After two decades of deliberation, the USA's Food and Drug Administration has approved the first ever genetically engineered food animal, a fast-growing Atlantic Salmon called AquAdvantage salmon.

According the agency, which announced the approval Thursday, the modified salmon are safe to eat, equally nutritious as other salmon, and should pose no threat to the environment.

First created in 1989 and submitted to the agency for approval in 1995, the Atlantic salmon are modified to carry a growth hormone gene from Chinook salmon. That gene is further engineered to be under the control of a tiny bit of DNA, called a promoter, from the eel-like ocean pout fish. In general, DNA promoters are non-coding sequences that help control the expression level of a gene—how much protein product is synthesized from the gene. With the engineered promoter boosting hormone production, the modified salmon grow to market-size in about half the time of conventional Atlantic salmon.

["FDA approves first GM food animal—Atlantic salmon," by Beth Mole, ars technica, Nov 19, 2015]

Atlantic and Chinook salmon are kosher, but ocean pout is not kosher.[Source]

Is AquAdvantage salmon kosher?


4 Answers 4


Kosher speciation

Generally speaking, we have a rule that "kol hayotzei min hatahor tahor, vichol hayotzei min hatamei tamei" ("that which comes from a kosher species is kosher, and that which comes from a non-kosher species is non-kosher"; see Bekhoroth 1:2). Since this new species comes from kosher and non-kosher species, there would be several potential halachic arguments that might be raised.


Would we consider it a taaroveth (mixture) of kosher and non-kosher? If that were the case, we would presumably be able to apply the rule of bittul b'rov/b'shishim/b'elef (annulment in a majority/1:60/1:1,000) inasmuch as the majority of the tissue come from kosher sources.

However, it's at best controversial whether a living organism could be considered a full-fledged ta'aroveth. While we are indeed strict with regard to animals that have been entirely sustained/fed with non-kosher (see e.g. Rama Yoreh De'ah 60:1), animals that even have been primarily fed non-kosher would not seem to be a problem. If genetic engineering is considered no more significant than feeding, it shouldn't be a problem.

Davar hama'amid

One potential caveat to this reasoning is presented by the principle of davar hamaamid (see e.g. Rambam Ma'achaloth Assuroth 9:16), since the non-kosher tissue/gene causes the animal's dramatic growth-rate. A counterpoint to this line of argument would be that the actual non-kosher tissue that is added is presumably smaller than what could be discerned by the naked eye which may well remove from it any halachic significance (though this reasoning itself potentially opens up a Pandora's box of questioning...). Further, an animal fed primarily but not exclusively non-kosher is also arguably no worse in this respect.

Finally, from a recent New York Times article on the topic:

All that being said, when we return to the question of the genetically engineered salmon, Rabbi Menachem Genack, the chief executive of the Orthodox Union’s Kosher Division, believes that the genetically engineered salmon would probably be kosher even if some of its genetic material came from trayf. “If this is a salmon that has fins and easily removable scales,” Rabbi Genack told me, “that is what’s critical.”

  • 1
    The directly comparable case that could have been contemplated already would be cross-breeding a kosher animal with a non-kosher one, but I wonder if that's even theoretically possible. Maybe there are birds that are capable of cross-breeding that we have a tradition of one's being kosher, but not for the other.
    – Isaac Moses
    Commented Nov 23, 2015 at 19:02
  • @IsaacMoses I believe the gemara explicitly states that only kosher species can successfully breed with kosher species (at least with regard to animals). This is one of the arguments to post-facto justify the consumption of turkey since there have been some attempts to create e.g. chicken turkey hybrids with some limited success. I believe Ari Zivotofsky has a thorough article on it.
    – Loewian
    Commented Nov 23, 2015 at 19:03
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    @IsaacMoses Though of course it's only a matter of time before a genetically-engineered cud-chewing pig mates with a traditional, treif one...;)
    – Loewian
    Commented Nov 23, 2015 at 19:09
  • @Loewian: the attempts to breed chicken-turkey hybrids do not seem to have been particularly successful: student.societyforscience.org/article/churk-not-thanksgiving - perhaps it is not meant to be
    – Henry
    Commented Nov 23, 2015 at 22:03

I'd asked Rabbi Hershel Welcher of Queens a similar question, about goats that were given a bit of spider genes so they would produce gossamer in their milk. He felt the concept of "zeh v'zeh gorem, mutar" applied -- as the spider genes would not have sufficed to produce an organism, such a goat is kosher.

So the same should apply here.


The Chasam Sofer (Toras Moshe parshas Shemini) writes that the meaning of the Medrash (cited by many Rishonim) that the pig is called a חזיר because עתיד הקב"ה להחזירה לישראל - Hashem is going to "return" it to the Jewish people - is that the physiology of the pig will be altered to chew its cud (the Kosher sign that it currently does not have) and will therefore be Kosher. The Chofetz Chaim said, based thereon, that the Kosher signs are actually the cause of an animal being Kosher or non-Kosher - the same pig, upon being given the second Kosher sign, will become Kosher.

That being the case, if this fish has fins and scales, then it is Kosher.

I was present when R' Heinemann was asked on point about AquAdvantage salmon, and he said that it is Kosher for this reason. (He specifically based it on the verse about fish - כל אשר לו סנפיר וקשקשת במים בימים ובנחלים אותם תאכלו - anything which has fins and scales in the water, seas, and streams you may eat. If it has fins and scales, bon appetite.)


This fish is an abomination, and there are many examples in the Talmudic discourse to prove that it is not acceptable to cross-breed a kosher, and non-kosher animal. This is not a result of two kosher animals, but a Kosher and a non-kosher animal. This is completely unacceptable for a Jew, and it is an abomination. Furthermore, Jews are commanded to be HOLY, and to not follow the ways of the Goyim. Eating this is following their ways.

  • 1
    Welcome to MiYodeya Hadassa and thanks for this first answer. Can I recommend you take the tour to get a sense of how the site works? Also note MiYodeya is putting significant emphasis on sources since we don't know you. Your answer would be stronger with a source that genetic material added from a non-kosher source makes an animal non-kosher since it goes against accepted halacha that kosher simanim is how one decides if animal is kosher. Great to have you learn with us!
    – mbloch
    Commented Oct 3, 2019 at 2:12

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