The Kashrut of Laboratory Produced Meat

THE KASHRUT OF LABORATORY PRODUCED MEAT

For confirmed vegetarians, there is no need to justify a change over to a meatless diet.  But even carnivores by choice (those who crave meat) or by default (those whose systems will only thrive with meat in their diets) must admit that the future of meat eating is problematic.  First, meat production is inefficient.  Only parts of the animals raised for food are either eaten or suitable to be eaten.  And as demand grows, more and more animals will need to be raised for their meat.  This, in turn, leads to a second and third problem.  Meat production is unsustainable.[1]  The United Nations calculates that currently 30% of the total land area of the earth is used for the production of meat. According to one estimate, by the year 2050 – when human population is expected to exceed nine billion – nearly 70% of arable land will need to be devoted to meat production.[2]  Crops now intended for human consumption would be diverted to feeding cattle.  And meat production is environmentally damaging.  Raising cattle is responsible for 44% of greenhouse gases, with cows alone responsible for producing 39% of the methane released into the atmosphere.[3]  A complete conversion to cultured meat, however, would result in a 74% – 96% reduction in greenhouse gases compared to the current amount.[4]  Fourthly, the system of meat production widely in use is cruel.  For example, the desire for white veal induces farmers to keep calves in dark and narrow stalls where they are unable to turn around and are fed only milk until they are slaughtered.

 

Pragmatically – let alone morally – the future of meat eating on this planet is wrought with almost insurmountable challenges.  Nevertheless, it would be unrealistic to believe that the mass of humanity that currently remains omnivorous will readily or happily abandon or even limit meat eating en masse.  Hence, scientists have been at work in trying to find a way that will both satisfy the human craving for meat yet concomitantly address the problems of the inefficiency, unsustainability, and environmental harm associated with raising animals for their meat.  These scientists have set out on two different tracks with the one common goal: finding a tasty, economical, and environmentally friendly meat substitute.  One track is intent on making a vegetable-based product.  The other track is working on “growing” actual meat in the laboratory.

 

Champions of the first track, like Stanford University’s Patrick O. Brown,[5] believed that an ersatz meat product would be on supermarket shelves in 2013.  But that year has passed without the expected results.  The European Union has invested millions of dollars in research and development into this track as well.  A company called “LikeMeat” is already in the process of perfecting the techniques for manufacturing a plant-based product that is comprised of combinations of wheat, peas, lupins and soy, with a number of variations possible to accommodate food allergies among consumers.  It comes out of the factory in a long, neutral tasting strip that is textured like chicken but can be colored and flavored to taste like other meats.  A roughly six-foot by twenty-foot device can churn out about 150 pounds of one-centimeter strips of “LikeMeat” per hour at a cost of no more than what a consumer would pay for packaged meat.  Without any traces of real meat, this product will present few, if any, problems, for kashrut-observant consumers.

 

Dutch Dr. Mark Post favors the second track.[6]  His solution to the problems associated with meat production is to grow real meat from an animal’s stem cells.  The technique is fairly simple and based on already tested and operative technology.  Some muscle stem cells are extracted from a donor animal.   They are then put into a laboratory vessel where they are “fed” with an algae soup.  The cells are anchored to a “wall,” like an artificial tendon.  The muscle cells eventually begin to contract on their own but are also electronically stimulated to develop more elasticity and firmness.  When they reach a pre-determined stage in development, the “meat” is removed from the point of attachment and packaged for distribution and sale.  Post estimates that this process could reduce the number of livestock worldwide from ten billion animals to ten thousand animals and never subject any animal to the prospect of slaughter.  Some food futurists, like Josh Schonwald,[7] foresee a time in the near term when consumers will have toaster-size appliances in their homes where they will make their own meat out of virtually any animal from strands of DNA.

 

The first “cultured meat” hamburger was served in August 2013.  It took ten minutes to pan fry but three months to grow, at a cost of  €250,000.   Over the next two years, research has continued and improvements made.  Dr. Post now maintains that the costs of producing cultured meat has been reduced to a much more economical $44 per pound.[8] The “success” of synthetic meat has been widely reported and triggered a range of reactions.

 

While some are fearful of any such product critics call “frankenburgers” or “lab chops,” kosher-observant consumers have other issues on their plates, as it were.  The commandment prohibiting taking “a limb from a living animal” may preclude extraction of animal cells altogether.  Further, the status of meat grown from non-kosher animal cells may be no different than the donor animal and thus prohibited in turn.  And while lab meat can be nourished by algae soup, it can also be nurtured by a bath that includes animal by-products.  These questions must be properly addressed in order to determine the kosher status of laboratory-produced meats.  This article is a further attempt at formulating an answer.[9]

 

The Babylonian and Jerusalem Talmud disagree on the source of the law prohibiting “a limb from a living animal” (ever min ha-chai). Rabbi Yochanan derives the law from the connection of  “life” with “limb” (that is, “flesh”) in Deuteronomy 12:23 – for the blood is the life, and you must not consume the life with the flesh.[10]  But Rabbi Eliezer ben Ya’akov[11] derives the law from Exodus 22:30 that precludes eating flesh torn by the beasts in the field: you must not eat flesh torn by beasts in the fields; you shall cast it to the dogs.  The connection between “torn flesh” and “fields” leads him to conclude that the verse implies that Jews must not cut off and eat flesh from an animal as they may cut off an eat produce of the ground.   Maimonides[12] follows the Babylonian Talmud in this case. Accordingly, Rabbi Nissim Gerundi[13] explains that on Rabbi Yochanan’s view, the Torah holds that since some “limbs” are vital (like the heart or brain), that is, without these body parts the animal could not survive, all “limbs” are called “life” (nefesh).   Nonetheless, any body part removed from a living animal is forbidden to be eaten.  If stem cells were considered to be a body part, their consumption would be a violation of the Torah.

 

Rashi[14] offers a different explanation.  He writes that a “living limb” (ever chai) is one that is irreplaceable.  That is to say, if it is removed, it will not “grow back” (she-einah chozeret).  Thus the text should be read: “Do not eat the life while it still resides in the flesh.”   Rashi excludes from the prohibition against taking a limb from a living animal any part that is replaceable.  If stem cells are such parts, then there is no danger of violating the Torah’s injunction, according to Rashi.  The U.S. National Institute of Health reports that to date, there is no clear evidence that stem cells are replaceable.  While it is true that stem cells have been discovered in a wide variety of adult tissues, they have been found in short supply.  There is no evidence suggesting that stem cells are renewable.  Since the function of stem cells is to repair and replenish damaged or depleted cells of the tissues in which they are found, it would seem that their removal diminishes the ability of the host organism to regenerate and thus limit its life.  So based on current information, even Rashi would consider the extraction of animal stem cells as a violation of taking the limb of a living animal.

 

This analysis is predicated on the premise that microscopic muscle cells are considered to be a body part. If this premise is determined to be false, then the process of extracting muscle cells from a donor animal is not a violation of “taking a limb from a living animal” and may allow for the eating of laboratory grown meat.

 

The trend in Jewish law is to base halachic practice only on what is visible to the naked eye rather than on what is visible when magnified.  Eighteenth century Rabbi Yisrael Lifschitz[15] dismissed the technique of using a microscope to examine the tiny, imperceptible scales of the burbot fish to determine if they fit the criteria of kashrut.  He argued that even though this advance in optical science offered a far better tool for making such determinations than by visual examination, it was inconceivable that the Torah would insist on making a law that could only be observed with visual aids (that would only be available centuries later).  He thus concluded that in the case before him – and in any case where precision was needed – only unaided vision is operative.

 

Similarly, nineteenth century Rabbi Shlomo Kluger[16] dismissed the use of a magnifying glass in inspecting vegetables or grains for insects. He argued that if the Torah requires inspecting certain vegetables or grains before eating them, it is with the understanding that the checking may be done by anyone at any given time. To think otherwise would be absurd. It would result in the same portion of rice would permitted to one person (without a magnifying glass) and prohibited to another (with a magnifying glass). He further argued from an analogy with water.  Scientists have determined that living organisms invisible to the naked eye infest the water we drink.  These organisms would be akin to insects and their ingestion would be prohibited.  Yet no Jewish authority has ever ruled that water should be banned because of the inevitable ingestion of microscopic creatures.  This clearly implies that insects detected in foods with the use of a microscope, which otherwise would not be noticeable, are not prohibited. Rabbi Abraham Danzig[17] and Rabbi Yechiel Michel Epstein[18] echo Rabbi Kluger’s conclusion.   The latter, writing about microscopic creatures visible only through magnification:

The Torah did not prohibit what the eye cannot see for the Torah was not given to angels (i.e. those with superhuman capabilities).  Were this not so, human beings would be unable to ever open their mouths lest they swallow any of the myriad of the smallest creatures that, according to scientists, are in the air.  This would be absurd.  And even if the scientists were proven correct, it would not matter since these creatures are invisible…

 

And contemporary authority Rabbi Shmuel Vosner[19] rules that specks of dirt detected on vegetables by the unaided eye need not be placed under the microscope to determine whether or not the specks are actually insects.  The vegetables may be eaten as is.

 

Likewise, halachic authorities dismiss the need for magnification in examining the spacing between Hebrew words and letters on Torah scrolls or in tefillin and mezuzot[20] or in determining whether the leather “houses” of tefillin are exactly square.[21] While a magnifying glass or microscope might be helpful, legal decisions are made only by what the naked eye can see.

 

While there is a significant dissenter[22] who insists that insects seen under the microscope are forbidden, the trend among halachic authorities is to consider items visible only under magnification as legally irrelevant – even non-existent – and thus ignorable.[23]  This being the case, it would seem that stem cells invisible to the naked eye have no legal reality.  Consequently, their removal from a living donor animal is not a violation against “taking a limb from a living animal.”

 

Further, the extracted stem cells are not eaten.  They merely serve as the source for the production of muscle tissue that is eaten.  And the law against “taking a limb from a living animal” prohibits the eating of the “limb” but not using it for another purpose.  According to the Babylonian Talmud[24] “ever min ha-chai mutar b’hana-ah,” that is to say, one can derive benefit from the limb taken from a living animal.  So even if one were to follow the position of Rabbenu Nissim or Rashi as well as the ruling of Rabbi Jacob Emden against the other major halachic authorities who dismiss as irrelevant anything that is invisible to the naked eye, the fact that Jews would not be eating the removed “limb” but a derivative food would make eating it permissible.

 

Here it should be noted that while the stem cells serve as a source for the production of muscle tissue that is eaten, it would be incorrect to classify the stem cells as a “davar ha-ma’amid.”   As assumed by the Mishnah,[25] a “davar ha-ma’amid” is a catalyst involved in the process of curdling milk for making cheese or in fermenting wine or liquor. According to a fundamental principle of kashrut, a “davar ha-ma’amid” cannot be nullified even when diluted in one thousand times its volume.[26]   So if the stem cells were categorized as “davar ha-ma’amid,” the entire process of producing “meat” in the laboratory would be called into question.  But as noted above, the stem cells are not a catalyst advancing the transformation of a substance into meat.  They are the source out of which “meat” grows.  Thus, if using cheese making as the operative analogy, the stem cells are not the equivalent of the rennet added to the milk to curdle it.  The stem cells are the milk itself.

 

Classifying stem cells as a substance that is not “flesh” at all yields another argument in favor of allowing eating laboratory grown meat.  Jewish law distinguishes between animal flesh and other animal parts in several laws.  Since Scripture (Leviticus 6:20) specifically sets aside as holy anything that touches the flesh of the sin offering, the Rabbis[27] infer that the same rule would not apply to bones, ligaments, horns, or hooves. On this basis, Rabbi Joel Sirkes[28] rules that the ligaments and bones do not count in the measurements of determining whether the minimum amount of flesh was taken from a living animal to conclude that the law was violated.  On Rabbi Sirkes’ view “flesh” is applied narrowly when considering the violation of the law against “taking a limb from a living being.”   Flesh must be actual meat. What may also be deduced from Rabbi Sirkes’s view is that flesh is defined to be meat of sufficient substance to be offered on the altar.  This would clearly not apply to “stem cells.”

 

Supporting this view is that of twelfth century Franco-German Rabbi Jacob ben Meir Tam.  In justifying the local practice of eating honey into which some bees’ legs were mixed he explains[29] by way of an analogy with ass bones.  The Mishnah[30] implies that the rabbis held that unlike its flesh, the bones of an ass are not ritually impure.  The same distinction between “flesh” and “bone” applies to the legs of bees.  If the bones of an ass are not prohibited as part of the flesh of a prohibited animal, than neither should the legs of bees.   Rabbi Yom Tov Lippman Heller[31] explains, in turn, that according to Rabbenu Tam, bees’ legs are “fleshless.”   Or, to use the language of Rabbenu Asher ben Yechiel who concurs with Rabbenu Tam, bees’ legs are “afra b’alma,” mere dust, that is, dietarily irrelevant.  Stem cells would be no different than bees’ legs. [32]

 

Thus far it would seem that the extraction of stem cells from the muscles of a donor animals is not a violation of the law against “taking a limb from a living animal” because items invisible to the naked eye are halachically discountable.  Jewish law functions only on the macro-, not micro-, level. And even if the minority view that takes account of items visible through magnification is accepted, Jewish law does not prohibit deriving benefit from a removed limb.  Thus, growing meat in the laboratory from extracted cells would still be permitted since the cells themselves are not eaten but the meat cultured from them is.   Alternatively, the extracted cells would be permitted because they are not really “meat” at all and only “meat” from a living animal is subject to the prohibition.

 

Hence, there are three separate reasons for permitting laboratory grown meat.  First, Jewish law only takes into consideration items visible to the naked eye.   Since stem cells are not visible to the naked eye, the process of extracting them is not subject to any halachic concerns.  Second, Jewish law does take into consideration items invisible to the naked eye.  Nevertheless, the law distinguishes between taking a limb from a living animal (which is prohibited) and deriving benefit from a limb taken from a living animal (which is permitted).  The meat grown in the laboratory is the product of an industrial process from which we may benefit.  Third, stem cells are not defined as “meat” per se and thus the law of taking flesh from a living animal simply does not apply.

 

According to the first and third reasons, laboratory grown meat is not only permitted, it may not even be classified as “meat” as far as kashrut is concerned.[33]  And this would seem to be independent of the source of the stem cells.  This would imply that “meat” grown in the laboratory from stem cells extracted from, for example, pigs, ostriches, or frogs would be permitted.  And neither would there be any concern regarding admixtures of milk and laboratory-grown meat or waiting times following consumption of laboratory-grown meat before eating dairy.

 

Nevertheless, it would seem to be strange to see Jews eating dairy with “meat” despite the fact that the “meat” was laboratory grown.  Sixteenth century Rabbi Moses Isserles[34] ruled that in order to avoid creating a misimpression that might call a Jew’s good reputation in question (mar’it ayin), if almond milk is served at the table with meat, almond shells should be left beside the milk.  Rabbi Isserles was the first to offer an opinion on dairy substitutes. This opinion later led to some authorities to insist that if a butter or cream substitute is served with a meat meal, the container in which the substitute came must be left on the table as well.  Here, too, some measure need be taken to indicate that the “meat” was not really meat.   However, while there are currently meat substitutes available on the market, like textured soy protein in the form of bacon-like strips or chopped meat, I can find no authority who requires some identifying element on the table to suggest it was not meat at all.   There is no compelling reason to treat laboratory-grown “meat” any differently than meat substitutes.

 

According to the second reason, however, stem cells are still “meat” even though their extraction is not a violation of Jewish law.  This being the case, the rule that “kol ha-yotzei min ha-tamei, tamei”[35] – whatever issues from a forbidden (literally: “ritually unclean”) animal is forbidden – applies.  That is to say, derivative foodstuffs retain the character of its source.   This is why the milk of a forbidden quadruped is forbidden or the eggs of a forbidden species of bird are forbidden.  So although laboratory grown “meat” is permitted, it still retains its identity as ‘meat’ when it comes to the application of other dietary laws.

 

One last factor to consider is the nutrient mixture that “feeds” the growing “meat” cells.  The nutrient mixture may be alga based, posing little or no kashrut problems.  But the nutrient mixture may include animal by-products,[36] presumably from non-kosher sources.  In this case the kashrut status of the laboratory produced “meat” might be compromised.  There are two factors to consider.  First, the process may not involve immersion of the growing cells in a non-kosher “soup” but, rather, only the suffusion of the growing cells with a systematic “shower” of nutrients.  (I have not been able to ascertain the precise details of Dr. Post’s process; one that remains secret.)  How such a “shower” is categorized will determine the extent of the problem.[37]  Second, the principle of “notein ta’am lifgam”[38] may yet apply, nullifying the effects of contact with the forbidden substance on the grounds that the “soup” imparts an unappetizing (literally: defective) taste to the cell mass.

 

The kind of nutrient mixture that bathes the “meat” cells is also evolving.  Professor Amit Gefen of Tel Aviv University is a bioengineer and lead scientist overseeing a yearlong feasibility study launched in April 2015 to determine whether the production of a laboratory cultured chicken breast is commercially viable.  His technique, as reported in the media, also begins with stem cells.  But the growth culture consists of fetal bovine serum: energy rich substrates, amino acids, and inorganic salts extracted from cow uteri.  If his technique proves successful and is adapted to all cultured “meat,” one area of kashrut concern would be eliminated.

 

In sum: there are grounds to consider laboratory grown “meat” as kosher.  Moreover, there are grounds for considering such “meat” as pareve.  And while there is good reason to serve this “meat” in such a way so as to indicate that it is not real meat, there seems to be no requirement to do so.

 

Faced by an emerging, new technology in food, Jews today will sympathize with our ancient ancestors who, when introduced to the remarkable foodstuff known as manna asked: “What is it?” (Exodus 16:15).  Fortunately, we have the guidance of a venerable legal tradition to help answer the question.

 

 

 

 

 

 

 

 

 

[1] cf. Michael Hanlon, The Guardian, “Fake meat: is science fiction on the verge of becoming fact?” June 22, 2012.  The author notes that at present 1600 mammals and birds are slaughtered every second to feed the world’s people.  That adds up to one trillion animals per year.  And as the human population grows, the number of animals slaughtered will only increase.

[2] Ian Sample,”£200K test-tube burger marks milestone in future meat eating,” The Guardian, February 19, 2012.

 

[3] Hanlon, op cit.

[4] Tuomisto, Hanna L. and Texeira de Mattos, M. J., “Environmental Impacts of Cultured Meat Production, Environmental Science and Technology, Volume 45, No. 14, July, 2011, pp. 6117-23.  Scientists at Oxford University and the University of Amsterdam confirmed the analysis.

[5] ibid.

[6] cf. Ian Sample, op cit.

[7] Josh Schonwald, The Taste of Tomorrow: Dispatches From the Future of Food, Harper: New York, 2012.

[8] Next Big Future, May 16, 2015.

[9] cf., for example, Rabbi Yehudah Spitz, “Halachic Insights into Genetically Engineered Meat,” Ohr Somayach International, 2013; Rabbi Daniel Friedman, “Pareve Meat,” Journal of Halacha and Contemporary Society, Vol. LIII, Spring, 2007, pp. 93 – 105.

[10] Sifre, Re’eh 77b; Babylonian Talmud, Chullin 102b.

[11] Jerusalem Talmud, Nazir 6:1.

[12] Mishneh Torah, Laws of Forbidden Foods 5:1.

[13] Chullin 4:797.

[14] Chullin, ad loc.

[15] Tifferet Yisrael, Avodah Zarah 2:7, 3.

[16] Tuv Ta’am va-Da’at, Kuntres Acharon 2:53.

[17] Binat Adam 34.

[18] Aruch Hashulchan, Yoreh De’ah 84:36.

[19] Responsa Shevet HaLevi 7:122.

[20] cf. Rabbi Moshe Sternbuch, Responsa Teshuvot V’Hanhagot 1:628 and 3:323.

[21] cf. Rabbi Moshe Feinstein, Responsa Iggerot Moshe, Yoreh De’ah, Vol. 2, No. 146.

[22] cf. Rabbi Jacob Emden, She’ilat Yavetz 2:124.

[23] cf. Rabbi Zushe Yosef Blech’s article “Peering Through the Insects: The Story of Bagged Lettuce,” published by www.kashrut.com.  Rabbi Blech, author of Kosher Food Production, considers the matter to have been resolved “unequivocally.”  He writes:  “All poskim have concurred that Halachic applications, from cracks in letters of a Sefer Torah to miniature scales on fish to minor blemishes on an etrog.[sic] From a Halachic standpoint, what cannot be seen but someone with average eyesight has no Halachic standing.”

[24] Pesachim 22b.

[25] Orlah 1:7, 8.

[26] cf. Rabbi Moses Isserles, Shulchan Aruch, Yoreh Deah 87:11.

[27] Sifra, ad loc. The rabbis infer the same exclusion from another verse regarding left over sacrificial flesh (Leviticus 7:17; Sifra, ad loc).

[28] Bayyit Chadash on Tur, Yoreh De’ah 62.

[29] Tosafot on Avodah Zarah 69a, s.v. ha-hu.

[30] Yadayim 4:6.

[31] Pilpulei Charifta, Avodah Zarah, 69a, subsection 20.

[32] This conclusion is relevant to assessing the kashrut of laboratory cultured sausages that may include plant or insect proteins that one food technologist called the “lowest barriers to commercialization” since plant and insect proteins are widely available and cheap.

[33] Interestingly, Rabbi Meir Leibush Malbim (Commentary on the Torah, Genesis 18:8) considers meat produced metaphysically (cf. Sanhedrin 59b et al) to be kosher and pareve.

[34] Gloss on Shulchan Aruch, Yoreh De’ah 87:3.

[35] Bechorot 5b ff.

[36] The current culture medium consists of “foetal calf serum” which, Post says, “will change in the final product.”  cf. Sample, op cit.

[37] That is to say, is ‘irui – literally: “pouring” – to be considered tantamount to mixing when applied to mixtures of that which is permitted with that which is prohibited or is ‘irui to be considered sui generis?

[38] cf. Pesachim 44b.