OU Policy on Worms in Fish


cleaning-fishBy Rabbi Chaim Goldberg, RC Fish

The Gemarah in Chulin 67b states that darna, a worm-like parasite, found in the flesh of a fish is permissible because “minei gavli” it grows in the fish. The Shulchan Aruch, Y.D. 84:16, quotes this halacha, and adds that worms found in the viscera (gut) are prohibited while worms found in the fish are permitted.

Recently there has been considerable discussion about worms in fish. Some Rabbonim understand the halacha (as formulated in Shulchan Aruch) to be that worms which hatch in the flesh are permitted, while worms that are swallowed whole and enter the viscera are prohibited.

Both of the worms migrate to the flesh. Based on this understanding these Rabbonim have stated that today, worms in fish are prohibited. This is because scientists maintain that contemporary worms known as Anisakis enter the flesh through the viscera and then migrate to the flesh. This is not a new issue and the question has been raised repeatedly in recent years. The OU has reviewed this matter and found it not to be an issue.

(Editor’s note) Rav Belsky confirmed unequivocally that OU policy remains that there is no checking necessary and no prohibition of the worms found in wild salmon and other fish, in accordance with Y.D. 84:16 for the following reasons: Shulchan Aruch does not limitthe permissibility of tolayim (parasites) found in the flesh of fish to any species of tolaas. The halacha states that a tolaas found in the flesh of a fish is mutar because of the rule of minei gavli [Chulin 67B], (that the parasite found in the flesh of the fish is permissible since it grew bigger in the fish) Rav Belsky cited Rashi in the Gemara as using the term gavul to mean that it “became bigger”, and he understood this to mean even if the worm originated and was visible to the naked eye outside of the fish, it would be permitted if it grew in the fish flesh. Rav Belsky felt there is no reason to believe the tolayim present today are any different from the tolayim discussed in Chulin and S.A. Rav Belsky felt this reason itself was sufficient to permit the matter, but added additional reasons to permit as follows: On his audio presentation for OURadio last year (available for review), Rav Belsky noted that Shulchan Aruch did not require one to be an expert in the tolayim found in the fish flesh to know how they got into the flesh, either from the viscera or from some other source.

Rav Belsky further feels that it is irrelevant whether the tolaas entered from the viscera or from some other way, whether it happened when the fish was alive or after it died. As proof, he notes that S.A. (ibid) says that tolayim which come after the death of the fish are permitted. Rav Belsky felt these tolayim must have come from the viscera, because there was no other reasonable source for tolayim entering a fish after death and yet they are permitted.

Some are concerned that the tolayim found in the flesh are actually the forbidden tolayim originally found in the viscera (Shulchan Aruch forbids the tolayim found in the viscera). Rav Belsky felt this claim is not based on any significant research. Rav Belsky felt that his own inquiries from qualified experts indicate that the opposite is true, and that the tolayim in question are found in the flesh while it was alive. Furthermore, Rav Belsky feels even tolayim entering the flesh from the viscera would be permitted as per above.

Rav Belsky confirmed that the size of the tolaas when it is swallowed by the fish is not relevant (even if it is visible while swallowed by the fish and visible when it migrates from the viscera). He also felt that reports that the tolaas is typically 5 mm is an exaggeration of the larger end of the spectrum recorded. He believes that nearly all of these tolayim when they are swallowed are between 1-2 mm long and quite thin (Rav Belsky felt they would be considered ayno nireh l’aynayim [halachically invisible]).

{Orthodox Union/Jerusalem Kosher News}

{Matzav.com Newscenter}


  1. Rav Eliyashev, Rav Wosner & Rav Karelitz have all banned the fish that have the annisakis worm. That would include all wild salmon (not farmed), canned salmon, many of the flounders, etc

  2. Rav Belsky is an odom gadol, and he is also drawing on the gedolim of chu”l who’ve dealt with this when it came up before.

  3. This is America. In America the American poskim posken. In EY the poskim of EY posken. Both are right – for their own groups in their own places.
    When Rav Kamenetzky Shlitah or the Roshei Yeshiva of BMG speak, then we should listen and do. why are we getting concerned until our own Gedolim speak?

  4. #1, actually this is not correct. Everyone who is “assuring” is only recommending people be machmir for fear of repercussions should they be matir. Try asking some of them (I have).