kosher cheese – which historically was once started with rennet – a non-kosher product.  Other products considered a Davar HaMaamid are emulsifiers, jelling agents, some enzymes, and solidifying agents.

In order to understand the underlying issue, we need to first explore how lab-produced meat works and then we need to explore the halacha.


Every form of cloning that this author has examined thus far involves the collection of animal cells that have a rapid rate of proliferation. These cells could be anything from embryonic stem cells, adult stem cells, myosatellite cells, myoblasts. Stem cells proliferate fastest but have not yet become a specific kind of cell.  They thus need to be directed as to how they will grow which creates some challenges.  On the other hand fully developed muscle cells are perfect for developing artificial meat, but they do not proliferate rapidly at all.  It seems that the cell of choice are myoblast cells because they do proliferate at a rapid enough speed and the technical challenges of directing how they will grow are manageable.

The next step that is necessary is a growth medium – that is the application of a protein that will foster tissue growth.  This needs to be done in a culture medium in a bio-reactor wherein the cells are supplied with the nutritional and energy requirements that are needed.

The third step that is required is a scaffold so that the meat can grow three dimensionally.  The scaffold should be edible so that the meat would not need to be harvested.  The scaffold should be able to stretch with the growing meat product in order to resemble the taste of regular meat.

Artificially developed meat also requires some sort of preservative such as sodium benzoate in order to protect the product from yeast and fungus.


We are looking at step two here.  What is happening is that the introduction of the growth medium induces the cells to divide.  They will keep on dividing and produce more of the pig cells.  The cells themselves which will make use of the growth medium – are clearly to be considered a Davar HaMaamid.

The Talmud in Avodah Zara 29b cites a question posed by Rabbi Yishmoel to Rabbi Yehoshua as to why cheeses of gentiles were forbidden.  He answered that they establish them with calves of Avodah Zarah.  The Gemorah later (35a) explains that it is as if the prohibition is extant right there.  The Rambam’s explanation of the concept states clearly that even in a thousand it is not batel.

On the other hand, the Gemorah in Chulin 116a seems to indicate that the prohibition is batel in shishim.


There is a debate among the Rishonim as to whether Davar HaMaamid is only forbidden in Shishim or whether it is even in a far greater amount.

The Ri Migash (cited by the Ran in Chullin 35a) and the Rambam (Maachalos Assuros 3:13 and 9:16) both hold that a Davar HaMaamid is not batel even in one thousand.  The Mordechai in Chulin 733 cites numerous opinion that it is not batel even in a thousand.

Tosfos (Chullin 99b), on the other hand, seem to rule that it is only forbidden to the extent of Shishim, but otherwise it would not be forbidden.

The Shulchan Aruch in Hilchos Pesach (442:5) rules like the Rambam as does the Shach in Yore Deah 87:30.


There is another very pertinent halachic debate regarding the parameters of when the laws of Bitul apply.  The Teshuvas HaRashba (Vol. III #214; cited by the Beis Yosef in Yore Deah Siman 134 toward the end “Chometz”)  writes that the notion of something being batel b’shishim is only applicable when it happens by accident.  However, when it is the normal mode of production – the laws of Bittul do not apply.  In other words, we do not always say bitul.  Here it is being done on purpose and it is the normal mode of producing this lab grown pork.

The Nodah BiYehudah (Mahadura Tanina #52) disagrees and rules that we do not limit when the laws of Bitul apply – even if it is the normal mode of production.  What is normative halacha?

Rabbi Dovid Tzvi Hoffman, author of the Melamed L’ho’il writes that we can be lenient and rely upon the Noda BiYehuda only when we first settle in a country.  However, after an infrastructure has developed, we must be stringent in accordance with the ruling of the Rashba.  The Mishna Brurah in the laws of Chanukah (Siman 442) rules stringently in accordance with the Rashba, as does the Mogain Avrohom ibid.


There is no question that the principle of Davar Hamaamid would certainly forbid lab-grown pork.  Normative halacha rules that a Davar Hamaamid is not batel – even in a thousand.  Even according to the view that it is batel, the normative Psak halacha is to follow the ruling of the Rashba – when it is the regular mode of production.

Rabbi Cherlow should retract his statement. While it is noble to be concerned about feeding the masses of people to avoid starvation – that does not mean that we should be declaring that lab-produced pork is kosher.  We can create lab produced cow meat just as easily if we take cells from a just slaughtered cow (Mesachseches). There is also nothing preventing the development of lab grown pork for the gentile world. It is just that there is no need to declare it kosher.

The author can be reached at [email protected]

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  1. Rav Hoffman presents a very convincing set of arguments so it would be interesting if sometime after yom tov, Rav Cherlow or someone from Tzohar would be willing to offer their response, point-by-point….

  2. Cherlow’s statement, coming at this time, is hashgocho pratis – to show the kosher-observing world exactly what it will get if Tzohar starts giving hashgochos – am hoaratzus leading to mass consumption of tarfus.

  3. Even if the product were kosher, mixing it with cheese would obviously be maris ayin. I don’t see Tzohar responding to the halachic question. When they resort to saying stuff like “feeding the masses” (which doesn’t even make sense in this context, by the way) they clearly aren’t concerned in the actual halachic parameters.

  4. 1. It would depend on how the cloning took place. In Rabbi Hoffman’s case, you’re using pig cells themselves. But you could put the genetic material from a pig into a cow cell. Then there’d be no pig cells involved at all.

    2. Even in Rabbi Hoffman’s case, there’d be no maamid if I didn’t eat that one cell that mamesh came from the pig. So if I grow a whole vat of lab pork, and I know that this one corner of the vat had the original cell, I could just avoid eating that part.

  5. With all due respect to Rabbi Hoffman, I am surprised at his supreme level of self-confidence in his own wisdom and in thinking it proper to attack another Rav based on the ENGLISH SUMMARY TRANSLATION of a secular newspaper’s write-up.

    Rabbi Hoffman: Is it possible that Rav Cherlow is not ignorant of the basic principle of davar hama’amid?

    Is it not possible that he addressed this issue in his talk at Bar Ilan, to an audience that included many very serious individuals? Yet, you already know he has to retract?

    Perhaps Rav Hoffman would like to explain how it would be that the Torah journal Techumin (vol 36, I think) had detailed essays by Rav Reizman and Rav Ya’akov Ariel discussing this issue (they disagreed) when everything is so obvious that even a write-up on Yeshiva World News — and votes from its commentators — will settle the whole thing?

  6. Rabbi Hoffman discussed the issue with Poskim. Rabbi Cherlow is seemingly combining three minority opinions to come up with this leniency in order to create “food for the starving.” This is not necessary. Jews do not need to eat pork. Once lab meat is being produced – a kosher type is feasible. Also, this can be pursued to help feed starving people without it being kosher.

  7. With all due respect to Rabbi Hoffman and his self-confidence, I have Techumin 36 in front of me.
    Three essays on the subject.
    The original essay by Rav Reizman was in Techumin 34.
    Aside from what I cited above, there is also one by Rav Veitman, Rav Hamachshir of Tenuva.

    A respectful, serious, halachic discussion.
    Not a one-sided shout-out, as we have here.

    Rabbi Hoffman: Perhaps you would like to contribute to the discussion in Techumin and explain there how you are the only one who has heard of davar hama’amid? — and that there is no answer to the powerful arguments you offer readers of Yeshiva World News?

  8. It’s an interesting question. If you take a cell from a living animal, and cause it to reproduce without being connected to a living animal, what is it from an halachic perspective? What if you take a cell from a plant or from inorganic matter, and through genetic engineering give it the same structure as “meat”, what is its halachic status. What happens when a 3-D printer (a “replicator”) can produce “meat”?

    While there are, I’m sure, some rabbanim who enjoy Star Trek and Doctor Who, one doesn’t answer a “shailoh” based on a science fiction concept. At present the only “cloned” meat comes from a live animal that has been slaughtered, so there is yet to be a real world shailoh. In the future there will probably be a way to make meat without having killed an animal. THEN we should that discussion.

    P.S. Does anyone know of a frum retirement community with a good yeshiva on a planet with low gravity?

  9. I obviously don’t wright the following le’maisa since I’m no posek, but I think that Rabbi Hoffman is going away from the main point.
    “Butul” is shiech when something exists, it’s just in such a small amount that it may be “as if” it wasn’t there.
    The point here is that it’s not only butal, rather, because it changes to such an extent, it’s like it’s not here at all. And doesn’t even have to go thru bitul, something like “nifsal beachilas kelev’” for chumetz.
    The cells are as if it’s a new existence, with no shiechas to the original thing.

  10. and why talk about starvation – the only reason people starve is their government is doing stupid things like having a civil war or sizing farm land from politically incorrect farmers to give it to loyal (but agrculturally inept) supporters. FAMINE is not a problem today. Even in the poorest countries, obesity is the major public health threat. If a rav says something since the person asking him the shailoh said this was to prevent famine, the rav is not to be taken seriously.

  11. I wonder whether Rabbi Hoffman should retract his statement: “Rabbi Cherlow should retract his statement.”

    What right does Rabbi Hoffman have to make a laughing stock of Rabbi Cherlow here, as if Rav Cherlow and the other Rabbonim who have written on this (see the Torah Journal Techumin 34 and 36, among other places) are unaware of basic halacha?

    Why would it not be lashon hora or Motsi shem ra, let alone being mevazeh talmidei chachamim?

    What to’eles could this posting have?
    Does Rav Cherlow read this web site?
    Will genetically engineered pork, with Rav Cherlow’s heksher, be available in the Five Towns or Monsey in the next week or so, to readers of Yeshiva World? (I had thought no such product is commercially viable yet, let alone with a heksher.)

    Rabbi Hoffman, please teach me why I am wrong.

    Thank You!

  12. Shlomo 2, you’re wrong because it’s not lashon hara for one Rabbi to posken differently than another. I’m sorry that you got the impression that that’s how Judaism works. Please contact your local kiruv Rabbi to learn more.

    I thought Rabbi Hoffman was pretty clear, but the comments are showing that people are woefully under educated on the history of kosher cheese. The rennet used to curdle cheese is a) not fit for a dog to eat and b) way less than 1/60th is used in the overall mixture, but for the reason Rabbi Hoffman mentioned, it still assur’s the cheese. Bittul does not apply in that case, as the concern is not about you eating the rennet itself. As for Rebbe Yid’s “avoid eating that part” point, even if the concern of eating the cell were the reason for the issur, which it’s not, since when does kashrus work that way? You think you can have a product that part kosher, part trief and just eat from the kosher side of it?

  13. Shlomo: Unless your entire posts was a troll post pretending to be someone who doesn’t know anything about how the halachic process works, I stand by what I said.

    When Rabbi Heinneman gave a hechsher to the infamous Yom Tov oven, pretty much every single major Orthodox rabbi on the planet told him to retract. Would you like to say that’s also “lashon hara?” The fact that, in this case, there are others that agree with the Tzohar rabbi is irrelevant.

    My guess is that you’re the type that would see even highly-lenient Rabbi as a big goan, and every dissenting machmir rabbi as an out-of-touch, mean-spirited, spreader of lashon hara. Don’t worry, we still do have other posters on this site that are that way too…

  14. B’mechilas kvoid Harav, perhaps “this author” should do a bit more research into the process (beyond the copied Wikipedia text) before calling on “Tzohar Rabbi” to retract his statement.

    1) From what this commenter has read, the growth medium need not involve non-kosher zachin.

    2) Even if the growth medium were non-kosher, there are multiple mediums making it Zeh V’Zeh Gorem.

    3) Finally, it’s not visible to the naked eye, which halacha is generally not machshiv according to most poiskim.

    Being that Davar Hamaamid is d’rabunan (lefi roiv poiskim), lechoireh there’s plenty makoim for Cherlow to be makiel.

    (Agav, L’aniyus dati, Yesh ladoin if this process is bichlal doimeh to Davar HaMaamid. Lechoireh, pshat in Davar HaMaamid is that it’s goirem a shinui in the tevah of the original מאכל. Ma sh’ain kain in our nidoin, the medium isn’t being m’shaneh the מאכל (which doesn’t even exist yet B’tchilah), rather it’s a sibah to be gorem the מאכל to grow. L’choira, it’s more doimeh to feeding an animal, which avada there’s no problem with an animal that eats treif. Oibazoi, the gantzeh shaila doesn’t start.

    Another makoim to say that it’s not mamish Maamid is that the medium isn’t goirmem a niyeh zach, but rather just speeds up the process. Ma sh’ain kain, l’mushul by cheese, it’s the goirem for a zach that wouldn’t have happened otherwise.)

    – Yaakov S.

  15. Neville ChaimBerlin:

    I have no opinion regarding genetically-engineered meat.

    My issue is not that Rabbi Hoffman disagrees with Rabbi Cherlow, but makes it seem that Rav Cherlow is obviously unaware of basic halacha.

    And that is my problem.
    And that is why I wonder as to why it isn’t inappropriate.

    Read the essays I linked to above.
    And read Rav Veitman’s essay in Techumin 36.
    (Rav Veitman is an extremely important voice in worldwide kashrus, to say the least.)
    Note the complexity of the arguments in Techumin 34 and 36 and note that Rav Veitman is unconvinced one way or the other.

    Then get back to us,.