Further analysis of Rav Belsky's teshuva on Anisakis Worms in Fish

I recently read deeper into Rabbi Belsky's teshuva regarding anisakis worms in fish. There is a difference between what is written in the English summary, by a student, and the actual teshuva. The English summary is insufficient, IMHO, because while it refers to the fact that it is a safeik when found in the belly, and refers back to that point subsequently, there is not enough information to fully appreciate Rabbi Belsky's proof, and its implications as to why anisakas found in the flesh would be permitted. It is a pretty ingenious proof, I think. Still, I disagree with it.

As discussed in a previous post about Rav Belsky's teshuva, he insists that the gemara is not speaking of spontaneous generation, but rather of growing / developing within the fish. Which means that if the egg, (or some early stage of the worm -- namely the hatched larva) -- enters the belly of the fish when the fish swallows it, and then it develops within the fish, Chazal would say that such a thing was muttar, because it grew / developed within the fish. Why, then, should one found in the belly of the fish be prohibited? Though different theories are possible, the one put forth by the Beis Yosef (as understood by Rav Belsky) is that perhaps in its developed form, it was shoretz in the water and thus was assur, and subsequently was swallowed by the fish. Thus, it is a matter of safek, that when we see this developed worm in the belly, maybe it is muttar because it was swallowed in their earlier stage, or maybe it is assur because it was swallowed in its later stage. Therefore, it is assur misafek.

But if we find it in the flesh of the fish, then we know that it was not initially shoretz outside in the water; rather, it was swallowed into the belly in this earlier stage, and then moved into the flesh. Therefore, it is muttar. So from the existence of safek by worms in the belly, there must be a lack of safek by worms found in the flesh.

A large basis of this is the assumption that Chazal, and similarly Shulchan Aruch, are not discussing spontaneous generation, and thus are permitting them when swallowed at this early stage. This is based on a mistaken understanding of Rashi, I think, as I discuss in my earlier post, and a mistaken impression of Chazal. But Rabbi Belsky does have going for him this operating theory spelled out in Beis Yosef that the concern is that it was shoretz in the water. This works well with his explanation.

Still, I {=Josh} would point out that the words of the Beis Yosef can work out well with the assumption of spontaneous generation, just as well. (See here for a description of the life cycle of these worms.) Before being swallowed by the fish, the anisakis floats in the water, either as eggs or hatched larvae. These are eaten by krill. The krill are eaten by fish, and the anisakis worms then burrow out into the fish muscle or abdominal organs, and then lie dormant until the fish dies or is eaten by another creature. (It is still not it its fully adult stage -- it reaches that if the fish is eaten by a marine mammal. In this adult stage, it mates and lays eggs into the water.) If the larvae are considered developed enough to be sheratzim, then they can be shoretz in the water, and be assur. But if so, why should they be considered entirely permitted when found in the flesh rather than the stomach? Because Chazal, and the Beis Yosef, were mistaken about science. They believed in spontaneous generation, and believed that if found inside the belly, they could have come from outside (either as larvae or perhaps even, mistakenly, fully developed worms), but if found in the flesh, they could NOT have come from outside. Rather, they must have spontaneously generated from the flesh of the fish itself. Chazal did not believe that these parasitic worms were able to burrow into the fish's flesh. (Perhaps they are somewhat correct, in that after the krill is swallowed, they anisakis burrows out into the fish, into what is available and lies dormant until the fish dies -- at that point, it moves away from the place it has lain dormant.) If it spontaneously generated inside the fish, then it could never be shoretz in the water. Except of course that Chazal are wrong about spontaneous generation.

But again, Rabbi Belsky's assumption was that what the gemara and Shulchan Aruch meant was that fish found in the flesh must have come there from anisakis swallowed in the early stage, but not swallowed in the late stage. As stated very briefly, scattered in the English summary:

It is possible that Chazal knew that worms that were sheretz hamayim would not enter the flesh of the fish.

In other words, once something was shoretz in the water, it would never enter the flesh, but remain in the belly. Stated again later as:

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.

In other words, only while in the stomach is it assur, because we do not yet know that it is capable of migrating to the flesh, and so it might have been shoretz. However, once we see it in the flesh, the initial safek is removed, for it obviously had the power to burrow even into the flesh, which shows that it was swallowed in this early stage, before it could be shoretz. Therefore it is muttar.

Stated again later as:

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.

This is not well written, IMHO. But again, what he means is that since the issur in the belly is because of the safek, there is no issue once they migrate to the flesh, because this proves that they have the power to burrow into flesh, so they must have been swallowed in this early stage of development, and never had opportunity to be shoretz in the water.

This sounds like something we could subject to concrete experiment. What later stage of development does Rav Belsky want, that is actually found in nature. Take that, place it into the water such that it is swallowed by krill, place krill into water such that it is swallowed by salmon, and then investigate to see whether they only are embedded into the belly. Perhaps this will be so, but it seems like quite the stretch to me.

Where does Rav Belsky state this in his teshuva? When he states:

וא"כ שפיר נוכל לומר שאין ביכולת לתולעי איסור לבקוע דופן בני המעיים ולהסתתר שם. ורק לתולעת שהיא באמת חלק מן הדג, דמיניה קגבלי, יש לה כח הנ"ל.

That is, from the fact that Chazal don't consider it possible that it burrowed from one place to another in the flesh, we see that only one which developed in the fish will have such a power.

Indeed, Rabbi Belsky continues:

ובזה מיושב ג"כ מה שכתב המהרא"י בהגהות שערי דורא (שערי דורא אות מ"ז) שלא להקפיד לאכול דגים שיוצאין מגופן תולעים לבנים ורגילין לצאת מקצתן ולחזור, ואנו קורין אותן שויב"ן ולפעמים נמצאים במעיהם אותן התולעת וכשנמצא במעיהם רגילין להשליכן משום מיאוס עכ"ל. הרי שדרכם של דרני דכוורי לצאת לבני המעיים ולחזור, ולכאורה זה תמוה דאם יש כח לתולעת לבקוע כותלי בני המעיים,  איך כתבו הראשונים שהופעתם בבשר הוה הוכחה ברורה שלא באו מעלמא. ע"כ כדברינו שרק תולעת שאמרו עליו דמיניה קגבלי, יש בה כח לכנס ולצאת.

That is, in Hagahot Shaarei Dura, they relate that they are not makpid about certain white worms that come out of the flesh a bit and return, and sometimes are found in the belly, and when they are found in the belly, people throw them out (it seems only) because of mius, disgust. This should pose a problem both to Chazal and (certainly) to the Rishonim. Here is evidence that these worms can burrow! So how can the safek only be when it is in the belly?! Rather, it must be as he said, that worms which "develop within" (or I would say, spontaneously generate within) have this power.

If this is indeed the correct interpretation of Hagahot Shaarei Dura, that there is a difficulty does not mean that we must posit this reinterpretation. Maybe Chazal didn't know about this worm movement, and the Rishonim did not recognize the stira, or else the reality described by Hagahot Shaarei Dura. Certainly no one states this rule overtly.

But this whole difficulty comes from the words נמצאים במעיהם אותן התולעת וכשנמצא במעיהם
within the statement: שלא להקפיד לאכול דגים שיוצאין מגופן תולעים לבנים ורגילין לצאת מקצתן ולחזור, ואנו קורין אותן שויב"ן ולפעמים נמצאים במעיהם אותן התולעת וכשנמצא במעיהם רגילין להשליכן משום מיאוס עכ"ל.

However, when I looked in my Hagahot Shaarei Dura, I saw the text to the right, with that all-important phrase not present.

That is, a small portion of the worm leaves the body and then return. No mention of entering the belly. And sometimes, people indeed regularly toss them out -- these worms which exit partially and return. But this is just because of disgust, possibly, not because they maintain they are assur. And even those that left the flesh, we are not makpid about them, because we know that they come not from the outside world, but from the flesh of the fish, and that it is their practice to leave a bit (or in part) and return. Yes, the word במעיהן appears beforehand, and perhaps someone expanded the text on that basis, interpreting it as having breached the stomach barrier, as opposed to, e.g., going outside the fish entirely.

At the end of the day, we really need to know the correct girsa of this Hagahot Shaarei Dura. I suspect that what happened is that someone put explanatory comments in some citation from the Hagahot Shaarei Dura, in some printing, and Rabbi Belsky is making a diyuk based on the words that don't actually appear. Of course, perhaps those explanatory comments are correct, in which case the diyuk would be a fairly good one, though I could imagine a response or two. But it could well be that that was not the intent, and so we should not make this diyuk.

Also, this gloss is from Maharai, Rabbi Yisrael Isserlin, who was born 1390 and died in 1460. He is considered among the acharonei HaRishonim. Perhaps earlier Rishonim were not aware of this phenomenon involving worms. For example,

I would note that this is the gloss, the hagaha, to Shaarei Dura siman 47 which he cites. But if you look at the beginning of Shaarei Dura siman 48 itself, or as cited by the same Beis Yosef (d"h v'-kasvu), shortly after what Rav Belsky cited from Beis Yosef, you will note that he discusses בשר המותלע מחמת חום, flesh which becomes wormy due to heat. This means that Hagahot Shaarei Dura subscribes to spontaneous generation. As does Beit Yosef, who cites this without disagreement.

At the end of the day, Rav Belsky's theory is based on lack of spontaneous generation, such that Chazal must be referring to being swallowed at an earlier developmental stage, and such that there is a difference in migration. Indeed, the worms in the flesh certainly have migrated from the belly, but Rav Belsky transforms this into a reason it should be muttar, since it testifies to its not having been shoretz in the water.


But if I don't agree that Chazal asserted this, because it makes more sense for them to believe in spontaneous generation within the flesh; and I don't really accept, without evidence, that there is indeed a difference in actual metzius in power between worms which were swallowed at a different, or that Chazal or the Rishonim maintained this differentiation.


I wonder, though -- assuming that Chazal, and Beis Yosef did base themselves on spontaneous generation, perhaps portions of Rav Belsky's teshuva may be salvaged. After all, we still may say that Beis Yosef said that due to spontaneous generation, it was not shoretz outside in the water, and the real reason is the lack of being shoretz (as opposed to the competing theory, that spontaneously generated from fish are the fish and muttar, and since fish only need asifa, they are not ever min hachai). Similarly, if these were swallowed as eggs, they would not have been shoretz. But what about hatched larvae in the water? And what can we do about this assertion about inability to migrate? Does this have any scientific basis in fact?


If we could somehow show that no anisakis is shoretz in the water, because of its life cycle described above, then perhaps all should be permitted, even those found in the belly, because there is no longer any safek.


I believe there still are ways to be mattir these fish, without relying on the assumptions of Rabbi Belsky, and even aside from any suggestions I made immediately above.


Note: Don't rely on any of this for halacha lemaaseh.


Update: Apparently, from what I've read, there are indeed variant texts in Hagahot Shaarei Dura which would include this text.