Chullin 97a: Rava said: At first I had a difficulty with the following Baraisa: “If a pot was used to cook meat, one may not cook milk in it, and if he did, then we check if the pot gave meat taste to the milk. If a pot was used for terumah, one may not cook regular food in it, and if he did, then we check if the pot gave terumah taste to the food.” In the terumah case I understand how we check this: we have a kohein taste it. But in the meat and milk case, who can taste it? But now that Rabbi Yochanan said, “We rely on a non-Jewish chef,” here too, we rely on a non-Jewish chef.

חולין צז ע”א: אמר רבא: מריש הוה קא קשיא לי הא דתניא, קדרה שבשל בה בשר ־ לא יבשל בה חלב, ואם בשל ־ בנותן טעם, תרומה ־ לא יבשל בה חולין, ואם בשל ־ בנותן טעם, בשלמא תרומה ־ טעים לה כהן, אלא, בשר בחלב ־ מאן טעים ליה? השתא דאמר רבי יוחנן: סמכינן אקפילא ארמאה, הכא נמי ־ סמכינן אקפילא ארמאה.

A commercial bakery in Baltimore, certified by the Star-K, had been using oil bearing the hechsher of another well-known kosher agency. One day, the mashgiach of the bakery saw that the oil had a dairy designation, which means it was milchig (i.e. made on machinery that had been used for dairy within the past 24 hours). The company had been using this oil for a while when it was certified pareve, and no one had noticed until now that the hechsher had changed to dairy. Seemingly, this would make the bread milchig and therefore treif, because Chazal outlawed milchige bread lest someone come to eat it with meat (Pesachim 36a, brought in Yoreh Deah 97:1).

The mashgiach consulted Rav Moshe Heinemann, who advised, “Bring the bread to a Sephardi to taste whether there is any milk in it or not. Since the Mechaber is lenient to taste milchig bread, and the Rema is stringent, we can rely on a Sephardi tasting the bread.” They took the bread to a professional taster. He first washed out his mouth with ginger ale in order to rinse out the other flavors in his mouth and then tasted the bread. They asked him if he tasted anything other than bread and he said, “It has a creamy taste.”

Source: Mah Nomar, Hilchos Kashrus p. 26

[In Yoreh Deah 98:1, the Mechaber relies on a non-Jew to taste food and the Rema disagrees. But the Shach there says that even according to the Rema, a Jew may taste food when it is permitted in any case, for example when a radish was cut with a meat knife and the Jew tastes it to see if it has meat taste. Once the Jew determines that it has no meat taste, it may be eaten with milk.

In this case, why was the bread permitted in any case to the Sephardi? Possibly because the Mechaber in Siman 97 says that although bread containing milk is forbidden, “if it was a small amount that could be eaten all at once… it is permitted.” The Rema there says that we rely on this when we make milchig bread for Shavuos. Between the lines, there is a disagreement here on the meaning of “a small amount”. The Mechaber understands that even if there was a lot of bread baked, as long as the person is eating only a small amount it is allowed. The Rema holds that only a small amount may be baked, such as that baked for a Shavuos meal. Therefore, only a Sephardi, who follows the Mechaber, would be allowed to eat the small piece of bread necessary for the taste test. Had he noticed no milk taste, then even Ashkenazim would be allowed to eat the bread, as per the Shach above.

Another point of this story is that even though there was no actual milk in the bread, only oil made on dairy machinery, that was enough to forbid it to be eaten with meat, and thus forbid it entirely. This was confirmed by the taster who was able to sense the milk absorbed by the oil from the machinery.]

Chullin 66b: The Torah says, “This you may eat, from all that are in the water, anything that has fins and scales in the water, in the seas and rivers – those you may eat.” (Vayikra 11:9). This implies that the requirement of fins and scales applies only in seas and rivers. However, if the creature was born in a vessel or cistern, one may bend down and drink the water without removing the creatures.

חולין סו ע”ב: תאכלו מכל אשר במים מה ת״ל ־ שיכול, הואיל והתיר במפורש והתיר בסתם, מה כשהתיר במפורש לא התיר אלא בכלים, אף כשהתיר בסתם לא התיר אלא בכלים, מנין לרבות בורות שיחין ומערות ששוחה ושותה מהן ואינו נמנע? ת״ל תאכלו מכל אשר במים.

In Iyar 5764, creatures called copepods were discovered in all New York City water. The city’s Department of Environmental Protection had always been aware of them but didn’t bother to filter them out (as is done in other municipal water systems) because they don’t present a health risk. The copepods were visible to the naked eye as white objects, but without a magnifying glass, one could not tell that they were organisms (which had once been living but were now dead).

The Original Matirim

Rabbi Yisroel Belsky, Rabbi Shlomo Pearl, and Rabbi Elimelech Bluth ruled that they were permitted. Their reason was based on the Shach on Yoreh Deah 84:4, who says that if a creature was born in a cistern of water (in this case, the reservoir) and subsequently entered a vessel (the pipe), it is forbidden to eat if it leaves the vessel (comes out of the tap and onto the inside wall of your cup), but if it was born in a vessel and went into another vessel, it is permitted even if it comes out of the water. Here we assume the copepods were born in the pipes because of the principle of כאן נמצאו כאן היו (we assume that an object was always in its current location unless proven otherwise).

The copepods are killed by the chlorine, so the above assumption requires us to believe that they must have been born in the pipes before the chlorine was added. Rav Belsky checked with the Department of Environmental Protection and made sure the water enters a pipe before the chlorine is added. Also, he made sure that the water is in the pipe before the chlorine is added for a long enough time to allow for the copepods to hatch and grow to their observed size. Rabbi Yisroel Reisman and Rabbi Yisroel Pinchos Gornish concurred with Rav Belsky’s ruling.

The Osrim

Rabbi Feivel Cohen ruled that they were forbidden. Rabbi Hillel David also forbade drinking the water without a filter, but said that cooked food is mutar, and one may even cook food himself with unfiltered water. This is because the copepods fall apart, cease to be a “berya” (a complete organism) and become nullified. Although usually it is forbidden to intentionally nullify something treif, the Taz in Yoreh Deah 99:7 says that if your intent is merely to cook the food, and there happen to be insect parts in it, it’s allowed to nullify them.

Rabbi Hershel Shechter initially published a letter saying that these copepods are permitted because one cannot tell they are creatures with the naked eye. He assumed that just as one cannot recognize them when dead, one would not be able to recognize them when alive either. But when someone brought him a tray of water straight from the reservoir, full of wiggling specimens, he retracted his heter.

Later, a letter came out signed by Rabbi Dovid Feinstein, Rav Elyashiv and Rabbi Chaim Pinchas Scheinberg saying that the NYC tap water is forbidden because the copepods are visible when alive, and the reservoir is not considered a bor (cistern; rather, it is a river). Moreover, all of the original matirim, except for Rav Belsky, changed their position.

Rav Belsky’s conclusion

Even Rav Belsky, who remained lenient, changed his reason based on the emerging facts. His original heter was based on the assumption that the copepods were born in the pipe. But experts testified that they can’t be born in the pipe, since the water is rushing too fast. It must be that they are born in the reservoir, then enter the pipe and then come out of the tap. Even so, Rav Belsky permitted the water since the copepods die when the chlorine is added, and therefore we can rely on a combination of two factors:  

1. The reservoir has the status of a cistern, and there are Rishonim who hold that once dead, a creature remains permitted, even when separated from the water in the cistern.
2. Not every cup of tap water contains a copepod; it is only a miut hamatzui (a significant minority of cups).

Chullin 95b: Rabbi Shimon ben Elazar said: The first business deal one makes after building a house, having a baby or getting married is an omen of his future success, even though one may not act on this completely as a fortune teller would. Rabbi Elazar said: This is only true of he did three good or three bad deals in a row, thus creating a chazakah.

Rashi: One may not rely on this fortune telling, but still, if he failed in three deals, he should not go out for business too much, because this is an omen that he will be unsuccessful.

חולין צה ע”ב: תניא, רבי שמעון בן אלעזר אומר: בית תינוק ואשה, אף על פי שאין נחש יש סימן. אמר ר׳ אלעזר: והוא דאיתחזק תלתא זימני.

A young man named Yitzchak Ohevzion was interested in buying a certain apartment, but one of the other people living in the building came to him and said, “I would advise you not to buy it, because three deaths have taken place in that apartment. A young baby died, a man was murdered, and a woman died of an illness.”

Yitzchak went to Rabbi Chaim Kanievsky and asked him if he should worry about this. Reb Chaim thought for a moment, and then said, “Go and ask my father-in-law, Rav Elyashiv.” Rav Elyashiv said, “The house is not the cause of those deaths. You can buy the apartment and live in it.” The young man returned to Reb Chaim and told him the answer he had received.

Reb Chaim then said, “The Gemara in Chullin 95b says that we should worry about such things. ‘A house, a child and a wife, although one may not practice fortune telling, there is a sign. Rabbi Elazar said: This is only when there is a chazakah of three times.’ And see Rashi.”  But he added, “Now that my father-in-law said you don’t need to worry, you don’t need to worry. “

Source: Divrei Siach, Bemishnasam shel Rabboseinu Rav Yosef Shalom Elyashiv and Rav Chaim Kanievsky, published on Rav Elyashiv’s first yahrtzeit, p. 33.

[Based on this, we can understand the Gemara in Taanis 29b: “A Jew who has a dispute with a non-Jew should avoid going to court in Av, because it has bad mazal; he should try to have it in Adar, which has good mazal.” Seemingly this is “nichush” – fortune telling. But the answer is that if you are not totally rigid about it – you are merely trying to schedule it for Adar, but if necessary you will agree to go to court any time – there is no problem.]

Chullin 110a: Rami bar Dikuli from Pumbedisa came to Sura on Erev Yom Kippur. All the people took their udders and threw them out. He went and picked them up and ate them. They brought him before Rav Chisda, who asked him: “Why did you do that?” He said, “I am from the place of Rav Yehuda, who eats udders.”

 רמי בר תמרי, דהוא רמי בר דיקולי מפומבדיתא, איקלע לסורא במעלי יומא דכפורי, אפקינהו כולי עלמא לכחלינהו שדינהו, אזל איהו ־ נקטינהו אכלינהו, אייתוה לקמיה דרב חסדא, אמר ליה: אמאי תעביד הכי? אמר ליה: מאתרא דרב יהודה אנא, דאכיל. אמר ליה: ולית לך נותנין עליו חומרי המקום שיצא משם וחומרי המקום שהלך לשם? אמר ליה: חוץ לתחום אכלתינהו. ובמה טויתינהו? אמר ליה: בפורצניֹ. ודלמא מיין נסך הויא? אמר ליה: לאחר שנים עשר חדש הווֹ. ודלמא דגזל הוה? אמר ליה: יאוש בעלים הוה, דקדחו בהו חילפיֹ. חזייה דלא הוה מנח תפילין, אמר ליה: מאי טעמא לא מנחת תפילין? אמר ליה: חולי מעיין הוא, ואמר רב יהודה חולי מעיין ־ פטור מן התפיליןֹ.

Rabbi Chaim Shmulevitz often surprised his listeners with unusual sources for his principles of mussar.  A classic example of Rav Chaim’s mussar analyses of maamarei Chazal draws from the Gemara in Chullin 110a, which relates how Rami bar Dekuli of Pumbedisa was once visiting Sura on Erev Yom Kippur. When the townspeople threw away the udders of animals they had slaughtered for the Erev Yom Kippur feast, he collected them and ate them, in spite of the fact that there was a custom in Sura not to eat the udders of animals. Rami bar Dekuli was brought before Rav Chisda who asked him many questions about how, why and when he cooked and ate the udders. In the course of the discussion, Rav Chisda also asked why Rami bar Dekuli was not wearing tefillin, and he replied that he suffered from a stomach ailment.

Reb Chaim spent a long time explaining every single detail of the story. When he finished, the audience still could not work out the connection between the Gemara he was quoting and the rest of the shmuess. Finally, after a short pause, Reb Chaim continued:

“I am troubled by a very difficult question. Rav Chisda asked Rami bar Dekuli many questions, but one question he did not ask him: A Jew is suffering from a stomach ailment on Erev Yom Kippur. Why is he searching for discarded animal udders in garbage cans? In every Jewish home, people are sitting around the table eating the festive meal of Erev Yom Kippur. Why didn’t Rami bar Dekuli knock on somebody’s door? It seems that one does not ask such a question, for Rav Chisda understood very clearly the meaning of the words, אל תצטרך לבריות – do not take handouts from other people.”  

Source: The Rosh Yeshiva, p. 185; Sichos Mussar p. 29.

Chullin 106a: Not washing before a meal caused a Jew to eat pork. Rashi: There was a Jew who owned a restaurant serving kosher meat to Jews and neveilah meat to gentiles. Once a Jew came and did not wash his hands before eating, so the restaurant owner thought he was a gentile and served him pork.

חולין קו ע”א: מים הראשונים ־ האכילו בשר חזיר. רש”י: שהיה חנוני ישראל מוכר בשר שחוטה לישראל ומבשל ומאכילם וכשהעובד כוכבים בא בחנותו מאכילו נבלות ובא יהודי אחד לאכול ולא נטל ידיו וכסבור זה שעובד כוכבים הוא והאכילו בשר חזיר.

Someone once asked Rav Ovadiah Yosef: “If I can’t find another job, may I work in a treif restaurant, provided that I will not be cooking meat and milk together?”

The question hinges on whether there is any Rabbinic prohibition on working with treife food lest he come to eat it.

Rav Ovadiah quotes the Kesef Mishnah (Tumas Mes 1:2) who says that the reason why it’s forbidden to cook meat and milk together is out of fear that one might come to eat it. This goes into the category of gezeiros made by the Torah itself – similar to yichud. Yet, cooking a non-kosher animal’s meat with milk is allowed (Yoreh Deah 87:3). The prohibition is only on kosher meat (at least a kosher animal) and milk, because people are used to eating it each separately and may accidentally come to eat them together. This shows that there is no prohibition on working with treife food.

The Rashba (3:223) does say that the prohibition on doing business with forbidden food is because one might come to eat it. If so, “doing business” would include even an employee who does not own the business, because he too might come to eat. However, this is only the Rashba, who holds that doing business is a Rabbinic prohibition. According to most Rishonim, it is a D’oraisa, so “one might come to eat it” may not be the reason.

The Gemara in Chullin 106a seems to address this exact question. The Gemara quotes a saying, “Not washing before a meal caused a Jew to eat pork,” and Rashi tells the story of a Jew who owned a restaurant serving kosher meat to Jews and neveilah meat to gentiles. Once a Jew came and did not wash his hands before eating, so he thought the proprietor mistook him for a gentile and served him pork. The Maharsha asks: why did Rashi begin by saying that this Jew served neveilah to gentiles, and then end by saying that he served pork to this customer? He explains that the Jew usually sold neveilah meat – not pork – because one may not deliberately do business with non-kosher, so he sold only the neveilah that resulted from mistakes in shechitah. It was only this time that he happened to have some pork on hand. So we see that the Maharsha was assuming that this proprietor was an observant Jew. If so, we see that it’s okay for a Jew to cook and serve non-kosher food to gentiles.

However, the Beis Yosef (end of 117) argues that the restaurant owner may have been a non-observant Jew, and besides, this story is no proof because, as the Midrash (Bamidbar 20:21) says, the story took place during the period of Greek persecution. The Jew sold pork deliberately in order to hide his Jewish identity, and the hand-washing was a secret cue for the Jews to show him they were Jewish, so that he should serve them kosher meat.

In the end, Rav Ovadiah paskened that this unemployed person should try his hardest to find a different job, in order to follow the stricter opinion. But if there was no other way, he could rely on the Maharsha and take the job in the treif restaurant.  

Chullin 93a: Cheilev that is covered by the meat is permitted. Rashi: Forbidden fat that is on the flanks under the kidneys and visible on the high part of the flanks, and then disappears under the meat, red and spreading under the meat throughout the flanks. As soon as the meat covers it, it is permitted. And when that meat ends below [at the animal’s belly], a thick, white membrane protrudes… under that thick membrane there is cheilev, and some hold that that cheilev is forbidden, because that membrane is not considered “a covering of meat” since it is very thin. But in Germany they permit it. And to me as well, it seems that it is a complete covering.

חולין צג ע”א: אמר רבי אבא אמר רב יהודה אמר שמואל: חלב שהבשר חופה אותו מותר. פירש”י חלב שהבשר חופה אותו ־ חלב שעל הכסלים שתחת הכליות ונראה בגובה הכסלים ואח״כ נבלע תחת הבשר אדום דק ומתפשט תחת אותו בשר בכל הכסלים ומשהבשר חופהו מותר וכשכלה למטה אותו בשר יוצא ממנו קרום עב ולבן, לבד קרום דק וקלוש המתפשט בכל הכסלים שאסור משום חלב כדלקמן, ותחת אותו קרום עב יש חלב ויש שנוהגים איסור באותו חלב לפי שאותו קרום אינו חשוב חפוי בשר שדק הוא אבל בארץ אשכנז נוהגין בו היתר וגם בעיני נראה דחפוי גמור הוא.

Rabbi Yisroel Belsky was once asked to inspect a traditionally reliable kosher restaurant, after someone suggested that they were serving cuts of lamb meat with the cheilev still attached. This establishment would buy the freshest meat and perform their own nikkur, and they employed a mashgiach with many years of experience. “The owner of the restaurant, the butcher, and the mashgiach each inspected the lambs they showed me,” Rav Belsky related, “and were at a loss to explain why anyone would suggest there was any cheilev. Now, all lambs have cheilev attached to the navel, and even though that piece of meat is very tasty, there is no way to clean off the cheilev, and it must simply be cut off and discarded. Unfortunately for this restaurant, they had never identified this piece of cheilev for they mistakenly looked at the meat upside-down, and thought the cheilev was simply a piece of permitted fat. The allegation was indeed true.”

Source: Halachic Responsa From the Desk of Harav Yisroel Belsky, p. 191

Chullin 59a: The characteristics of a kosher grasshopper are that it has four legs, four wings, jumping legs, and its wings cover most of its body. Rav Yehuda said in the name of Rav: This means most of the length of the body. Some say: Most of the circumference. Rav Papa said: Therefore we require them to cover most of the length and most of the circumference.

חולין נט ע”א: ובחגבים: כל שיש לו ארבע רגלים, וארבע כנפים, וקרצולים, וכנפיו חופין את רובו. ובדף סה ע”ב: מאי רובו? אמר רב יהודה אמר רב: רוב ארכו, ואמרי לה: רוב הקיפוֹ אמר רב פפא: הלכך, בעינן רוב ארכו, ובעינן רוב הקיפו.

In approximately 2001, Rabbi Chaim Kanievsky was learning Maseches Chullin and reached the sugyah relating to grasshoppers.  Rav Chaim realized that he needed to see a grasshopper to better understand the Gemara, and asked his daughter to bring him one. She tried, but reported to her father that she failed to find one. He went back to the sugyah, and lo and behold, a grasshopper came hopping through the window, landing on his Gemara. After examining it, he let it go. As he continued through the sugyah, he realized that he needed to study the hind legs a bit more, but the grasshopper was long gone. Before closing his Gemara, a second grasshopper hopped in and on to his Gemara, giving him a chance to study its hind legs in detail.

The story spread quickly. Some time later, a rov giving a shiur in Bnei Brak criticized the tales people tell about gedolim, explaining that the stories cannot all be true, and sound silly. As a case in point, he brought the story of Rav Chaim and the grasshoppers. After the shiur, the maggid shiur went home and found his house infested with grasshoppers. He tried for three days to rid his home of the insects, but could not.  Someone suggested that he go to Rav Chaim and ask for mechilah. The rov approached Rav Chaim and told him what had happened. Rav Chaim laughed, saying that he did not need his mechilah at all, as the grasshoppers could have come to anybody (after all, the window was open!), and he was certainly mochel him if he needed it. The rov went home – and the grasshoppers were gone!

The above story was printed in a certain sefer, about which Rabbi Yaakov Galinsky quipped, “I would say I don’t believe it, but I am afraid a plague of copies of that sefer will occupy my house.”

Source: https://matzav.com/grasshopper-nissim-with-rav-chaim-kanievsky/

Chullin 27b: Animals were created from earth, so they need both the esophagus and windpipe cut. Fish were created from the water, so they don’t require any shechitah. Birds were created from the mud, so they only need one tube cut.

Rema Yoreh Deah 13:1: It is allowed to cut a piece off a live fish and eat it, but it is forbidden to eat a whole fish live because of the prohibition, “Do not make yourself disgusting.”

חולין כז ע”ב: דרש עובר גלילאה: בהמה שנבראת מן היבשה ־ הכשרה בשני סימנים, דגים שנבראו מן המים ־ הכשירן בולא כלום, עוף שנברא מן הרקק ־ הכשרו בסימן אחד.

יורה דעה יג,א בהמה חיה ועוף טעונין שחיטה דגים וחגבים אין טעונין שחיטה: הגה ומותר לאוכלם מתים, או לחתוך מהם אבר ולאכלו, אבל אסור לאכלן חיים משום בל תשקצו.

The Hamodia newspaper recently interviewed Rabbi Boruch Cohn, a rebbi in Lakewood who enjoys fishing in local lakes and streams. Their first question was, “Fishing is not known to be a popular downtime activity in our circles. Is there a good reason for this?”

Rabbi Cohn replied, “I don’t have a clear answer to this one, but it might be that people don’t have the time or perseverance to fish; it’s not a pastime for those who want instant gratification! Another reason could be that they’re prone to associate it with hunting, which is assur. When I was thinking of taking up fishing, I discussed the issue with Dayan Yaakov Posen, shlita, of Washington Heights, where I grew up. He advised me that the issur of tzaar baalei chaim (causing affliction to living things) does not apply to fish and gave me an enthusiastic go-ahead. I have since spoken to several Lakewood poskim on this matter, and they are in full agreement with Dayan Posen.” 

(Hamodia, July 8, 2020, Community p. 25)

[Actually, the problem with hunting, according to the Noda Beyehuda (Tinyana YD 10, brought in Pischei Teshuva YD 28:10), is not tzaar baalei chaim, for two reasons:

1) People use the skins, and there is no prohibition on tzaar baalei chaim when the animal is used for the needs of man. The source for this is Piskei Hatosafos Avodah Zarah 11a, explaining why it is allowed to cut the hooves of the king’s horses after the king dies.  

2) There is no prohibition of tzaar baalei chaim when you are killing the animal, only when you are keeping it alive and suffering. This is based on Chullin 7b, where Rabbi Pinchus ben Yair reprimanded Rebbi for owning dangerous white mules. Rebbi proposed cutting their hooves, but Rabbi Pinchus responded that this would be tzaar baalei chaim. Then Rebbi proposed killing them, to which Rabbi Pinchus responded that it would be bal tashchis – wastefulness. From this exchange we see that killing can never be tzaar baalei chaim.

Rather, the problem with hunting is that killing animals for sport is cruelty. We are enjoined to feel that “His mercies are upon all His creatures” and that is why we don’t say bless someone who buys a new leather garment that he should wear it out and buy a new one (Rema Orach Chaim 223:6). Therefore hunting, unless done for a living, may not be strictly forbidden but it does inculcate a bad midah and is not the right thing for a Jew to do.

Furthermore, going out to the forests where the wild animals live is dangerous, and one is forbidden to place his life in danger. Esav was an expert hunter, yet he testified on himself, “Behold I am going to die,” and the Ramban explains that he was likely to die in his father’s lifetime, so he did not need the birthright. One who hunts to make a living is permitted to risk his life, as it says, “He risks his life for it” (Devarim 24:15). But if he doesn’t need the money, it is forbidden.

According to this, it would seem that fishing for sport should exemplify the same bad midah of cruelty as hunting for sport. Tzaar baalei chaim may not apply, but the midos argument still would.

The Noda Biyehuda’s contention that there is no prohibition of tzaar baalei chaim when killing the animal would seem to be against the Sefer Hachinuch 451, who says that the reason for slaughtering at the neck with a perfectly sharp knife is in order to minimize tzaar baalei chaim. According to the Chinuch, we could prove that the prohibition does not apply to fish from the very fact that no shechitah is required.

The nafka minah between the Noda Biyehuda and the Chinuch would be in the question of whether one may make a fish suffer when not killing it. According to the Noda Biyehuda it is forbidden, while according to the Chinuch it is permitted.

Rabbi Menashe Klein (Mishneh Halachos 6:216) was asked whether someone who has an aquarium in his house is obligated to feed the fish before eating a meal. The questioner had brought proof from the fact that one may cut a piece off a live fish, that there is no prohibition of tzaar baalei chaim on fish. R’ Menashe counters that perhaps there really is tzaar baalei chaim on fish, yet eating from a live fish is allowed because the prohibition on causing pain doesn’t apply when using the animal for human needs. We see, for example, that one may cut off and eat a piece of a ben pekuah (a live baby found inside a slaughtered cow) even though it is alive and certainly feels pain (Taz YD 13:3).  

Then he brings a proof that there is indeed tzaar baalei chaim on fish, from the fact that one may not harness two different kinds of fish to his boat (Bava Kama 55a). The prohibition on harnessing two different species is because of tzaar baalei chaim, since an animal does not like to work together with a different kind of animal (Chinuch 550). If this applies to fish, then clearly there is tzaar baalei chaim on fish. He concludes that one must feed his fish before eating a meal (and therefore recommends not keeping an aquarium, lest one transgress this prohibition when eating away from home).

Thus there appears to be an internal contradiction in the Chinuch. If fish have tzaar baalei chaim, then why is it allowed to eat them without shechitah? And you cannot answer, as R’ Menashe Klein does, that for the purpose of man there is no prohibition, because the Chinuch says that even at the time of shechitah we try to minimize pain.

Rather, the answer is probably that the Chinuch’s approach is merely to suggest reasons for mitzvos (often, as in these two cases, more than one reason for each mitzvah), without being particular that everything he says leads to the same halachic conclusions.]   

Chullin 111a: Perhaps the reason it was allowed to cook the heart and liver was because they dipped them in boiling water, so that the blood was cooked inside the meat and was thus unable to come out. This is similar to the story of Rav Huna, who ate unsalted meat dipped in vinegar, and Rav Nachman, who ate unsalted meat dipped in boiling water.

חולין קיא ע”א אי נמי מיחלט הוה חליט ליה מעיקרא כי הא דרב הונא חלטי ליה בחלא ורב נחמן חלטי ליה ברותחין. וכתב הרי”ף שהגאונים גזרו על זה כיון דאין אנו בקיאין. והערוך השולחן בסימן ס”ט סקס”ח ביאר החשש של הגאונים ואח”כ כתב ומ”מ דעה ראשונה עיקר להלכה ולכן לצורך מותר.

Rabbi Moshe Feinstein was asked by his grandson, Rabbi Mordechai Tendler, how to prepare meat for a person with a heart condition and high blood pressure, whose doctor told him to avoid salt. R’ Moshe said, “There are two ways: the first is to have a separate pot, cut the meat up into small pieces and drop them into vigorously boiling water. Although we don’t usually use this as a method of kashering meat, because the Gaonim say we are not expert in using it, in this case one can be lenient.

“The second way is to use another type of salt, such as ammonium chloride or potassium chloride. The question about this is only whether such salt works to remove blood. If it is a naturally occurring salt, it definitely works. For we see that Sodom salt has different components from our salt, since it causes blindness, yet it works for kashering. But if it does not occur naturally, then we don’t know if it removes blood.”

Rabbi Tendler suggested that the person should do both: first salt with another type of salt, and then drop into boiling water. This way, if the salt doesn’t work, there is at least a chance that the boiling will work. Reb Moshe said perhaps, but one need not do both. He concluded that the first idea would be the best one to use.

Source: Mesores Moshe, v. 1, p. 209

Chullin 111a: Rabbah bar Rav Huna was eating at Rabbah bar Rav Nachman’s house. He noticed that the liver had an artery that was saturated with blood. He said to them, “Why did you do that?” They said: “What should we have done?” He said, “Tear it crisscross and put the torn side down while you roast it.”

קיא ע”א: אשכח ההוא כבדא דהוה בה סמפונא דבליעא דמא, אמר להו אמאי עבדיתו הכי? אמרו ליה: אלא היכי נעביד? אמר להו: קרעו שתי וערב וחיתוכא לתחת.

שו”ע יו”ד ע”ג ס”א: הכבד יש בו ריבוי דם לפיכך לכתחלה אין לו תקנה לבשלו ע״י מליחה אלא קורעו שתי וערב ומניח חיתוכו למטה וצולהו (שיהא ראוי לאכילה) (או״ה נתיב ט״ו) ואחר כך יכול לבשלו… ובדיעבד מותר אם נתתבשל לבדו בקדירה (בלא צלייה) אבל הקדירה אסורה שפולטת ואינה בולעת ויש מי שאוסר. רמ”א: וכן נוהגין לאסור הכל.

A man came to Rabbi Avrohom Pam and said, “My wife bought a whole chicken and didn’t realize that the liver was packed inside. She cooked it in soup, and then served the chicken on china plates. We have no problem throwing out the chicken and kashering the soup pot, but is there any heter to save the china plates?”

Rav Pam replied, “The Shach (73:8) says that although we hold like the opinion that liver needs to be roasted, and therefore if it was cooked one may not eat it, still the plate on which the liver was served after cooking does not become forbidden. The Pri Megadim asks why not – doesn’t pouring from a kli rishon cook the outer layer of the plate? Also, the Shach himself in 74 and 105 holds that a hot piece of solid food (דבר גוש) can transmit taste even when in a kli sheini.

The Chavos Daas answers:

ולענ”ד לא קשיא מידי דהא כתב הש”ך בסימן ק”ה ס”ק י”ח דחתיכה שנאסרה מחמת דם הוי כאיסור בלוע, ושם בס”ק כ”א שאינו מבליע כדי קליפה רק מגוף הדבר אבל מאיסור בלוע אינו בולע אפילו בשמן וכ”ש דם דכחוש הוא ודאי דאינו יוצא מחתיכה בלא רוטב.

“When the solid piece of hot food being placed on the plate is not forbidden on its own, only because of something else that got absorbed in it, then it does not transmit taste to the plate through pouring. And a piece of meat that is forbidden because it contains blood is like any other piece that has something forbidden absorbed in it.”

Therefore, said Rav Pam, the chicken, which contains blood from the liver cooked with it, will not forbid the plate.

[What is puzzling is that although Rav Pam was certainly correct about the chicken, which is only forbidden because it absorbed from the liver, the Chavos Daas says this even regarding the liver itself. He cites as his source the Shach in 105, but the Shach there (105:18) clarifies that he says this only regarding blood absorbed in the meat that came from another source, whereas blood from that piece of meat itself – i.e. if it was not salted properly – would forbid other pieces or plates. Seemingly this liver, which was cooked without roasting, is in that category.

The answer may lie in the second Shach (105:21) quoted by the Chavos Daas. There he says that even though usually fatty tastes absorbed in one dry piece can travel to another dry piece through touch, if the bottom piece (or plate) is cold, it does not travel. If so, possibly even blood that originated within the liver itself cannot travel to the plate under it.

The only problem is that the Chavos Daas says that blood is a כל שכן from fatty tastes, and according to the above explanation it is not really a כל שכן, since here the blood originated in the meat and is therefore worse, in one aspect, than fatty taste that came from elsewhere.]

Source: Rabbi Yisroel Reisman, tape on YD 73:6.