Rav Belsky’s Stance on the Kashrus of Worms in Flesh of Fish

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rav-belskyThe following is an article written for Matzav.com by a talmid of Rav Yisroel Belsky shlit”a explaining Rav Belsky’s stance on the anisakis parasite in fish on a basic level. To view Rav Belsky’s full teshuvah, click here.

By Rabbi A. Margolin

The tzibbur has recently been flooded with literature pertaining to a recent tumult in reference to the presence of parasitic worms in fish. The following is a synopsis of several shiurim that Hagaon Harav Yisroel Belsky shlita, rosh yeshiva of Yeshiva Torah Vodaath and senior posek of the OU, has delivered on the inyan.

The Gemara in Maseches Chullin says that sheratzim in water that never separated from the vessel holding the water are permitted to be consumed. The reason for this is because the Torah excludes such a creature from being a sheretz hamayim and, until it gets separated from the water, it is not a sheretz ha’aretz. Similarly, worms that are in produce that were not there while the fruit was attached to the ground are permitted for consumption provided that the worms did not leave the produce. Once again, it is not considered to be a sheretz; it is obviously not a sheretz hamayim, it is not a sheretz ha’of, and, because it was never on the ground, it is not a sheretz ha’aretz.

In short, a sheretz has to be classified as either a sheretz hamayim or a sheretz ha’of or a sheretz ha’aretz to be assur. Otherwise, it is permitted to be eaten.

The issue that was recently raised concerns the anisakis parasite. In a nutshell, the parasite’s eggs are found in a large amphibious creature such as a whale, dolphin, or seal. The microscopic larvae pass out with the excreta and are then consumed by a host known as crustaceans (shrimp-like creatures). In their host, the worm grows and may sometimes become nireh la’ayin. The crustaceans are eaten by kosher fish and thus the parasites end up in the stomach of a kosher fish. As parasites, the anisakis worm may bore through the fish’s stomach and work their way into the flesh of the fish.

The Gemara, as interpreted by Tosafos, says that the worms that are found in the stomach of a fish are forbidden, but the worms found in the flesh of the fish are permitted. The Bais Yosef in Yoreh Deah (Siman 84) says that the reason the worms in the stomach are assur is because perhaps they came into the fish as fully developed worms and thus were included in the issur of sheretz hamayim. [The Pri Megadim paskens this way as well.] This is unlike the worms that entered the fish that did not have the status of sheretz hamayim. In other words, when one observes worms in the stomach, one does not know if they are mutar or assur. The Shulchan Aruch rules clearly that worms found in the flesh of fish are always permitted. It is possible that Chazal knew that worms that were sheretz hamayim would not enter the flesh of the fish.

In summary, worms in a fish’s stomach are assur misafek and worms in the flesh of fish are permitted.

In the case of the anisakis worm, the worm in its microscopic state is not considered a sheretz hamayim; any organism not visually discernible by the eye has no meaning in halacha. Thus, this worm was never exposed to the water and is not considered a sheretz hamayim. The fact that it was “hosted” by a crustacean does not have any negative halachic effect as far as yotzei min hatamei (see Chavos Daas, Siman 81:2). [Even those who disagree with the Chavos Daas would agree in this case, since “minei gavli,” as will soon be explained.] We are not concerned that the worm was in the fish’s stomach prior to its migrating to the flesh and was thus considered assur; its assur status is only a safek, and once it is in the flesh, it is permitted.

Some claim that since the Gemara describes the worms that are in the flesh as “minei gavli, ” a worm is not permitted unless it can be ascertained that it was generated spontaneously by the flesh of the fish. This is because they define the word “gavli” as “being created.” However, since we became aware that all worms without exception come from outside sources, and there is no such thing as spontaneous generation in any shape or form, then, by extension, it is proven with complete certainty that the words “minei gavli” mean something else. Rashi, who says “lashon gadli,” defines the word gavli to mean “to grow.” This means that the worms in question entered the host in miniscule form and grew off their host. He gives no reference to the idea of spontaneous generation, a concept alien to Chazal and most certainly not required by halacha.

[Paranthetically, the common louse which Chazal describe as “eino parah v’rava,” commonly translated as meaning that it does not reproduce, does very certainly reproduce. Furthermore, its eggs, commonly referred to as nits, are visible to the eye. Nevertheless, one is permitted to kill it on Shabbos because of its status. Rav Belsky explains that the louse can not survive on its own; its survival is dependent on mooching off the host’s protein. In the case of a human, this is usually through the hair. Thus, we have another example how the words of Chazal have been misinterpreted.]

It is important to note that the Shulchan Aruch, when allowing consumption of worms in the flesh of fish, does not differentiate between worms; the heter is a blanket heter. Had there been a limitation on types of worms the, Shulchan Aruch would have indicated as much. This is especially true in light of the fact that the anisakis worm had already been identified in the time of the Mechaber. Futhermore, there is no way for a lay person without expensive equipment to determine which worm he is looking at – whether it is the anisakis or any other type of worm. If we were to forbid the anisakis, then we are forbidding all worms, contrary to the p’sak of the Shulchan Aruch!

In 1978, the Rashkebeha”g, Rav Moshe Feinstein zt”l, was asked about worms in the flesh of fish. He paskened, in accordance with the ruling of the Shulchan Aruch, that there was no concern.

One writer suggested that the p’sak of the Shulchan Aruch permitting the worms is limited to a specific parasite that enter the fish from the outside and is microscopic. This is simply absurd. Had the heter been limited to one type of worm, the Shulchan Aruch would have said so.

Another writer claims that a study in Norway found that the fish today are far more infested with anisakis worms in the flesh, because the fish lay packed together after they are dead and are therefore more prone to the parasites working their way into the flesh. This is in contrast to years ago when the fish would be cleaned immediately upon capture and there were very few worms in the flesh of the fish. Thus, it was a mi’ut sheaino matzui. This argument has no basis. The concept of miut sheaino matzui is in reference to when we have an issur, but we do not know how prevalent it is. When the likelihood is a low one, we do not need to consider it. Here, we are not talking about whether or not it is a rare occurrence. The point is whether or not worms in the flesh are assur or mutar, and the halacha is that they are mutar.

Others expressed concern that once we know that it is the same worm from the stomach that is migrating to the flesh and it is established that worms in the stomach are assur, how can those same worms subsequently become mutar in the flesh?

However, since the Bais Yosef explained that the issur is because it is a safek, there is no issue with them once they migrated to the flesh, as previously explained.

It is noteworthy to mention that a recently publicized letter which argues that anisakis should be assur is actually the most convincing proof that it is mutar. This is because all the reasonings stated therein to prove that the worms are assur would also apply equally to all other worms found in fish, rendering all worms in fish assur. However, this cannot be, since Chazal clearly state that they are all mutar. Thus, the only possible alternative, and consequently the truth, is to say that the reasoning is faulty and that they are all mutar. [The fault in the reasoning should be easily understood by anyone who read the forgoing material, but whether one discovered the flaw or not is immaterial, as no amount of reasoning in the world could lead to an absurd conclusion – that the p’sak of the Shulchan Aruch permitting worms is rendered obsolete.]

In conclusion, the p’sak of the Shulchan Aruch, permitting those worms found in the flesh of the fish, applies to the anisakis worm just as it applies to any other worm.

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  1. …, the parasite’s eggs are in a large amphibious creature such as a whale, dolphin, or seal…

    How did they get there?

    …However, since we became aware that all worms without exception come from outside sources, and that there is no such thing as spontaneous generation in any shape or form, then, by extension, it is proven with complete certainty that the words minei gavli mean something else…

    Just because we know that there is no spontaeous generation does not prove anything about what previous generations may have thought…Or how they used the words minei gavli.

    …This especially true in light of the fact that the anisakis worm had already been identified in the time of the Mechaber…

    Just because the anisaki had been identified in the time of the Mechaber does not prove that he was aware of all the science of his day.

  2. Thank you for posting this Tsuhvah.

    We now have clear Tshuvos of three Gdolei Torah, Mumchim in their fields, clearly explaining the reasons why the wild salmon and other fish are permissable, Muttar L’Chatchilah.
    1.) Harav Belsky, – 2.)Harav Falk (from Gateshead), – 3.) Rav Moshe Vaye.

  3. Rabbi Belsky, who is the kashrus authority for the OU and consequencially for almost every kashrus organizations in America because they all rely on the OU, is the Posek Achron in this matter. I don’t like worms. But the Shulchan Aruch does not require me to search for them. Case Closed !!

  4. To #5 In the first paragraph of this article it says click here in red ink, this has the whole Psak in Loshon Kodesh

  5. #1 – Are you kidding? Are you questioning Rav Belsky? Are you someone who has spent his entire life pouring over Seforim that when Rav Belsky says something you can question it? Are you questioning that the Mechaber did not know everything about science and animals? Do you think for a second that we would be using the Mechaber as we do if he didn’t?

    Do you think Reb Chaim Shlita knows everything about grasshoppers? Do you know the famous story? Of course without any shadow of a doubt whatsoever the Mechaber KNEW EVERYTHING!!!!!!

    Your nothing more then a modern day Apikores.

    Questioning the Mechaber? I repeat questioning the Mechaber? Did you actually just make a statement that the Mechaber did not know something?

  6. what comment #8 said to #1 is exactly what i wanted to say. and btw its not just the mechabur its the gemarah & rishonim.

  7. “sontaneous generation a concept alien to chazal and most certanly not required by halacha” WHAT?? look at tosfos on that sugya who writes “????? ?????? ?????? ?? ???? ????”.

  8. Rabbi Eidelman from MTJ said that he was once sitting next to R Moshe and they were eating fish and R Moshe pulled out a worm from the fish and told R Eidelman that that is the worm from the shulchan aruch and kept on eating. So R Moshe also holds that fish does not require checking.

  9. Isn’t anyone else repulsed that we now know that we are definitely consuming worms. Even if it is kosher…eeeewwwwww.

  10. “any organism not visually discernible by the eye has no meaning in halacha”
    My question is Why do we make such a big problem with strawberries, lettuce, etc. Am I missing something or are we being taken advantage of???

  11. #16: An insect being camoflagued against a background is still a “visually discernable” insect. Microscopic insects are those that are “not visually discernable”

  12. #16 I’m not a possek, but there is a difference between not looking for them, or not knowing what they look like, and not “possible to see them”.

  13. I’m sorry to say this but this is becoming “The Worm in The Fish Shayla” crisis. Let every person do as his Rav says. If a person ch”v has no Rav than he should be machmir. But its gotten to a point that everyone knows what everyone holds. And yet EVERYDAY we need another version of the same psak from each side. There is no need to repeat repeat repeat again and again and again each side. Let each person go ask his Rav. We, the people, don’t need to hear each side claiming that their side is not understood by the other side. It seems by all that there is a serious shayla. Each side has its points. Ask your Rav and Sholom al Yisroel. Amen


  15. Effectively, Rabbi Belsky shlit”a is today’s Rabbon shel kol Bnei Yisroel. Literally, millions of Jews in America and around the world relly on his Psak. Virtually evey kashrus organization relies on the OU for base products. These are fects.
    The recognized gedolim in Eretz Yisroel acquiesce when Rabbi Belsky speaks. That’s why the gabboim of certain Rabbonim don’t allow av Belsky in, for if Rav Belsky would be given access, those Rabbonim would agree with him.
    No one can pull the wool ove Rav Belsky. Y’chie Adoneinu Moreinu v’Rabbeinu l’arichas yomin tovim – amen !!!!

  16. Shoshana Miriam: You wrote:”It seems by all that there is a serious shayla.”
    I don’t agree; In R’ Belsky’s teshuva, he writes that there shouldn’t even be a need to write a teshuva, but since people “misled” the poskim, he must. There is a serious difference of opinion here.. Some hold it’s ossur, and some hold that it’s not even a shailo.


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