This week’s leading American chareidi newspapers feature an advertisement confirming the ruling of Rav Yosef Shalom Elyashiv forbidding the consumption of fish that contain very small anisakis worms in their flesh. This includes most fresh saltwater fish, including salmon, halibut, flounder, sable and cod. Some also include herring. They permit farm-raised fish. The ad, signed by Rav Aharon Schechter, Rav Feivel Cohen and Rav Dovid Feinstein, does not state their own views, but rather makes it known that the two senior poskim, Rav Elyashiv and Rav Shmuel Halevi Wosner, have paskened that the fish are forbidden to be eaten.
Rav Yisroel Dovid Taub, the Modzitzer Rebbe in Flatbush, who has written a lengthy teshuvah on this topic, has been quoted as saying that although Rav Elyashiv has said that these fish are forbidden to be eaten, nonetheless, in a personal conversation with Rav Elyashiv, Rav Elyashiv related that he did not have the energy himself to analyze and investigate all the factual and statistical information that this shailah involves, and he therefore based his ruling solely on the research performed by the bais din of Rav Shmuel Halevi Wosner. There have been those who have contended that the factual material presented to Rav Wosner’s bais din was not entirely accurate. Others defend its accuracy.
Also this week, an ad from Rav Yisroel Belsky, rosh yeshiva of Yeshiva Torah Vodaas, and Rav Moshe Vaya, one of the leading bedikas tolaim experts in the world, was published in chareidi newspapers, making clear that those who rule leniently on this issue are following the rulings of Rav Moshe Feinstein, Rav Shlomo Zalmen Auerbach and other poskim from the previous generation who were asked this very shailah and issued permitted rulings. The individuals who asked Rav Moshe and Rav Shlomo Zalman the shailah emphatically claim that it was the exact same shailah and nothing has changed, and they firmly believe that those poskim would permit the consumption of the fish even today.
When asked about this, Rav Dovid Feinstein, rosh yeshiva of Mesivta Tiferes Yerushalayim, responded that he never spoke to his father, Rav Moshe, about this, adding that he has not researched the issue himself and therefore cannot issue his own ruling. He did note that Rav Elyashiv is machmir.
Many of the Chassidishe poskim have permitted the consumption of the fish containing anisakis based upon the rulings of Chassidishe poskim of the previous generation who were consulted at that time.
The issue remains a machlokes amongst poskim, and every person must follow the ruling of his or her rov.
In light of the recent attention being paid once again to this matter, Matzav.com presents a full overview of the shailah that was recently published by Halacha Berurah Publications and written by Rabbi Elli Bohm, a rosh chaburah at Bais Medrash Govoah in Lakewood, NJ. While the article was reviewed by Rav Yisroel Belsky, a strong proponent of the stance of the matirim, the article was written as a complete overview, clarifying, in detail, the opinions of those who rule stringently and those who rule leniently.
To download and print a pdf version of the Halacha Berurah article in its original form containing extensive footnotes, click here. The full article can also be read below.
Rabbi Bohm can be reached at email@example.com with any comments.
Worms in Fish – The Recent Controversy
By Rabbi Elli Bohm
Reviewed by Harav Yisroel Belsky
Prior to the commencement of this discussion, it is imperative to mention that it is not our intent to take any sides on this issue, but rather to give an overview of the shailah and discuss the various opinions and scientific facts on the subject. It is the obligation of each reader to follow the opinion of their rov.
THE PROHIBITION OF SHERATZIM
In a previous issue we discussed that there are three categories of insects. 1. Sheretz ha’aretz – terrestrial insects. 2. Sheretz hamayim – aquatic insects. 3. Sheretz ha’of – flying insects. In this issue we will be discussing Sheretz hamayim – aquatic insects. Four issurim are transgressed for each of these insects consumed.
Two of the terminologies used by the Torah in describing insects are shekatzim and remasim. The Rambam maintains that the term shekatzim refers to insects that multiply from eggs deposited by female insects. The term remasim refers to insects that reproduce spontaneously (i.e., on their own) from manure or rotting carcasses.
The concept of spontaneous reproduction concerning insects is alluded to by Chazal as well. Chazal in Maseches Shabbos state that one who kills lice on Shabbos is potur, since lice are not poru verobu. They don’t multiply from a parent lice. Instead, as Rashi explains, they sprout from human flesh.
These statements have caused a bit of confusion in light of contemporary scientific belief. Much research has been done in this area, and after numerous experiments, scientists claim to have negated the theory of spontaneous reproduction. For example, it had been believed that maggots reproduce spontaneously from decaying material. After much research, it was discovered that flies actually deposit microscopic eggs in decaying materials. The living or rotting material furnishes heat for the hatching of the eggs and food for the newly hatched maggots. Thus, it may seem as if they spontaneously emerged from the decayed material.
Furthermore, a common insect found in vegetables are aphids. They, too, seem to spontaneously emerge from the vegetables. In truth, however, in autumn, the females lay fertilized eggs that survive the winter in crevices and hatch in the spring. These eggs produce wingless females that reproduce without fertilization from males. After several generations, winged females are produced. They then migrate to other plants and continue reproduction of wingless females. Toward the end of summer, winged males are produced and fertilize the winter eggs.
The question which must be addressed is how to accept the contemporary scientific theory in light of Chazal’s statements.
THE INITIAL STAGE OF THE ISSUR
In a previous issue we explained that the Torah only prohibits terrestrial insects that have crept on the ground. Insects that developed inside a detached plant or any other food item and never crept out from inside the food are permitted according to the Torah. If the insect emerged at all from the plant or food, it is forbidden to eat the insect even if it crawled back inside. In halacha, this is called ‘piresh.‘
However, insects that developed in a plant while still attached to the ground are considered by the Torah as having crept on the ground and are forbidden even before they emerge. (In order for it to be forbidden, the insect itself must develop while the plant is attached to the ground. It is inconsequential when the egg was laid.) .
The same applies to aquatic insects, as will be discussed below.
Worms can be found in fish either in the stomach, in the flesh, between the flesh and the skin, or they can cling to the outside of the flesh. The worms that cling to the outside of the flesh are forbidden to be consumed. Such infestation is commonly found in carp. Placing the fish in vinegar or a salt solution is helpful to remove these worms. Preferably, these fish should be cleaned by trained fishermen, as proper cleaning is arduous and requires skill.
Worms found inside the stomach are forbidden misafak. Worms found in the stomach may have either spontaneously been produced inside the stomach or these worms may have developed outside the fish and then entered the fish. Therefore, these worms may have the status of sheretz hamayim, and are forbidden misafak. Care must be taken when filleting the fish to cut out the stomach while it is whole, so that the worms don’t crawl out and get mixed with the fish. A number of local fish store workers have been seen chopping up fish without paying much attention to the fact that the stomach splatters open and the worms come into contact with the fish, cutting boards and knives. This commonly occurs when they recklessly process white fish at a rapid pace. Consumers should be wary of this and should only patronize fish stores where the workers are interested in proficiency rather than productivity.
Chazal in the Gemara clearly state that worms found in the flesh of fish – which we eat – or between the flesh and the outside skin of the fish are permitted. Chazal state that these worms definitely developed inside the fish and are therefore permitted. These worms are not considered to be sheretz hamayim, since they developed inside the fish, and as long as they are still inside the flesh, they are permitted to be eaten and one is not required to chop up the fish to search for these worms and remove them.
Approximately thirty years ago, some people started a commotion, questioning the long accepted custom to eat fish containing worms in its flesh. The uproar revolved around the modern scientific belief that every single worm that is found inside the flesh originated, at some point, from outside the fish; as they reject the theory of spontaneous reproduction.
The two worms popularly discovered in various fish are the Anisakis, also known as the Herring Worm, and the Pseudoterranova, also known as the Cod Worm.
Scientists have claimed that these worms undergo a lifecycle. It begins with adult worms that live in the stomach of marine mammals such as seals, dolphins or whales. Their eggs pass into the sea, and when they hatch, the larvae are eaten by other insects such as copepods which are then eaten by crustaceans (i.e. a classification that includes copepods, krill, and shrimp). These crustaceans are then eaten by large fish, and the worms are released into the stomach of the large fish (e.g., salmon, cod, and herring). The worms then supposedly pierce through the stomach wall and enter the flesh of the fish. These fish – if not caught first – are then eaten by a marine mammal, which completes the life cycle and begins a new one.
The question that needed to be addressed was how to understand Chazal’s statement that the worms develop inside the flesh of the fish and are therefore permitted, when contemporary scientific belief is that all the worms we find in the flesh originate from outside the fish.
At the time, the question was asked to virtually all gedolei Yisroel. Almost all were matir. The Hisachdus Harabbonim held a meeting and they were matir. The Debriciner Rov, the Pupa Rov, the Klausenberger Rov and many other chasidisha Rabbonim, were matir as well.
The shailah was presented to Rav Moshe Feinstein zt”l, Rav Shlomo Zalman Auerbach zt”l, the Minchas Yitzchok, Rav Yisroel Yaakov Fisher zt”l, and ybl”c Rav Yosef Shalom Elyashiv and Rav Nissim Karelitz. They were all matir.
Close to fifteen years ago, the shailah was once again raised concerning whitefish. At that time, they presented the shaila to the Gedolei Eretz Yisroel, that these worms are only found in the flesh of wild fish which swim in the open water and thus can be a part of a lifecycle, while farmed fish do not contain such worms. Almost all rabbonim were nonetheless matir, with the exception of Rav Wosner, who still maintained that is preferable to be stringent and refrain from eating these fish. Rav Elyashiv at that time was also a bit more skeptical, due to the distinction discovered regarding farmed fish, but he did not issue a definitive ruling.
In truth, the above distinction was already presented to Rav Moshe zt”l fifteen years earlier by the belzer dayan, and he was not fazed by that observation, as will be pointed out later on in the article.
WHAT CHANGED RECENTLY
Recently, some individuals decided to examine fish themselves and took notice of an abundance of worms in the stomach of the fish and found the same looking worms inside the flesh of the fish. They wondered whether perhaps the reason why the rabbonim who were previously matir these worms did so because they said that we do not believe the scientists when their word contradicts Chazal. Now, however, it is not just a matter of whether we believe the scientists that the worms found inside the flesh originate from the stomach and from outside of the fish. We, ourselves, have an indication of this well.
Additionally, in the fish that were checked, it was discovered that the worms in the flesh were in the area of the belly flaps, indicating to the examiners that the fish migrated to the flesh from the stomach. Some worms were even seen protruding slightly into the inner cavity from the flesh.
Based on these indications, some individuals approached Rav Wosner, who ruled that these worms must not be those that Chazal discuss, and although, until now, it was just a matter of whether or not to believe the scientists, now that we have our own indications that they may migrate from the stomach to the flesh, one must definitely be stringent.
The shailah was then brought to Rav Elyashiv, who, relying on Rav Wosner’s bais din‘s examination of these indications, ruled that if there are indeed such indications, one must be stringent in regard to these worms.
In order to reconcile the statements of Chazal with these findings, they claimed that all the worms that Chazal discuss were of a different extinct species which developed inside the flesh. These worms, they said, no longer exist nowadays, and the Anisakis, Cod Worms, and thousands of other parasitic worms which we do find in our times were either not in existence during the times of Chazal or were uncommon enough that Chazal did not discuss them.
To try to give some credence to this assertion, the individuals who recently brought the shaila to the rabbonims attention suggested that perhaps due to pollution and global warming, Anisakis and Cod Worms are more common in our generation. Additionally, some claimed that these Anisakis and Cod Worms predominantly migrate postmortem because of the fish not being gutted properly.
It is based upon these findings that Rav Elyashiv, Rav Wosner, and a number of other gedolei Eretz Yisroel, issued letters that although people were previously lenient, it is now time for people to act stringently and refrain from eating fish containing such worms.
THE OPINIONS OF THE RABBONIM WHO PERMIT
There seem to be two approaches amongst the rabbonim who permit the consumption of fish containing the worms, despite the above indications.
Many of the chassidishe poskim who permit the fish take the words of Chazal at face value and maintain that Chazal believed in spontaneous reproduction and it is unreasonable to say that the worms we find today are different than the worms that Chazal discussed. Some have also furnished scientific reports which state that the scientific belief that the fish originate as part of a lifecycle initiated by larvae excretions of mammals is only a hypothesis and is not a scientific fact. Therefore, they claim that to establish that the origination of these worms differ from Chazal‘s description, we need conclusive proof or at least very convincing evidence. Since these rabbonim discredit the above indications, as will be demonstrated below, and we on our own do not observe any evidence contrary to what was stated in Chazal, we have the right to take the words of Chazal at face value.
Many of the Litvishe poskim who permit the fish maintain that even if we do accept the contemporary scientific belief that the worms originate from outside the fish, they are still mutar. Chazal were masters in science in addition to having a special hasgacha formulating halacha and although they may have described their reasoning obscurely, it is our obligation to toil in order to elucidate it and reconcile it with contemporary scientific beliefs. The halacha does not change. They claim that this has been the opinion of many gedolei Yisroel who were consulted regarding this very shailah years ago.
We will discuss their reasoning in the following two sections. The first section will focus on the first approach, analyzing the aforementioned indications, and the next section will discuss the latter approach.
THE FIRST APPROACH – ANALYZING THE INDICATIONS
Various individuals spent a significant time researching this entire matter and questioned the indications on which this shailah was based and which resulted in the stringent ruling by gedolei haposkim in Eretz Yisroel.
At a recent meeting of rabbonim, one of these individuals, gave a two-hour presentation producing a plethora of reports to demonstrate that there is no convincing indications that the worms found in the flesh of fish originate from outside the fish. He therefore maintained that there is no compelling reason for us to be forced to say that the metzius changed from the times of Chazal and the Shulchan Aruch.
We will briefly delineate the retorts they offered to dismiss the indications on which this shailah was based.
Indication 1: Same Type of Worm Found In Stomach and In Flesh
Many of the worms found in the flesh are deeply embedded. Additionally, they are lying dormant. Therefore, some questioned why one can’t safely assume that they were created in the location where they were discovered, just as chazal state. The fact that you find the Anisakis worm inside both the stomach and the flesh, they claimed, should be no indication that they migrate from the stomach to the flesh. Perhaps, the fish produces these worms in both the stomach and in the flesh. The only reason why we cannot eat the worms in the stomach is because of the possibility the fish may have also swallowed worms. Therefore, when worms are found in the stomach the poskim say it is forbidden misafek. However, in the flesh chazal confirm to us that they were definitely created there.
In fact, this observation of finding them in both locations is not new to the Torah World. It is already discussed by some rishonim, who describe the characteristics of these worms in a manner which strongly resembles the worms we presently find. Additionally, approximately twenty years ago, people presented this very shaila to the beis din in Antwerp, claiming to find these worms in both locations, and the Rabbonim, including Rav Padawa zt”l and yblc”t Rav Falk shlit”a and Rav Tuvia Weiss shlit”a, were all matir it nonetheless.
Moreover, some demonstrated from a scientific viewpoint, that there are so many subspecies of the Anisakis worm, and scientists can differentiate through subtle differences which subspecies they believe are part of which lifecycle and originate from which type of larvae excretions. Scientists are constantly discovering additional varieties of the Anisakis worms and keep on creating new subspecies and reclassifying them. Therefore, they said, just because it appears to us to be from the same species found in the stomach and the flesh, perhaps, in fact, they are not the same species. Just as ongoing scientific research keeps producing new subtle differences, resulting in new sub-species categories, perhaps one day they will realize that Chazal were correct and the Anisakis worm found in the flesh may indeed be different than those found in the stomach that originated from outside the fish.
Furthermore, many statistical reports demonstrate that it is very uncommon to find these worms in the stomach of Salmon and we generally only find them in the flesh. Therefore, the fact that some fish may have them in both locations is not necessary any indication of migration.
Additionally, some explained that there might as well be Anisakis worms found in the stomach which may have in fact migrated from the flesh to the stomach, rather than vice versa. Indeed, some of the early poskim mention such a concept.
Therefore, some questioned that if this entire issue of sub-classification is so relatively new to the world of science, why should we be compelled to place present scientific hypothesis against the words of Chazal and the Shulchan Aruch’s unequivocal heter and claim that nishtaneh hatevah?
Indication 2: Infestation in the Area of the Belly Flaps
Regarding the claim that there is a greater presence of Anisakis worms in the area of the belly flaps, indicating that the worms originated from the stomach, the matirim maintain that this is far from conclusive. In fact, in many fish, the worms are far more commonly found in the double fillet. In some fish, it depends upon the season, the location of capture and the age of the fish.
Additionally, although at one point scientist did indeed hypothesize that the reason why many fish have a greater presence of worms in the belly flaps, is because they migrated from the internal cavity. However, scientists have since then refuted this hypothesis for a number of reasons. Firstly, in younger fish the width of the belly flap is approximately ½ of an inch. The worms are found in the first ¼ of an inch. We do not find any proportional pattern to have these worms further embedded in older fish as the belly flaps grow to an inch thick. Moreover, as mentioned above in certain fish there is a greater abundance in the double fillet then in the belly flaps area. Basically, in order to establish any theory, we would have to have some sort of pattern to give credence to the theory. In this case, no pattern exists. On the contrary, the lack of pattern indicates that it is not hinged upon any migration from the stomach area. Therefore, to establish indications, claim the matirim, based upon minimal laymen research defies all normative statistical researching procedures.
In fact, some scientists suggest that the worms may just find the belly flaps area more comfortable to be in, either due to its fattier portion or for some other reason. Therefore, in many fish, they may migrate to that area even from other areas in the flesh.
Indication 3: Protruding Worms
We mentioned above, that the occurrence of finding protruding worms into the internal cavity has already been alluded to by some rishonim, who permitted them. The matirim proved that it is impossible to tell without much experience and the use of a microscope which side is the head of the worm and which side is the tail, since these worms are so tiny. Therefore, when the rishonim permitted fish that had protruding worms, they had to permit all worms even worms whose head is pointing towards the flesh indicating that it is originating from the internal cavity.
Indication 4: Farmed Fish Distinction
In response to the claim that the worms are found in the flesh of wild fish and not the flesh of farmed fish, the matirim maintain that perhaps this is simply a result of the nutrition of the fish, and, again, there is not sufficient indication to contradict the words of Chazal and prove that the worms are part of a lifecycle originating from mammals. Additionally, as mentioned above, this distinction was already presented to Rav Moshe zt”l approximately thirty years ago by the belzer dayan, and he was not fazed by this observation.
Indication 5: Postmortem Migration
The matirim also discuss the claim of postmortem migration which was raised recently. There are dozens of studies, they say, stating that that the Anisakis worms are found in the flesh while the fish are still alive, unlike what others have suggested that the migration to the flesh occurs only after death when the fish are not gutted properly.
In fact, at one point science did believe that although worms do exists in the flesh while the fish is alive, postmortem migration does nonetheless frequently occur if the fish is left ungutted for a number of days. However, there are various recent reports where scientist refuted this original theory. They examined a lot of fish shortly after capture, those placed on ice, those left ungutted, and those gutted in the same manner as they are gutted commercially, and there was no greater incidence of infestation in any one of the processes. The only instance in which there was increased infestation was in the uncommon case of a fish being left in a warm temperature for 24 hours prior to being gutted and properly cleaned. The standard procedure is to gut the fish shortly after capture, unless the fish is frozen.
Additionally, many of the Anisakis worms are found deep in the flesh and encapsulated by the flesh, indicating clearly that they were there while the fish was alive, as encapsulation cannot happen after death.
Synopsis of this Approach
Those who raised the original shailah countered these arguments by stating that the indications they originally presented are strong enough to support the claim that perhaps these worms are not the worms that Chazal permitted. The scientific world is convinced that they originate from the outside. This, they claim, adds further credibility to the original indications which they discovered.
The matirm, following this approach, feel that since none of the above indications, in their opinion, have any basis, one may safely continue the status quo, and continue eating the fish we have been eating for years. Additionally, they claim, that it is highly unreasonable to say that only after Chazal‘s worms became extinct, these worms came around, for if they were in existence during Chazal’s times, then Chazal could not have issued a blanket statement that all worms found in the flesh of fish are permitted. Moreover, Anisakis is documented to have existed as early as the 12th century.
Contemporary rabbonim who are matir the worms, point as well to the fact that this is an issue which affects almost every type of fish we eat and have been eating for generations – and claim that the wide ramifications of the shailah in addition to the many statistical inaccuracies of the above indications was not properly presented to the gedolei Eretz Yisroel who ruled stringently.
THE SECOND APPROACH – THERE IS NO CONTRADICTION BETWEEN CHAZAL AND CONTEMPORARY SCEINCE
As mentioned above, many of the Rabbonim who permit the fish maintain that even if we do accept the contemporary scientific belief that the worms originate from outside the fish, they are still mutar. Chazal were masters in science in addition to having a special hasgacha formulating halacha and although they may have described their reasoning obscurely, it is our obligation to toil in order to elucidate it and reconcile it with contemporary scientific beliefs. The halacha does not change. They claim that this has been the opinion of many gedolei Yisroel who were consulted regarding this very shailah years ago.
Reconciling Contemporary Science with Chazal
Some suggest that even if we accept the origination of these worms to be part of a lifecycle initiated by copepods or shrimp swallowing larvae, nonetheless, chazal considered the worms to have originated within the fish. They explain that since the larvae are microscopic in the sea, at the time they are swallowed they are halachically non-existent, and therefore Chazal considered them to have developed within the fish. It is these worms which are found inside the flesh and the ones Chazal permitted. The stomach, however, may also contain regular worms which the fish swallowed when they were much larger, and therefore, said Chazal forbade the worms found in the stomach misafak.
Some questioned this approach based upon a scientific report claiming that the larvae ingested by the crustaceans are not microscopic. However, the matirim have demonstrated many reports clearly stating that they are indeed microscopic and said this only report indicating that the larvae are not microscopic was written by a medical doctor whose expertise is not in parasitic studies related to marine life.
Another option suggested by some poskim to reconcile contemporary science with chazal is based upon the terminology of Rashi in describing the permissibility of the worms found inside the flesh. Rashi states that since their growth occurred in the fish, they are permitted. Therefore, these poskim maintain that there is a difference between parasitic worms and regular worms that fish might swallow. Ordinary creatures which reproduce from regular eggs, their eggs contain all the nutrients for the development of the organism. Parasites, however, hatch from very simple eggs, and their entire development comes from latching on to a host organism. Without that, they would have no means of survival and development. The worms that Chazal were matir are parasitic worms, whose entire growth and development had to occur inside the fish. It is therefore considered as if it originated there and does not have the status of Sheretz hamayim. This is unlike ordinary worms found in the fish’s stomach, which the fish swallowed at a later stage.
The poskim following this approach maintain, that even if none of these reconciliations are appealing, then it is our obligation to come up with another explanation, in same manner as we would do for every other sugya in shas. However, the halacha does not change.
Synopsis of this Approach
In summary, these matirm accept the idea that these worms have originated at some point from the outside of the fish, nonetheless, since chazal unequivocally say that they are muter the halacha does not change. It is our obligation to toil as we would do for any other sugya in shas and try to clarify and elucidate Chazal’s reasoning in the light of contemporary scientific knowledge. Chazal were masters in science in addition to having a special hasgacha formulating halacha and although they may have described their reasoning obscurely, it is our obligation to elucidate it.
These matirim claim that there are thousands of types of such parasitic worms and they are found in almost every fish in the ocean. It is reasonable to assume that these worms have always existed and are the very same worms that Chazal discuss, since there are no indications of any change in nature. It is unreasonable to state that there has been a climatic or procedural change from the times of Chazal.
The Opinions of the Gedolim of the Previous Generation
Reb Shlomo Zalman Auerbach zt”l
Rav Moshe Vaya, one of the foremost Torah experts globally on insect infestation and bedikas tolaim in food, says that he presented this exact shailah to Rav Shlomo Zalman Auerbach zt”l years ago, and Rav Vaya told Rav Shlomo Zalman that the worms are found inside the stomach and inside the flesh. Rav Vaya described the entire lifecycle of these worms as well. Rav Shlomo Zalman was very firm in his response, stating that Chazal clearly said that worms found inside the flesh are mutar, and that this is the final halacha.
Rav Vaya related to Rav Shlomo Zalman that perhaps we can reconcile Chazal‘s statement that they spontaneously reproduce inside the flesh with contemporary scientific belief that they originate from larvae outside the fish based upon the microscopic explanation offered above. Rav Shlomo Zalman liked this explanation very much.
Rav Vaya says that the feeling he got from speaking to Rav Shlomo Zalman was not that the reason why he was matir the worms was because our evidence is based on scientific reports but that if we ourselves had indications it would change the issue. Rather, he was matir simply because Chazal, who were experts in areas of science and had special Hashgacha when formulating the halacha, ruled that they are permitted. Thus, the halacha does not change and we are forbidden to think that they erred, chas veshalom. To assume that nishtaneh hatevah – that nature has changed – without concrete evidence of a change in nature is also not reasonable, explained Rav Vaya. Therefore, it is our obligation to find methods to reconcile the words of Chazal with science, and it is for this reason, he says, that Rav Shlomo Zalman was happy with the microscopic sevara which serves this very purpose.
The Minchas Yitzchok
Rav Vaya also presented the shailah to Dayan Yitzchok Yaakov Weiss, the Minchas Yitzchok, in the same manner, describing as a matter of fact the metzius – that we find the same worms in the stomach and in the flesh. In a lengthy shailah that he penned to Dayan Weiss, Rav Vaya only touched upon scientific reports briefly towards the end of his question. Dayan Weiss was also unequivocally matir the worms.
Reb Moshe Feinstein zt”l
It seems that Rav Moshe Feinstein took a similar approach when dealing with this shailah. Rav Moshe, close to thirty years ago, was approached by two rabbonim who brought many scientific reports to show Rav Moshe. Rav Moshe refused to even examine any of the evidence, stating that it does not matter what evidence they showed him, since the halacha won’t change, as Chazal say it is mutar. Rav Moshe was very firm about it. They asked him if he would write a teshuvah on this matter. Rav Moshe smiled and asked, “You need me to write a teshuvah to reaffirm what is already printed clearly in the Shulchan Aruch so unequivocally?”
The matirm strongly believe that Reb Moshe zt”l would still be matir nowadays, as had it been possible for an indication to sway Reb Moshes opinion and consider the option of nishtana hateva, he would have been open to examine the evidence. For all he could of have known, was that the people standing in front of him might have had some x-ray technological reports videoing the worm entering the fish and borrowing into the flesh. Reb Moshe, could not of have been so firm and refuse to look at any reports, had he not taken the above approach that halacha does not change and we must toil to enlighten the reasoning of chazal, in light of any information we presently have.
Relying on the Opinion of the Gedolim of the Previous Generation
The matirim claim that even if the indications that were presented to the contemporary gedolei yisroel are accurate, then at the very least, it is quite reasonable to say, we would nonetheless have a machlokes haposkim, with Rav Moshe, Rav Shlomo Zalman, the Minchas Yitzchok, and others strongly permitting the consumption of these worms based upon the seemingly same shailah which they responded to years ago.
Those who recently raised the shailah countered these arguments by stating their belief that the only reason why the rabbonim of the previous generation were matir these worms was because they did not believe the scientists when their word contradicts Chazal. Now, however, it is not just a matter of whether we believe the scientists that the worms found inside the flesh originate from the stomach and from outside of the fish. We, ourselves, have an indication of this well. Therefore, they are not convinced that these gedolim would have permitted the fish in these times.
The matirim, however, stress that the ones who consulted the rabbonim of the previous generation are still alive, and they strongly believe that the shaila nowadays is the same as when they spoke to the rabbonim of the previous generation. Additionally, the feeling they got from speaking to the rabbonim was not that they were matir because we don’t believe the scientists. Rather, they were matir simply because Chazal, who were experts in areas of science and had special Hashgacha when formulating the halacha, ruled that they are permitted and the halacha does not change. Therefore, it is our obligation to find methods to elucidate the words of Chazal in light of contemporary scientific knowledge.
These parasitic worms are commonly found in herring. In fact, the Anisakis worm is commonly referred to as a Herring Worm, even when found in other types of fish.
Some poskim maintained that based on the facts that were presented to them, the presence of parasitic worms in the flesh of herring is a much smaller percentage than in the other types of fish, and therefore there are grounds to permit the consumption of herring. These poskim considered the infestation level in herring to be classified as a mi’ut hamotzui, for which there is only an obligation Miderabonon to check. Therefore, they said, in cases where there is only a rabbinic obligation to check, and checking is impossible even under ultraviolet light due to the color of the herring, one is exempt of this obligation and may assume that there are no worms in the piece of herring one is set to consume.
Others contended that one can indeed find worms in herring by performing an inspection. Additionally, scientists have found by using a pepsin digestion method, that 70% of Norway herring fillets are infested with these worms, thus making the obligation to check the fish min haTorah.
Therefore, there are those who say that if one would forbid these worms, one would have to forbid all herring as well.
All agree that fish may be ground, such as gefilte fish, when making salmon patties, or a salmon spread. Even if there is a worm inside the fish, it would be botul. Although we generally say that insects are not botul, that is only when the insects are whole, but once they are ground, they are botul.
The Rashba maintains that cooking food containing worms does not necessarily disintegrate the worms and the cooked food remains a safeik. Some claim that in canned fish which are heated in a pressurized retort that is heated up to a few hundred degrees for a few hours, the worms definitely become disintegrated. Even the fish inside the actual can may reach 250 degrees Fahrenheit. Some claim to have found worms in canned fish that were still whole. Even if this is true, it is debatable how rare of an occurrence this is. Some poskim, maintain, that there are additional reasons to permit canned fish, even according to the poskim who forbid these worms (see footnotes for an elaboration).
The shailah of parasitic worms in fish was discussed by gedolei haposkim approximately thirty years ago. Recently, there were those who claimed that they themselves found indications that the worms found in the flesh of fish indeed migrate from the stomach to the flesh and the shaila should therefore result in a different ruling then it did when analyzed years ago. They presented the shailah to the gedolei Eretz Yisroel, many of whom ruled stringently.
The rabbonim who are matir say that this is an issue which affects almost every type of fish we eat and have been eating for generations and not only to certain exotic fishes, as these parasites are found in almost every fresh water fish. They claim that the wide ramifications of the shailah in addition to the many statistical inaccuracies of the above indications was not properly presented to the gedolei Eretz Yisroel who ruled stringently.
Additionally, the matirim feel, that it is, at the very least, a machlokes haposkim, with Rav Moshe Feinstein and Rav Shlomo Zalman Auerbach being matir even today.
As we stated at the outset, it is not our intent to issue a p’sak, but rather to provide an overview and present a synopsis of the various opinions.
To download and print a pdf version of the Halacha Berurah article in its original form containing extensive footnotes, click here.