1) EATING TWO HALVES OF AN "EVER MIN HA'CHAI"
OPINIONS: The Gemara discusses cases in which one "splits" an Ever Min ha'Chai and eats it. Everyone agrees that when one splits an Ever Min ha'Chai outside of his mouth and then eats it, he is Chayav. When he splits it inside of his mouth, Rebbi Yochanan says that he is Patur and Reish Lakish says that he is Chayav.
What exactly does the Gemara mean by one who "splits" an Ever Min ha'Chai?
(a) RASHI (DH Chalko and DH Mahu) explains that the Gemara is discussing a case of an Ever Min ha'Chai that is exactly one k'Zayis in size, and the person splits it into two parts and eats them separately, but within the time period of "Kedei Achilas Pras." Although this is considered a single act of eating with regard to other prohibitions, with regard to Ever Min ha'Chai it is not considered a single act of eating.
According to Rashi's explanation, everyone would agree that one who eats two halves of an Ever Min ha'Chai in one swallow is Chayav.
(b) TOSFOS (DH Chalko) questions Rashi's explanation. The Gemara asks that according to Reish Lakish, when is one ever Chayav for eating Ever Min ha'Chai? According to Rashi, the Gemara is asking that one cannot eat a full k'Zayis at once, and thus whenever one eats Ever Min ha'Chai he eats it in pieces less than a k'Zayis. Why, though, is it so difficult to find a case in which one is Chayav? It is not difficult to swallow a chewed mass of one k'Zayis at once!
Tosfos therefore explains that the Gemara is discussing a case in which the two halves are swallowed at once. With regard to the Isur of Ever Min ha'Chai, the Torah requires that the Ever be placed into the mouth (according to Rebbi Yochanan) or swallowed (according to Reish Lakish) as a single, unbroken k'Zayis. According to Reish Lakish, one is not Chayav unless he swallows an entire, solid chunk of a k'Zayis of Ever Min ha'Chai. Accordingly, the Gemara's question on Reish Lakish is understandable: how does one ever transgress the Isur of Ever Min ha'Chai if he must swallow a solid chunk of k'Zayis at one time? This indeed is extremely difficult to do. (Z. Wainstein)
2) HALACHAH: PLACING MEAT AND MILK ON THE SAME TABLE
QUESTIONS: The Mishnah teaches that not only is one forbidden to eat meat and milk together, but one is also forbidden to place them together on the same table. RASHI (DH v'Asur) explains that the Rabanan prohibited placing them on the same table lest one come to eat them after they have touched each other (while still hot) and absorbed each other's taste.
(a) Why does Rashi explain that the concern is that one might eat the meat or milk after they touched each other and absorbed each other's taste? Even if they did not touch each other, one is forbidden to eat them together! Rashi should explain simply that the Rabanan prohibited placing them on the same table lest one come to eat them together.
(b) Why is there such a strong concern that just because the meat and milk are placed on the same table, they might be eaten together? Why will a person not remember that eating meat and milk together is forbidden, the same way he remembers that eating them together is forbidden when they are in the same room (such as the kitchen)?
(a) The MAHARAM explains why Rashi writes that placing meat and milk on the same table is prohibited because of the concern that one might eat meat and milk that have been cooked together. The prohibition against placing meat and milk on the same table is an Isur d'Rabanan. Eating meat and milk together, when the meat and milk were not cooked together, is an Isur d'Rabanan (108a; see SHULCHAN ARUCH YD 87:1). The Rabanan do not make a "Gezeirah l'Gezeirah," a decree to safeguard another decree. They only institute a Gezeirah in order to safeguard an Isur d'Oraisa. Since they instituted an Isur against placing meat and milk on the same table, it must be that they were trying to prevent an Isur d'Oraisa from being transgressed. Therefore, Rashi explains that the reason for the decree is to prevent meat and milk from being cooked together and then eaten, which is an Isur d'Oraisa. (See also MAHARAM SHIF.)
(b) The RAN (32b of the pages of the Rif) writes that the Rabanan treat the Isur of meat and milk more strictly than they treat other prohibitions. Since meat is permitted by itself and milk is permitted by itself, people are not so careful to keep away from them and thus are more prone to come to eat them together. Therefore, the Rabanan prohibited bringing them to the same table.
The Ran rules, based on this approach, that one is permitted to eat at a table on which other forms of forbidden foods are placed. One may eat at the same table at which a Nochri is drinking his wine and eating his non-Kosher food. Since a Jew is always careful to stay far away from such foods, there is no concern that he might come to eat them when they are resting on the same table.
The Ran uses this approach to explain the ruling of Rav Kahana in Pesachim (76b) that bread cooked in the same oven as roasted meat may not be eaten with dairy food. The Ran writes that this Halachah applies even according to the opinion that "Reicha Lav Milsa," the aroma of a substance is considered insignificant and does not give another food the status of the food of origin. Nevertheless, with regard to the Isur of meat and milk the Rabanan were more stringent because each one is permitted by itself, and therefore the Rabanan prohibited eating with milk a loaf of bread that absorbed the aroma of meat.
The SHACH (YD 88:2) rules, based on the words of the Ran, that even though meat and milk may not be brought to the same table, one is permitted to bring meat of Neveilah to the same table as Kosher meat. This is because a Jew is always careful to refrain from eating Neveilah. The PRI TO'AR, however, writes that a forbidden food that is not readily recognizable as forbidden (such as Chelev, fruits of Orlah, untithed fruits) may not be placed on the same table at which one is eating, because one might forget that the food is forbidden and eat it. (The MA'ADANEI HA'SHULCHAN 88:2 suggests that if it is not feasible to remove the forbidden food from the table, one may place a note on the forbidden food as a reminder that it is forbidden.)
However, the Shach adds that the Ran's logic does not permit a Jew to eat at the same table as a Nochri during Pesach. Even though a Jew is very careful to refrain from Chametz during Pesach, the Rabanan were extra cautious with regard to the Isur of Chametz and they prohibited eating at a table at which a Nochri is eating Chametz.
The Shach writes further that the Ran's logic does not apply to forbidden bread. Since bread is a staple food (as the verse states in Devarim 8:3), a person is more likely to forget about the Isur and eat the bread. Therefore, one may not eat at a table on which forbidden bread is placed, as the Gemara later (104b) teaches. (The Gemara there says that had the Isur of Chalah in Chutz la'Aretz been an Isur d'Oraisa and not d'Rabanan, it would have been forbidden to bring it to a table at which a non-Kohen is eating.) (See Insights to Chulin 107:5
This Halachah has other practical ramifications. Is a person permitted to prepare or work with dairy food within six hours after he ate meat? Similarly, is a person who ate meat within the past six hours permitted to sit together with a person who is now eating a dairy food? Is there a concern that the person will forget that he ate meat and taste the dairy food?
The PRI MEGADIM (Mishbetzos Zahav YD 88:2) cites the BEIS YAKOV (#12) who rules that one who ate meat within six hours may not sit with a person who is eating cheese, lest his friend give him some cheese to eat. However, if the one eating the cheese knows that his friend ate meat within six hours, then they may sit together. The Pri Megadim concludes, however, that we do not find that people are stringent in this matter. Similarly, the YAD EFRAIM (88:2) is lenient and permits the two to sit together. The Yad Efraim adds that it is also the commonly accepted practice to prepare dairy food even though one ate meat within the past six hours. However, if the dairy food is one that is commonly tasted during preparation, one should take appropriate precautions to avoid eating the dairy food while preparing it. (D. BLOOM, Y. SHAW)
3) HALACHAH: FISH WITH MILK
OPINIONS: The Mishnah teaches that one is prohibited to cook all types of meat together with milk, except for the meat of fish and locusts. Rav Ashi in the Gemara later (104a) explains that when the Mishnah says that one is not prohibited to cook fish with milk, it means that it is not prohibited mid'Oraisa or mid'Rabanan. The Halachah follows the view of Rav Ashi (SHULCHAN ARUCH YD 87:3), and one may cook fish with milk even l'Chatchilah.
Although there is no prohibition against cooking fish with milk, is there any reason to refrain from eating such a mixture because of health concerns? The SHULCHAN ARUCH (OC 173:2) prohibits eating fish together with meat, because the Gemara in Pesachim (76b) teaches that such a mixture is harmful to one's health.
(a) The BEIS YOSEF (YD 87, DH Dagim) writes that although one is not prohibited to cook fish with milk, one should not eat fish that was cooked with milk because it is harmful to one's health.
(b) The DARCHEI MOSHE writes that there is no source that eating fish with milk is harmful. He writes that "it seems that the Beis Yosef is mixing meat with milk" when he writes that fish may not be eaten with milk, when in fact it may not be eaten with meat. Accordingly, the SHACH and TAZ suggest that there is a printing mistake in the Beis Yosef, and the word "milk" should read "meat."
The PISCHEI TESHUVAH (87:9), however, quotes the BEIS LECHEM YEHUDAH who writes that he discussed with doctors the issue of whether eating fish with milk is harmful, and he discovered that the medical consensus is that eating fish cooked with milk is harmful, while eating fish fried with butter or milk fat is not harmful. The PRI MEGADIM (Mishbetzos Zahav 87:3) also writes that he researched the issue and found that eating fish cooked with milk is harmful, and he concludes that one should refrain from eating fish with milk, but one may eat fish with butter. The TESHUVOS ADNEI PAZ (#42) rules that even b'Di'eved one may not eat fish with milk. (The Pischei Teshuvah quotes the CHASAM SOFER who argues with these medical findings and says that there is no danger involved with eating fish and milk.)
The Pischei Teshuvah also quotes RABEINU BACHYE (to Shemos 23:19) who writes that the view of the doctors is that fish and cheese cooked together are harmful to one's health. The Pischei Teshuvah concludes that today, when everyone cooks fish with milk, it is permitted ("Keivan d'Dashu Bah Rabim"). This is also the view of the YAD EFRAIM.
The KAF HA'CHAYIM
also quotes the differing opinions. He concludes that since the question is whether such a food is harmful or not, it is possible that in one place the food is harmful, and in another place it is not. Therefore, in a place where the practice is not to eat fish with milk, one should be stringent and refrain from eating such a mixture. In addition, in such a place one should wash his hands between fish and milk, and do Kinu'ach (clean out his mouth by eating a piece of bread or any other food that does not cling to the mouth) and Hadachah (rinse out his mouth with water or wine; see Insights to Chulin 105:1
The common practice today is to be lenient with regard to eating fish with milk. However, some are stringent and refrain from eating fish with milk.