Two weeks ago, YWN posted an article by Rabbi Mordechai Kuber regarding the current issue of ‘worms found in fish’. Rabbi Kuber states that there the worms are permissible to be eaten according to Halacha. We now present the following article written by Rabbi Chaim Scher, who is a “Boki in the Sugya”, which refutes Rabbi Kuber’s article:

Amidst all the turmoil about the fish worms, one point has become resoundingly clear: the view of the great Poskim has been widely misunderstood and misrepresented. If the article demonstrates anything, it is that the subtle and nuanced opinion of the prohibiting Poskim has eluded even some Rabbanim and Torah scholars. It is necessary, therefore, to restate their position accurately and clearly. In clarifying their position, we rely on a careful reading of Shevet Halevi 4:83, the letters of Rav Nissim Karelitz, and discussions with Rav Elyashiv that have been related to me.

Shulchan Aruch (Yoreh Deah 84) based on Chulin 67b states that worms found in the flesh of fish is permitted, while worms found in the viscera are prohibited. Rabbi Kuber, as well as many others, offers two options in understanding the Shulchan Aruch:

1: The Shulchan Aruch refers only to a specific worm known to Chazal to originate in the fish

2: The Shulchan Aruch offers a “blanket heter” that covers all worms.

Rabbi Kuber quotes Shevet Halevi as taking the first position; the heter only applies to a specific worm, and claims that while Shevet Halevi acknowledges that this position is at odds with Shulchan Aruch, he nevertheless adopts it.

If true, this would be an important milestone for Rav Vosner. After years of tireless study of Shulchan Aruch and after hundreds of responsa where Shevet Halevi bases Halachic decisions on Shulchan Aruch, Rav Vosner has graduated from deferring to Shulchan Aruch and has broken free from its iron grasp.

Why has he done so? The article has a ready answer. Rav Vosner places a premium on the opinions of scientists, not realizing that scientists are fallible and often lie. Furthermore, he has been misled to believe that this science is not based on science’s dismissal of spontaneous generation. Rabbi Kuber asserts that it is.

A careful reading of Shevet Halevi reveals that Rabbi Kuber has carefully selected excerpts from the Tshuvah. When the Tshuvah is read in its entirety, one finds that Rav Vosner, after suggesting that the Halachah permitting worms in flesh may apply only to specific worms and then proving that this is the opinion of Meiri, rejects this position because he interprets Shulchan Aruch to give a “blanket” heter.

Rav Vosner then proceeds to state his final position, his maskana; all worms in the flesh of fish are, under normal circumstances, assumed to originate in the fish. However, Shulchan Aruch’s “blanket heter“ does not cover a case where there is contrary evidence that the worm originated outside. The heter of Shulchan Aruch is no more than a vadai, a certainty, based on assumption, and not a biological impossibility.

It is not misleading for Shulchan Aruch to permit fish worms without caveat; all worms are covered by the heter. However, where there is evidence to the contrary, it should be obvious that the reasoning of the Gemara doesn’t apply.[1]

Do we, then, prohibit all worms that scientists believe originate outside the fish? Rav Vosner, in the same tshuvah, states clearly that we do not. He actually concurs with the opinion of Rabbi Kuber that scientists are prone to error and falsehood. If we find, however, that the science is not baseless, then the worms are certainly prohibited.

Rabbi Kuber maintains that all the science on this subject is baseless since science begins from the assumption that there is no spontaneous generation, an assumption which is clearly opposed to Chazal’s view. Were we to assume that these worms can be spontaneously generated, the article concludes, we would not be lead to assume that these worms have a multiple host life cycle, or that the anisakis worms migrate from the digestive tract to the flesh. The article implies that the great Poskim have been led to believe that the science here is not based on dismissal of spontaneous generation, while, in reality, it is.

Let us assume for now, as Rabbi Kuber does, that worms in fish will only be permitted if they are spontaneously generated. We then will proceed to analyze, as Rav Vosner suggests we do, the basis for which scientists have decided that the anisakis worm is not spontaneously generated. In this quest we need not look far; many scientists have generated anisakis larvae from eggs in vitro.[2] This does not disprove spontaneous generation in general. It merely proves that the anisakis worms are not from those worms that are spontaneously generated. The science on the non-spontaneous generation of anisakis is no more based on scientist’s general dismissal of spontaneous generation than are drug tests on mice based on the theory of evolution.

Surely, if Chazal would tell us that the anisakis worm is spontaneously generated, we would trust Chazal’s word over our own eyes, much the same way many Poskim permit killing lice on Shabbos. However, as Rav Vosner writes in the above Tshuvah in response to the questioner’s opinion that worms in fish flesh should be treated in the same way as lice, the issues are not comparable. Since the Gemara is not in direct conflict with empirical observation, the empirical observations about specific worms are treated much the same way we would treat a worm that we see migrate into the flesh; as a case that is not included in the stama of Shulchan Aruch.

Rabbi Kuber, in his embrace of spontaneous generation, offers a long-winded apology. He writes, “It is well known that spontaneous generation has been scientifically discredited by experimentation for the last 150 years.  Nevertheless, many teachings of Chazal hinge on a mechanism similar to spontaneous generation… we embrace spontaneous generation in this presentation, for it is the only way to explain the words of Chazal, without saying that they erred.  We mean not to dismiss experimental evidence, but just to acknowledge that some mechanisms are hidden.  We are not certain how fish flesh seems to develop into worms.  We know that it cannot be because of migrating larvae, but experimentation has also discredited flesh transforming to worms on its own.  But, we are mindful that there is much that we do not know, and that Chazal were well versed in nature, beyond their experimental abilities.  Hence, we invoke “spontaneous generation” as the non-invasive mechanism by which the fish flesh transforms to worms, even though we are not certain what that mechanism is.”

This apology resolves the questions regarding spontaneous generation only by being vague enough as to not be refutable, and does not dignify either Chazal or its author. Furthermore, the “hidden mechanism theory” does not explain the evidence by microscopy that lice, which the Gemara states do not come from eggs, can be observed to hatch from eggs. While we should embrace spontaneous generation, we should do so boldly and without apology. We trust the words of Chazal over what we can observe with our own eyes[3]. This is a feat which only Hashem’s chosen nation, the Maaminim B’nei Maaminim, can accomplish. For, in the end, it is not scientists’ words which we disbelieve in favor of Chazal’s tradition, but rather evidence that our own eyes may confirm.

It should be obvious that such dismissal is the exception rather than the rule. Normally, Halacha is based on a clear analysis of the empirical evidence before us, even in cases where the facts are different than those found in Gemara and Shulchan Aruch. One case in point, although not completely comparable to the issue at hand, is the Mishkenos Yakov’s ruling that we need to check for certain treifos which he found to be common other than the ones in the lung which Shulchan Aruch requires us to check. Did the Mishkenos Yakov search through stacks of scientific papers to determine if there was a change in the prevalence? Or, was he certain that we can determine the facts before us and rule accordingly, while assuming that the reason we were never required to inspect an animal for other treifos is not because his chiddush isn’t valid, but simply because the facts must certainly have been different? This is not to say that the cases are comparable. It is meant only as an illustration of what should be obvious: empirical evidence and even statistical data are dismissed only in exceptional cases and such dismissal is not normative halachic practice.

Perhaps, the ease with which Rabbi Kuber admonishes us to embrace conflicts between science and Chazal is, at its root, based on the ease with which he attempts to resolve them. He sees no need to stare the evidence in the eye and defy it; instead, he chooses to explain the evidence away with wordy apologetics. If he truly understood what it takes to dismiss empirical evidence, he may have realized that issues such as these are best left to Gedolei Yisrael.

In truth, however, according to many Poskim including Rav Elyashiv[4] and Rav Nissim Karelitz[5], a worm need not be spontaneously generated in order to be permitted. Any internal generation, even generation from an egg, would be permitted. Therefore, even worms that have been demonstrated to be generated from eggs may be permitted. It follows, therefore, that in order to prohibit these worms, it is not sufficient to prove that the worms generate from eggs; we must prove that they generate externally.

That there exists internal generation by egg is a notion that science is in agreement with. The species of Hufmanella, for example, have been reported to have eggs and adults in the flesh. A European parasitologist who has written several textbooks on Parasitology and has authored or coauthored many studies on parasites, has written as follows: “There are many helminth parasites that occur in fish flesh or skin. Frequently these are larvae of nematodes the adults of which are parasites of various piscivorous animals (fish, aquatic birds, mammals), some nematodes have only eggs in viscera, flesh or skin, but there are also adult forms with this location in the fish host.”

Since science is in agreement with the notion of internal generation, we may not dismiss the opinions of scientists out of hand because science doesn’t agree with the notion of internal generation; it does. True, science doesn’t begin from the assumption that worms cannot penetrate (although Rabbi Kuber erroneously misinterprets a CDC document as holding so); we maintain that Chazal didn’t assume so either, and will address this point shortly. However, to say that the Gedolim have been misled into thinking that the science on anisakis is not based largely on a general dismissal of spontaneous generation, while in reality it is, is wrong. If it is spontaneous generation upon which the heter is based, there is direct experimentation on anisakis that it is not spontaneously generated. If, on the other hand, it is internal non-spontaneous generation that we should consider in order to permit this worm, then scientists should be assumed to begin with an open mind.

We reiterate that if Chazal would tell us that the anisakis worm is spontaneously generated, we would trust Chazal’s word over our own eyes, much the same way many Poskim permit killing lice on Shabbos. However, as we have quoted earlier, Rav Vosner writes in his tshuvah that the issues are not comparable, since the Gemara is not in direct conflict with empirical observation. The empirical observations about specific worms are treated much the same way we would treat a worm that we see migrate into the flesh; as a case that is not included in the stama of Shulchan Aruch.

The assumption that forms the basis for much of the article is that the permissive ruling of Shulchan Aruch regarding worms in fish flesh is based on the inability of worms to penetrate fish organs. We will challenge this assumption later. However, for now, we will accept this idea. If the permissibility of fish flesh worms is based on the inability of worms to penetrate the digestive tract, then to prohibit anisakis worms we need only prove that these worms can penetrate and are therefore the exception. We do not have to prove actual migration.

Here again, if the ability of the anisakis worm to penetrate is all we need to prove, then we need not search far. There have been repeated experiments of infection of fishes by mouth in the laboratory and the anisakis worms were subsequently found in the liver.[6] Furthermore, the phenomenon of invasive anisakiasis, the ailment which has spurred most of the research on the Anisakis parasite, is based on the worm penetrating the intestinal wall, and in some cases, even leaving the alimentary canal entirely. This has been confirmed repeatedly by endoscopy.

[Rabbi Kuber brazenly exclaims the following:

“We also note that even the scientists are quite unclear about the source of the flesh worms.  The CDC (Center for Disease Control) states unequivocally that intestinal worms migrate to the flesh only after the host fish dies.  They are not discussing migration after the catch, but migration when fish die in the open waters and wait a while before being ingested by a larger fish.  Thus, the scientists admit that contemporary worms cannot pierce the intestinal wall during a fish’s lifetime.  Accordingly, they would be perplexed when asked to explain the presence of flesh worms that clearly did not migrate there in the short time between catch and gutting.  Thus, scientific theory actually points away from migration!” 

Here is the source in a CDC document for this statement:

Adult stages of Anisakis simplex or Pseudoterranova decipiens reside in the stomach of marine mammals, where they are embedded in the mucosa, in clusters.  Unembryonated eggs produced by adult females are passed in the feces of marine mammals .  The eggs become embryonated in water, and first-stage larvae are formed in the eggs.  The larvae molt, becoming second-stage larvae , and after the larvae hatch from the eggs, they become free-swimming .  Larvae released from the eggs are ingested by crustaceans .  The ingested larvae develop into third-stage larvae that are infective to fish and squid.  The larvae migrate from the intestine to the tissues in the peritoneal cavity and grow up to 3 cm in length.  Upon the host’s death, larvae migrate to the muscle tissues, and through predation, the larvae are transferred from fish to fish.  Fish and squid maintain third-stage larvae that are infective to humans and marine mammals.  When fish or squid containing third-stage larvae are ingested by marine mammals, the larvae molt twice and develop into adult worms.  The adult females produce eggs that are shed by marine mammals.  Humans become infected by eating raw or undercooked infected marine fish.  After ingestion, the anisakid larvae penetrate the gastric and intestinal mucosa, causing the symptoms of anisakiasis.

Rabbi Kuber mistakenly understands this to mean that host transfer occurs only after death of first host when the larvae migrate to the flesh. This is an error. The CDC is actually referring to the most common point at which worms enter the flesh; post mortem/capture. The CDC put these two unrelated events in the same sentence because they occur in the same stage of the lifecycle. Rabbi Kuber’s acknowledged ignorance of the relevant scientific data has led him to misread the CDC description of the anisakis lifecycle. Unless the CDC based itself on Rabbi Kuber’s understanding of the Gemara in Chulin 67, there is no source, scientific or otherwise, that anisakis cannot penetrate live flesh. This understanding is also illogical. There is no reason that worms should need to migrate to the flesh of a host in order to be in a position to enter another one. Neither the CDC nor any scientists would be shocked if anisakis burrowed its way into the flesh. Anisakids are equipped with a boring tooth, and boring into flesh is no more difficult than boring into any other organ. ]

Can one still argue that Chazal maintain that no worm can penetrate the digestive tract, and we must dismiss the evidence that anisakis is an exception? Perhaps. But one cannot have his cake and eat it too. One cannot permit worms on the basis of the impossibility for a worm to penetrate, and also say that evidence that anisakis is an exception is weak by poking holes in the migratory evidence. For, if it is the possibility of penetration we are investigating, the evidence is as solid as any confirmed by experimentation.

Thus, we take exception to the following statement by Rabbi Kuber: “As best as this author could determine, there seem to be no more than a handful of papers, upon which the arguments of the prohibiting camp are based.  These few reports are all that has been disseminated as evidence of migratory worms, and seem to be all that is available in the public domain.  This paltry evidence of nature-change seems as mismatched against the weight of tradition and the Shulchan Aruch’s blanket ruling as is an untrained featherweight against a champion heavyweight fighter.”

If the evidence seems mismatched, it is only because Rabbi Kuber has pitted the migratory evidence against the supposed impossibility of penetration. Rabbi Kuber’s supposition that Chazal see penetration by a worm as impossible, an assumption Rabbi Kuber crowns as a “champion fighter”, should be pitted against evidence of a different kind; that confirmed by endoscopy.

However, as we will demonstrate later, the prohibiting Poskim do not accept the premise that the heter of fish flesh worms are based on the biological impossibility of worms to penetrate. The evidence for anisakis ability to penetrate is, therefore, according to these Poskim, not sufficient to determine that the anisakis worm is an exception.

What then is the evidential basis for prohibiting the anisakis worm?

Before we address this question, we need to restate clearly the Poskim’s understanding of the Gemara’s basis for permitting fish flesh worms.  The Gemara’s permissive ruling is not based on a biological impossibility of worms penetrating to the flesh, but, rather, on a known fact that worms in fish flesh are internally generated. This, according to the Poskim, is the meaning of the phrase mentioned by the Rishonim, “certainly they have generated internally”. Worms normally found in fish flesh can be assumed to generate internally. Rav Vosner explains this to be the root of the disagreement of the Rishonim with regard to fish flesh; whether or not one may, in absence of contrary evidence, assume that worms in fish flesh have generated internally. We will soon show that this can be extrapolated from many Rishonim.

There is broad agreement among the Poskim that the Gemara refers only to a case where there is no contrary evidence. Furthermore, many take the position that to prohibit a specific worm in fish flesh, we need not even provide definitive proof that the species is externally generated. Even evidence of doubt would be sufficient to question the assumption that a certain worm has internally generated. Where there is a reason to question the assumption, we will assume that the case is an exception. However, in absence of such evidence, we will assume that a worm is covered under the “blanket heter” of Shulchan Aruch.

Thus, the thousands of parasites found in fishes whose life cycles have not been adequately studied, or those whose generation have been studied and have been determined to generate internally, will be permitted based on the assumption that they have generated internally. However, with regard to worms whose lifecycles have been extensively studied by scientists and have been found to generate externally, there is disagreement between the Poskim. An example of this is the disagreement with regard to the White Fish worms. Poskim, such as Rav Elyashiv, maintained that these worms too should be prohibited[7]. Others maintain that scientific studies of the lifecycle of a worm are based on scientific theory rather than fact. When scientific opinion regarding the generation of a worm is not such that can be demonstrated in a laboratory, and there is no directly observable evidence in the fish itself, we will assume that such a worm is covered by the “blanket heter” of Shulchan Aruch and is not an exception to the rule.

With regard to the anisakis parasite, however, since there is directly observable evidence for doubt that the worms generate externally, even those Poskim who permit the worms in White Fish[8] agree that this worm should be prohibited.

Rabbi Kuber mistakenly assumes that these Poskim believe that the directly observable evidence regarding anisakis’ generation is incontrovertible, and therefore attempts to show that it is not. The Poskim certainly are aware that it is not possible to prove with complete certainty that a worm has externally generated. It is always possible to dismiss evidence with imaginative theories. However, since they understand the Gemara as permitting fish flesh worms based on a known fact rather than a biological impossibility, they see no reason to do so. They see a situation in which there is directly observable reason to doubt the internal generation of a worm as a case regarding which the Gemara, if such a case would be brought before them, would rule strictly.

Evidence which is directly observable in a fish is not, by definition, a counter argument to Chazal. It is merely a case which is inherently different than the case mentioned in the Gemara.

This nuanced and well reasoned position of the great Poskim of Israel has been widely misunderstood. Rabbi Kuber misrepresents their position, and only in the last third of the article briefly alludes to such a position and dismisses it summarily.

We now turn to address the substantive argument that Rabbi Kuber makes to permit the fish. Rabbi Kuber argues that the Gemara’s heter of worms in fish is based not on known circumstantial evidence or assumptions that the worms in the flesh of fish originated inside the fish, but rather on a biological impossibility that a worm can bore through the digestive tract and infest the flesh. The sole substantive proof for this offered by the article is that, with regard to kokyana, the Gemara does not consider the possibility of the worm entering the fish via the mouth. This, the article asserts, is the argument of the Gemara of “Lishtakchu Derech Bais Hareii”; Worms that enter by mouth can follow only the route of the digestive tract. They cannot penetrate into the flesh. If this is the basis for the heter, then, the article implies, the standard of evidence necessary to assume a worm is boring its way through the digestive tract cannot be met based on the directly observable evidence of doubt provided by the prohibiting camp. After all, if we truly believed that a worm cannot bore its way through the digestive tract, we would not be swayed by this evidence. Were we to visit, for example, a high security prison, and we would see a few people in prison garb just near the door on the outside, we would not be convinced that they escaped. If we assume that the Gemara maintains that it is impossible for a worm to bore through the digestive tract, than the observable evidence may not be convincing.

Let us examine Rabbi Kuber’s proof that the Gemara’s initial suggestion that kukyana originate inside the fish was based on the biological impossibility of worms boring through the flesh. Rabbi Kuber asks: Why did the Gemara not suggest a simple entry point; the mouth? It must be, Rabbi Kuber says, that it is impossible for worms to penetrate the digestive tract and enter the flesh.

If this is a valid question, then let us pose it on the Knesses Hagedolah and Meiri (who, as Rav Vosner writes, holds, like Knesses Hagedola, that the permissive ruling applies only to a specific worm called darna or morna). The Gemara explains the prohibited worms enter through the ear or nostril. How do they reach the flesh? Can worms penetrate to the flesh? Furthermore, let us now pose Rabbi Kuber’s question:  If these worms are burrowing through to the flesh, why did the Gemara ignore the more obvious route; via the mouth? Obviously, Rabbi Kuber’s answer that worms cannot penetrate to the flesh is not the correct answer to this question.

Before we point out that the answer postulated by the article is not correct in the Rambam either, we need to correct Rabbi Kuber’s misunderstanding of the Rambam. Rabbi Kuber writes the following:

“Magid Mishneh explains that Rambam holds that only dead flesh will generate worms.  Therefore, he concludes, worms found anywhere in a freshly caught fish are prohibited, because they could not have generated within the fish, but rather must have invaded from the outside.  Rambam discusses only gut worms, for those were all that were prevalent in his days, but Magid Mishneh reveals the law for any worms that one day might be found in the flesh.

According to this approach, we have an additional understanding of why Rav Sheishes opens the discussion about kokyana by stating that they are certain invaders (see above, The Contrary Opinion of Most Rishonim and of the Halachah).  Since live flesh cannot generate worms, the only possibility is that kokyana are invaders.  This could be Rambam’s source for his position.

Thus, we see that Rambam disagrees with Shulchan Aruch’s permissive ruling regarding flesh worms in freshly caught fish.  Nevertheless, we see that Rambam’s reason is not that he is minimally or maximally concerned about invaders, but rather because ante-mortem worm generation is impossible, and therefore all worms must be invaders.  Hence, Rambam actually indicates the opposite of what the opposing camp claims.  We could happily dismiss claims of invasion and migration if internal generation were possible.  But before death, worm generation is impossible, and our only choice is to recognize that somehow the worms invaded.”

Rabbi Kuber understands Magid Mishneh’s explanation of Rambam to be that live flesh cannot generate worms. This is impossible, since the Gemara clearly contemplated permitting kokyana. Since there is no basis for permitting worms in fish if they have not generated internally, the Gemara must have allowed for a possibility of internal generation. When, in the end, the Gemara prohibits kokyana, it is only because the possibility exists that they entered via the nostrils; not because live flesh cannot generate worms. Thus, Rambam does not dismiss internal generation in live flesh at all. Rather, it is the possibility of a worm to migrate to the flesh that is of concern.

We can now pose Rabbi Kuber’s question on the Rambam’s position. If Rambam allows for the possibility of worms invading the flesh, why does the Gemara not entertain the possibility of entrance via the mouth? Here again, Rabbi Kuber’s answer falls short. The Rambam clearly allows for the possibility of flesh-invading worms, yet does not contemplate entrance via mouth.

In fact, the answer falls short in the Maharshal and Bach as well. Rabbi Kuber’s assertion that the Maharshal is concerned only with post catch contamination in limited circumstance is incorrect. Maharshal clearly permits only worms in a whole fish where there is evidence that the worms have not migrated to the flesh. One such example is a worm lodged between the skin and flesh with no apparent means of entry.[9]

Thus we may now pose Rabbi Kuber’s question to Bach and Maharshal as well. Since they clearly assume migration from gut to flesh is possible, why did the Gemara not consider the mouth as a point of entry?

Two Rishonim, both quoted by Rabbi Kuber incorrectly, offer answers to this question.

As mentioned, Rav Ashi in Chulin 67 offers as proof that kukyana generate internally the fact that they are not found in the (end of) digestive tract.[10] Rashi seems to interpret this to mean not that they should be in the digestive tract only and not in lung and liver, but rather, that the kukyana should be also in the digestive tract.[11]

According to Rashi, then, worms can migrate via the digestive tract. The Gemara’s proof that this does not occur with kukyana is that if kukyana enter via the digestive tract, we should be finding them there as well.

[We correct two errors in Rabbi Kuber’s interpretation of Rashi:

A: There is no evidence that Rashi explains the Gemara differently than the other Rishonim, aside from the basic difference; according to Rashi the Gemara refers to worms in lung and liver of animals, as opposed to fish. On the contrary, many Acharonim[12]  offer reasons for Rashi’s translation of kukyana as animal parasites. They obviously did not assume any new elaborate interpretation by Rashi. We do not see where Rabbi Kuber derived his interpretation of Rashi.

B: Rabbi Kuber claims that according to Rashi the kukyana go through the rectum and reenter the lung and liver. Does this mean that they exit the body completely? If so, then they must be able to reenter some other way aside from the ear/nostril. Why, then, does the Gemara not assume that they enter the viscera through that other way without the long detour through the digestive tract? On the other hand, if they do not exit the body, then they are penetrating the rectum and migrating to the viscera; an assumption Rabbi Kuber certainly would like not to have to make.]

Thus, Rashi holds that migration from digestive tract to flesh is entirely possible. With kukyana, however, the Gemara had a proof that they did not start out in the digestive tract, since they would then have been sometimes found there. It follows, then, that with a worm that is constantly found in the digestive tract, such as the anisakis parasite, we may assume migration from digestive tract.

The second explanation as to why the Gemara did not consider entrance by mouth is offered by Meiri. Meiri states that kukyana could not survive the digestive tract and therefore could not have originated there.

Accordingly, Meiri holds that migration to flesh is possible. However, the worms in question cannot survive the digestive tract and could not, therefore, have originated there.

It follows, again, that the anisakis parasite which has been proven to survive the digestive tract can be suspected of migration to flesh.

[Rabbi Kuber uses Meiri’s explanation to explain why worms would be found in the belly area. He mistakenly assumes the belly area to be the part of the fish in which a worm found would be forbidden. This is an error. The belly flap is flesh. This being the case, there is no logic to his argument. In fact, Rabbi Kuber has missed the entire point of this piece of migratory evidence; in many fish the worms, when in flesh, are found only in the first 2 cm of the belly flap. The rest of the anisakis load is in the viscera.

Perhaps, the root of this confusion lies in the anatomical or halachic error of the next paragraph, where Rabbi Kuber describes kukyana as infesting the gut!]

Rabbi Kuber later proves from Meiri that Meiri holds that worms cannot migrate to flesh. As we have just proven, the exact opposite is true.

If worms can migrate to the flesh, what, then, is the basis for the certainty that flesh worms are internally generated? One might consider that the certainty is based on Rashi or Meiri’s explanations of the gemara’s assumption that kukyana don’t enter by mouth. Thus, we would limit the Heter of Shulchan Aruch to either a worm that either cannot survive the digestive tract or a worm that is never found there. Furthermore, this would not explain why we are not concerned that a worm, having entered through the ear/nostril of the fish, did not migrate to the flesh.

We find the answer clearly stated in Hagahos Shaarei Dura, who permits schwibrin, worms which burrow from the flesh to the surface and back. Why does he permit these worms?

Rabbi Kuber writes of the Hagahos Shaarei Dura the following:

“He permits white shwibrin worms that we observe burrowing from the surface deep into the flesh of fish, for we are certain that they originate within the fish flesh.  Rav Isserlin understands that even when we witness penetration of these worms, we may presume that they were originally internal, since we often find them in the flesh, and are therefore aware that they develop within the flesh.  Rav Isserlin is not concerned that these burrowing worms are originally external, and hence prohibited.  Regarding flesh worms, we presume that they developed internally even when the possibility of external penetration is present!”

If we read the Hagahos Shaarei Dura carefully, however, we see clearly the basis for his having permitted the worms. He writes, “we permit them because it is evident and known that they grow from the fish itself”. We permit flesh worms not on the basis of an inherent proof that worms could not penetrate, rather, we permit them because it is evident and known that these worms originate in the fish. It is for this reason that according to some versions of Hagahos Shaarei Dura, he permits even those shwibrin found in the viscera. Since it is known that these worms, which predominantly occur in the flesh, originate in the fish, we may permit them even when we find them occasionally in the viscera.

It is clear from Hagahos Shaarei Dura that the basis for permitting flesh worms is the known fact that they originate inside the fish, not the biological impossibility of penetration.[13]

It is likely, then, that if a worm were predominantly found in the viscera and only occasionally in the flesh, Hagahos Sharei Dura would prohibit them. This is precisely the opinion of the Poskim who prohibit the anisakis worms in fish based on the directly observable evidence; where most of the parasite load is in the viscera, even the few worms in the flesh are forbidden.

It should be noted that it is not, as Rabbi Kuber claims, tandem infestation of viscera and flesh that is the concern, rather it is the constant high prevalence in viscera compared to the flesh, in addition to the proximity of the worms to the viscera, that points to the fact that these are visceral worms (which we suspect of originating outside) and not flesh worms.

The same point; that flesh worms are permitted based on a known fact can be extrapolated from Meiri as well. However, in Meiri’s opinion it seems this knowledge is limited to a specific worm called Morna. In the opinion of other Rishonim, this knowledge is not limited and can be assumed, in absence of contrary evidence, to apply to all worms. However, we need not assume that the Rishonim disagree on the basis for permitting the worms. They disagree only as to how far reaching it is.

Rabbi Kuber asserts that Meiri agrees with the “blanket heter” of Shulchan Aruch. However, Shevet Halevi extrapolates from the Meiri the opposite; that he holds the Gemara’s heter is only regarding a specific worm. That this is the intent of Meiri is obvious to the careful reader. Meiri, after explaining that the halachah permitting worms in flesh is because they generate internally, then goes on to translate the word morna. In doing so he writes, “morna is a worm that is found in fish flesh and surely has generated from the fish itself”. Obviously, Rav Vosner points out, this is the definition of morna. When Meiri writes it surely has generated from the fish, he means that Morna is a worm that surely has generated from the fish.

Having derived this meaning in the Meiri, we can now conclude, as Rabbi Kuber writes, “then it follows that Raah and Ran phrase their justification for the permissibility of fish morna similarly to Meiri, and they should be explained in the same manner.” When the Rishonim say that flesh worms have certainly generated from the fish, they do not refer to a biological impossibility for worms to penetrate the digestive tract, but rather to a known phenomenon regarding fish flesh worms that they generate internally. This does not mean Raah and Ran agree with Meiri that the permissive ruling of Gemara applies only to a specific worm; they very well may not. Rather, this means that when the Rishonim say Vadai, they mean that it is a known fact, not a biological impossibility.

Rav Vosner’s opinion is now clear; The Rishonim disagree only as to the Halacha of a case of stama; a case where there is no evidence in either direction. The debate is whether the Gemara permitted us, based on a known phenomenon, to assume that these worms are generated in the fish. Where there is evidence about specific worms to the contrary, the permissive ruling is then rendered baseless in regard to that worm, and is prohibited. The opinion of the poskim who do not rely on scientific studies of the lifecycle to prohibit the worm and are prohibiting based on the directly observable evidence that these worms migrated from the viscera are saying something even more basic; the Gemara makes the assumption only with regard to worms which evidence points to origination in fish. At the very least, where the evidence points to the contrary, or even where it points only to migration from viscera, the Gemara would consider such worms questionable. There need not be incontrovertible evidence to prohibit a worm. Evidence pointing to migration from viscera, by itself, renders the worm impermissible.

Rabbi Kuber notes, correctly, that Pri Megadim (Sif’sei Daas 84:43) and others comment that visceral worms are not certainly prohibited, but only out of doubt that they might have arrived from the outside.  It is also possible that they developed internally, as is the case with flesh worms.  He asks, “So why should we be concerned about the presence of stomach worms, which might well have developed internally and be permitted?  We cannot permit them, because we are not certain, but that doubt should not foster speculation about possible migration to these possible invaders.”

This logic is flawed. If flesh worms seem to be coming from the viscera, then they should be prohibited, whether with certainty or out of doubt, in the same way the visceral worms are. If a worm found in the viscera is considered to be a safek, how can that safek be cleared up by the worms migration to the flesh?

In short, the question before us is not whether we follow Chazal or science; the question is, rather, what does Halachah hold regarding a worm that seems to enter from the viscera? Is it to be considered as a flesh worm or a visceral worm? The prohibiting Poskim have answered the question clearly: they are treated as visceral worms.

Rabbi Kuber quotes the opinion of Rabbi Moshe Mordechai Karp that the anisakis worm is prohibited in the following way:

“Rav Moshe Mordechai Karp, a distinguished neighborhood Rav in Kiryat Sefer who has championed this cause, suggests that many Rishonim and Poskim, and perhaps even Shulchan Aruch, do not issue a blanket ruling.  Rather, they permit flesh worms only if we are certain that they do not originate outside the fish.  However, they are prohibited if reasonable doubt exists concerning their origin.  Thus, migratory worms of yore that were comparable to contemporary worms, which are purportedly migratory, were prohibited even in Talmudic days, and the Talmud’s permissive ruling refers only to non-migratory worms, whose origin is certainly within the fish (Ohr Yisroel, Teves 5770).”

The above quote is somewhat contradictory. Does Rabbi Karp permit flesh worms only if we are certain that they do not originate outside the fish, in which case we do not need evidence of reasonable doubt in order to prohibit the fish, or do we prohibit worms only where reasonable doubt exists that they originated outside the fish? What does Rabbi Karp hold in the normal case of fish flesh? In truth, Rabbi Karp is of the opinion that there is a basic assumption that worms in flesh originated in the fish. He acknowledges, however, that Maharshal holds that one cannot eat fleshworms unless one has proof that they originated within. It is reasonable, then, to assume that even those Poskim who possibly argue with Maharshal, agree that where there is reason for doubt, even fleshworms are prohibited. Thus, this opinion is not contrary to Shulchan Aruch’s “blanket heter”. All the holes Rabbi Kuber tries to poke in the migratory evidence do not affect the basic point: there is reason to suspect these worms migrated from the viscera.

Rabbi Karp is not, as stated by Rabbi Kuber, promoting that we follow minority opinions; he is merely maintaining that, in the case of anisakis, the opposing opinions also agree that it is prohibited.

Rabbi Nosson Geshtetner, an elderly accomplished Gaon and Rav from Bnei Brak, takes a slightly different position to prohibit these worms. He writes in his sefer L’horos Nosson vol. 9 that if it appears that these worms have migrated from the viscera we need to assume that there was a nature change since the times of Chazal and Shulchan Aruch and these worms are prohibited.

Seemingly, it is in response to this argument that Rabbi Kuber writes, “Suggesting that nature has changed since the days of the Talmud is not novel; Magen Avraham (173:6) and Maharshal (Chulin 7:15) suggest the same.  However, granting credence to scientists as arbiters of post-Talmudic change is quite a departure from the halachic norm of old”.

We will not be presumptuous, and will allow the reader to choose who, between Rabbi Geshtetner and Rabbi Kuber, should be granted credence as an arbiter of Halachic change. We hope, however, that Rabbi Kuber’s omission of the sources in Rishonim for nature change does not mean that he has not become familiar with them before lecturing to Rabbi Geshtetner.

We also note that Rabbi Geshtetner did not find it necessary to search through the relevant scientific papers to examine if this nature change has been confirmed by science. He maintains that we need only find evidence of migration from viscera to flesh in order to assume a nature change. There is no burden of proof for actual nature change in order to prohibit these worms. The position of Rabbi Geshtetner is bolstered, however, by the widely reported increases in infestation of the anisakis parasite in fishes, which could easily lead to these worms infesting fish flesh even though they had, in the past, only infested the viscera. According to some reports, new post-capture handling practices have also contributed to increased infestation in flesh. While the evidence for this may not be incontrovertible, it is enough to refute the almost reflexive response by those wishing to permit these worms that surely these worms have always infested the flesh of fishes since creation.

Before we address the scientific evidence dismissed by Rabbi Kuber, we begin, by way of introduction, with Rabbi Kuber’s own introductory statements. Rabbi Kuber writes, “It behooves us to evaluate independently the integrity and legitimacy of the presented migratory evidence, even without invoking the against-Chazal disqualifier”. The reader has thus been assured that he will be presented with an objective evaluation of the migratory evidence, an evaluation not tilted in favor of the alleged differing position of Chazal.

Let us quote from the first paragraph of Rabbi Kuber’s refutation of the migratory evidence:

“The fourth proof is the easiest to brand as presumptuous, because it could well be that the belly flaps are more accommodating to worm generation than are other locations.  In a vacuum, stomach proximity might cause us to postulate about migration, but it is far from compelling enough to begin to challenge the universality of the Shulchan Aruch’s ruling. (We will present below the minority opinion of one Rishon who understands that worms invade from outside the fish to its belly, and not to within its stomach.  Therefore, we would expect to see a predominance of belly worms, according to his opinion.)”

We ask: Is this the objective evaluation of the migratory evidence the reader has been promised?

In truth, Rabbi Kuber has missed the entire point of this evidence. This part of the migratory evidence is based on the fact that in many fishes, the only area of flesh infested by anisakis larvae is the 2 cm of the belly flap closest to the viscera. To explain this with the opinion of Meiri is a confirmation of the prohibiting position; these flesh worms have invaded from the outside!

Let us analyze the objectivity of Rabbi Kuber’s refutation to the third proof; anisakis is not prevalent in farmed fish. Rabbi Kuber writes “The third proof of migration seems more credible, for what else could account for the noticeably lesser incidence of infestation in farmed fish than in wild fish?  (We interject that we have yet to see documented proof of this disparity of incidence.)  Again, although less comfortably, we contend that this argument is unconvincing when contrasted with Shulchan Aruch’s position that worms of his day did not migrate to the flesh.  Instead of postulating that nature has changed, we could argue that controlled farm conditions are less conducive to worm generation than are the wild, polluted waters of the oceans”.

Is this the promised analysis of the migratory evidence “without invoking the against-Chazal disqualifier”? The parenthetic interjection too has no merit; we urge Rabbi Kuber to ask any fishmonger if farmed fish is infested by anisakis before engaging in armchair philosophy. The argument that controlled farm conditions are less conducive to worm generation than are the wild polluted waters of the oceans appears to be an error. Farmed marine fish are raised in miles of polluted ocean that are caged off. These waters are some of the most polluted in the world. However, we suspect that Rabbi Kuber would now argue the opposite; the polluted waters in which farmed fish are reared are less conducive to anisakis generation.

We have already dealt, we believe adequately, with the refutation of the second proof. We note only that the proof itself has not been presented correctly by Rabbi Kuber. It is not tandem infestation that is the issue, but rather the very strong prevalence of anisakis infestation of many fishes in the viscera compared to the flesh.

Rabbi Kuber makes two arguments against the supposition that post-mortem migration is responsible for anisakis infestation in fish flesh because fish are left ungutted:

A: Anisakids infested in fish flesh are encapsulated.

B: Rabbi Revach’s demonstrations of post-mortem migration are not reliable.

We have already noted that it is this migration that the CDC is referring to. This is the opinion of the World Health Organization and the FDA as well. The Dutch have reduced the incidence of anisakiasis significantly by gutting fish soon after capture. Several studies have shown large scale migration from viscera to flesh after capture.[14] In the fish in which large scale migration to flesh after capture has been shown, the larvae are not encapsulated. In some fishes, it has been shown that there is no large scale migration after capture. In these fishes the larvae in flesh is encapsulated.

Some scientists also suggest that the disease in humans has increased when refrigeration was introduced on fishing boats. Previously, fish had been gutted immediately.[15]

The implication of Rabbi Kuber’s article that the Gedolei Yisrael have been, somehow, misled is illogical. Rabbi Kuber maintains that the very idea that a worm found in the flesh of fish originated outside is in opposition with the Halachah. Do the Gedolim agree with this notion? If so, then what could they have been told that would lead them to prohibit a worm? Have they been told that people have begun to eat infested fish guts? There is no question that they don’t accept the premise that unless we actually see a worm enter the flesh it is permitted. They have also not been made to believe that the Gemara doesn’t actually say lishtakchu derech bais ha’reii. They have not been told that divers followed an anisakis larva from the feces of whales to its ingestion by a Krill to the krill’s ingestion by the salmon.

They have been told that anisakids are disproportionately prevalent in the viscera of many fishes. This is undisputed. Some may have been told that there is evidence of migration after death (or capture). That this is true has been well documented in many fishes. This science is not based on external generation; it has not been reported in other parasites, and is not even true with regard to anisakis in some fishes.

We need not invoke a doctrine of infallibility to think it foolish to assume the Gedolim have erred. It is often the case that people have an easier time disagreeing about Torah with experts of Torah, while they would never consider challenging an expert doctor in matters of medicine. In this, we commend Rabbi Kuber for his consistency; he has done both.

A Rav lauded in the article for rushing in where Gedolei Yisrael fear tread has said at a kashrus conference that the permitting argument is correct because a Rav who permitted the worms has written the longest responsum on the subject. If one judges by that Rav’s criterion for quality, Rabbi Kuber’s article has ensured that the permitting argument will prevail. However, we trust that the intelligent kosher consumer will find in this response the tools to remove the sand Rabbi Kuber has thrown in their eyes.

11

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[1] See Yad Malachi, Klolei Haposkim 2

[2] Koie and Fagerholm (1994), Moravec 2009, Adroher et al (2004)

[3] See Tshuvos HaRashba

[4] As quoted by Rabbi Moshe Mordechai Karp

[5] In conversation with Rabbi Gershon Bess

[6] Koie and Fagerholm(1994), Moravec (2009)

[7] Bedikas Hamazon K’halachah

[8] Such as Rav Nissim Karelitz, see Bedikas Hamazon K’ halacha by Rabbi Moshe Vaie.

[9] See Bais Efrayim Y.D. 25 that the word Chaticha means the flesh as opposed to between skin and flesh. See also Rashba Chulin 67

[10] See Pleisi 84 that in a fish the corresponding organ would be the gut.

[11] This is evident from Rashi’s explanation of the Gemara’s answer that kukyana enter the ear/nostrils when the animal is asleep. Rashi explains this and then continues, “therefore they are not found in the digestive tract”. If the question was only how the kukyana entered, then the end of the sentence is meaningless since the entry point has already been explained.

[12] See Pleisi ibid.

[13] See also Rosh Efraim Kuntres Hatshuvos 15

[14] Myers (1979), Smith and Wooten (1984)

[15] Jay (2005)

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