Siman 96

We say in the Gemara (Chullin 111b): A radish that one cut with a knife that one used to cut meat, it is forbidden to eat it with kutach. And it is not similar to fish that were served on a plate, which are permitted to be eaten with kutach as was written in siman 95, for that is a case of "flavor that is the result of flavor," because a knife sometimes has fat congealed upon its surface and it is not noticeable, and when one cuts with the radish, it imparts flavor that comes from the substance itself. And furthermore, because of its sharpness, it absorbs more than hot fish, and through the pressure of the knife, the knife emits and the radish absorbs [Rashi].

And there is a difference between the two reasons, for according to the reason of the congealed fat upon its surface, it is forbidden even if the knife is not ben yomo, and it does not constitute a flavor that imparts a defect, since there is no absorbed flavor here but rather the flavor itself. But according to the second reason, that it absorbs due to the sharpness, the prohibition only applies if it is ben yomo. Our teacher, the Beit Yosef, wrote similarly in section 1, and this is his wording: A radish or a beet that one cut with a meat knife that is ben yomo, or that is not wiped clean, it is forbidden to eat them with milk until one removes from the place of the cut a "kedei netilat makom," which is the thickness of a finger, or until one tastes it and there is no meat flavor in it, in which case it is permitted with rinsing. Thus far his words. And it is similarly explained from the wording of the Rambam, chapter 9, law 24, that it deals with a ben yomo, as he wrote: A knife with which one cut roasted meat, and then went back and cut with it a radish or similar sharp items, it is forbidden to eat them with kutach. Thus far his words. This implies explicitly that immediately after one cut roasted meat with it, meaning hot meat, and then afterwards cut a radish with it, it is forbidden to eat it with kutach. And from the wording of the Shas itself one can be precise in this way, since it says "a radish that one cut with a knife with which one cut meat etc.," and it does not say "with a meat knife," we learn from this that the intention is that the cutting of the meat was also recent, to exclude when it was not ben yomo. And the Rambam did not need to explain that when there is fat upon the knife it is forbidden even if it is not ben yomo, for this is simple and does not need to be explained.

And one should not ask: Behold, the Sages, of blessed memory, said at the end of the chapter "Ein Ma'amidin" that regarding a sharp substance there is no distinction between that which is "ben yomo" and that which is "eino ben yomo," for they said there that a piece of an idolater's asafoetida is forbidden for eating—what is the reason? Because they cut it with a knife, and even though that which imparts a flavor for the worse is permitted, and most vessels are not "benei yoman," nevertheless, due to the sharpness of the asafoetida, it sweetens the fat within the knife and it is like imparting a flavor for the better and it forbids (Avodah Zarah 39a); behold, it is explicit that a sharp substance makes that which is "eino ben yomo" like that which is "ben yomo." The Rishonim wrote that this is not the case with every sharp substance, but only with asafoetida which is very sharp [Tosafot there, and the Rosh, in the name of the Maharam of Rothenburg], for it is not human food at all, only occasionally they mix a little of it into the food [Bartenura chapter 1 of Tevul Yom mishnah 5 and Tosafot Yom Tov], and its smell is foul (Mishnah Uktzin 3:5) and its primary use is for medicine (Shabbat 140a), and it has much heat, and it is not similar to a radish and other sharp foods whose sharpness only suffices to extract the absorbed flavor from within the vessel and the food, but not to make that which is "eino ben yomo" like that which is "ben yomo," and this is the opinion of several of our teachers:

However, there are some of our teachers who wrote that hiltit and all sharp things share the same law, and they equate those that are not ben yomo. This is what our teacher, the Beit Yosef, wrote there, that there are those who say the law is the same for one that is not ben yomo if it is wiped clean. Thus far his words. This is because the sharpness sweetens, making that which is not ben yomo like that which is ben yomo. This is the opinion of the author of Sefer HaTerumah, as the Tur wrote, and most of the poskim among the great Acharonim adopted this as the halacha. Also, in the days of the Rishonim, they would rule thus, as the Rosh wrote there. One should not include the leniency of the first opinion except in a case of great need and significant loss [and the Tosafot in Chullin 112a were in doubt regarding this, see there in the heading beginning "Agav," and I am surprised that I did not find the law of a grain of hiltit in the Rambam]:

How much a sharp item forbids: it has already been explained that it forbids a kedei netilah, which is the thickness of a finger. And even though when one cuts with a milky knife that is not ben yomo it suffices with a kelipah, as is written in siman 94, section 30, and there it is regarding hot meat, and it stands to reason that sharpness would not have more power than heat, it can be said that here, since it is ben yomo, it emits more. And even according to those who are stringent even when it is not ben yomo as has been written, this is because the sharpness sweetens [the fat] and it becomes like ben yomo, and this power does not belong to heat. Furthermore, there, to forbid the meat, a kelipah suffices; however here, where we are not forbidding the radish but only that he should not eat it with milk, we were stringent to require netilat makom [Bach]. And in truth, there are some of the poskim who even here only require a kelipah, and this is the opinion of the Tur who wrote: a radish etc. until he peels the place of the cut etc., see there. Nevertheless, the opinion of the Ra'avad and many of the poskim agreed with him, since the Shas says plainly "it is forbidden to eat it with kutach," for if it were only a kedei kelipah, the Shas would not have said plainly "it is forbidden." And in truth, because of this phrasing, the Rashba, of blessed memory, wrote that all of it is forbidden, as the Tur wrote in his name, and he brought a proof for his words, for behold, regarding a piece of hiltit we forbid all of it as is written in siman 114 [via the Beit Yosef]. However, from there there is no proof, because the pieces are small and it is impossible to know in which place they cut it, therefore they forbade all of it; but here, a kelipah [the Rosh there] or a netilah suffices. And so is the primary ruling, that a sharp item forbids a kedei netilah, for so our teachers the authors of the Shulchan Aruch decided as the primary ruling. However, ab initio we are concerned for the opinion that forbids all of it, as will be explained. And there is no difference regarding a sharp item between a forbidden substance or from meat to milk and from milk to meat.

And that which he wrote, "or if he tastes it and it does not have the taste of meat," then it is permitted with rinsing. Thus far his words. Although it will be explained in siman 98 that we do not rely on tasting, it can be said that this refers to the tasting of a non-Jew, but here we can rely on the tasting of an Israelite. However, the great Acharonim wrote that in this case as well we do not rely on tasting [Taz subsection 2, and Shach subsection 5], and this is ab initio, but ex post facto, if they tasted it and it has no taste of meat, and they cooked it in milk, it is permitted [ibid.]. And know that silka is beets, and this species is not known in our lands, and from the language it implies that this is also sharp like a radish; however, some have written that it has no sharpness at all but rather it has a drawing power and therefore its law is like a sharp thing [Pri Chadash subsection 1], and according to this, a new law is innovated for us: if a certain type of food is known to us to have a drawing power, it has the law of a sharp thing [see Pri Megadim subsection 1, and the reason of drawing power was written by the Rashba in Torat HaBayit].

If one cut the radish with a meat knife and did not cut from it a netilah-sized piece, and also did not taste it, and cooked it in milk, one requires sixty against the place of the netilah. And if he does not know how to estimate the place of the netilah, he should estimate sixty against that which the knife touched when he knows with certainty up to which place of the knife it touched. And if he does not know with certainty, we say that presumably he drew the entire knife through, and one requires sixty against the entire knife except for the handle [Shach, and Taz subsection 4]. However, if he cut the radish into very fine pieces, one must estimate sixty against the entire radish, for every piece of it is forbidden up to the size of a netilah; but this is only when the entire radish is less than the knife, for if it is not so, sixty against the knife is sufficient, for there is no meat flavor beyond the draw of the knife.

Just as the law regarding a knife with which one cut meat in terms of eating milk with it, so too is the law regarding a forbidden knife when one cut a radish or another sharp item with it, that it becomes forbidden to the extent of a k'dei netilah; and if he cut it into very fine pieces, one requires sixty times against the whole of it. However, according to our position that we maintain "a piece becomes a carcass" (chatichah na'aseit nevelah) regarding all prohibitions, as written in siman 92 (Shulchan Aruch Yoreh Deah 92), there is a difference between a radish cut with a meat knife and a radish cut with a forbidden knife. For with a meat knife, one does not require more than sixty times against the knife in any case, as has been written. But with a forbidden knife, if the place of the netilah is more than the length of the knife, one specifically requires sixty times against the place of the netilah; and certainly when he cut them into very fine pieces, one requires sixty times against the whole of it, for the whole of it becomes a carcass. There is one who wishes to be stringent that even when he cut in one place where it requires netilat makom, that nevertheless we should require sixty times against the whole of it, because the whole of it becomes a carcass. These are astonishing words, for beyond the extent of netilah it does not become a carcass; and even if his intention is when he cooked it, and due to the reason of "attached prohibition" (issur davuk) when there is not in the radish itself sixty times against the place of the netilah, it is also not so, for in this the law of attached prohibition is not applicable. Since the place of the netilah is not forbidden in its own right but rather due to absorbed prohibition, this is not a recognizable and distinct prohibition such that it would be applicable to say "attached prohibition" regarding it. For if it were not so, regarding every prohibition of a "peel" (klipah) when it is cooked, we would require sixty times against the entire piece attached to the place of the peel; rather, since the prohibition is not in its own right, we are not concerned with it. The great Acharonim have already refuted whoever wishes to say so [see Shach subsection 9, and Taz subsection 6].

And if there is sixty against the place of the incision, or against the whole of it, or against the place of the knife according to the laws that have been explained, some say that even the radish or the onions are permitted, and there is no need to select them out from the cooked dish when they were cut with a meat knife and cooked in milk, since there was no prohibition upon them. However, when they were cut with a prohibited knife, one must select them out [Taz, subsection 5]. And there is one who asked that even with a meat knife, who is to say that all the meat flavor in the radish was squeezed out into the pot and nullified? Perhaps some meat flavor remained in the radish and it became prohibited by the milk [Pri Megadim in Shiftei Da'at, subsection 8]. And one could bring a proof for this from one who inserts a dairy spoon into a meat pot, for even if there is sixty, the spoon is prohibited, because we do not say that all the milk in the spoon was squeezed out into the pot, and here too it is so. However, this is not a question, for certainly with a mere insertion one must fear that perhaps it was not all squeezed out, but with complete cooking, it is certainly all squeezed out [and so wrote the Havat Da'at, subsection 1]. Furthermore, from a spoon there is no proof for a small food item that is inside the pot like the radish and the onions that are inside the pot, for even if they are not cut into thin pieces, nevertheless they are few in quantity against the cooked dish, and it is obvious that everything within them is squeezed out into the cooked dish, and there is no doubt in this at all.

Our teacher, the Rema, wrote in section 1: And some say that if one cut a radish with a forbidden knife, the whole of it is forbidden; and similarly, if one cut it with a meat knife, the whole of it is forbidden with milk. And such is the custom ab initio, but ex post facto one should only forbid the thickness of a finger-breadth. Thus far his words. And we have already explained that this is the opinion of the Rashba, that a sharp food forbids the entire piece, but most of the poskim do not hold so. Therefore, ex post facto, such as if they placed it into a cooked dish or the like, one does not need to require sixty except against the place of the finger-breadth according to the laws that have been explained, but ab initio, such as to eat them with milk, one must forbid the whole of it. And one should not ask that if so, when one cut it with a forbidden knife, we should also not forbid the whole of it since this is ex post facto, for this is no question at all; for we only permit ex post facto regarding the matter that it should not forbid another thing by way of its total forbidden status, such as if they placed it into a cooked dish and there is not sixty in the dish against the whole of it, but not regarding the matter of the forbidden status itself [and so it appears in the Shach, subsection 10, see there].

And know that a sharp item is effective only when there is the pressure of a knife, such as a radish that one cut with a knife, or that one crushed in a mortar which is also pressure, or that one placed in a trough and cut it very finely with a wooden knife called a "hack-messer," or that one grated it with a grater called a "reib-eisen" as is done with "chrein" and it is "tamcha" in the language of the Gemara. And similarly, in cooking, a sharp item prohibits, for cooking also causes much to be exuded, and consequently a sharp item exudes more. And specifically when the primary part of the cooking is a sharp item; but if there is a little sharpness in the cooking, such as when one puts peppers into a cooked dish or into fish, the dish is not considered a sharp item, and we have already explained this in siman 95, section 15, see there. But a sharp item through mere placement, such as if one cut a radish with a permitted knife and placed the radish into a cold prohibited vessel, it is nothing. And similarly, when one placed it in a meat vessel, it is permitted to eat it with milk, for as long as there is no pressure or cooking here, sharp items and non-sharp items are equal [and so wrote the Taz, subsection 3, and see Pri Megadim there]. And similarly, the pressure of a knife without a sharp item is nothing, and the law of a knife is like the law of other vessels, that if it is not ben yomo and it is clean, it is permitted even when it is boiling from a kli rishon, and all the more so that the pressure of a knife with a cold item is nothing if it is not a sharp item. And the details of the laws of a knife will be explained in siman 121 with the help of Heaven [and see Shach, subsection 6].

And there are those who asked how it is possible to say that regarding every sharp thing, that which is not of its day is like that which is of its day like a pinch of asafoetida, for if so, how did our Sages, of blessed memory, say (Avodah Zarah 75b) regarding the vessels of Midian that the Torah only prohibited a pot of its day, for should we not be concerned even with one not of its day that perhaps they cooked sharp things in it? And there are those who wanted to say that in truth the entire primary law of a sharp thing is not from the Torah but rather from the Rabbis, but it does not appear so from all the Rishonim, and also it is not logical at all, since imparting flavor is certainly prohibited by the Torah according to the one who holds that every imparting of flavor is from the Torah, as will be explained in siman 98 (Shulchan Aruch Yoreh Deah 98), which is the opinion of most of the poskim. However, regarding the vessels of Midian there is no concern at all for a sharp thing, as it is not common to cook the entire food from sharp things, and they only put sharp things into the food, and because of this it is not called sharp, as I wrote in the previous section. And besides this, the Rashba, of blessed memory, wrote in a Responsum [siman 497] that there are several doubts: perhaps they did not cook in it today at all; and if you should say they did cook, perhaps they did not cook prohibited things; and if you should say they cooked prohibited things in it, perhaps they cooked things that impair the cooked food, see there; and furthermore, perhaps they did not cook sharp things in it. And for this reason also, we permit the ordinary vessels of idolaters because they are presumably not of their day, and we are not concerned for sharp things [and see Kereti U-Peleti subsection 2].

The consensus of most of the poskim is that which the Sages, of blessed memory, said—that due to the sharpness of the radish it absorbs much, as has been explained—is not specifically a radish, for the same law applies to garlic, onions, and horseradish which is called "krin," as we see through our senses that all of these possess more sharpness than the radish. Similarly, anything similar to these is a "sharp thing." Regarding sour fruits, it is implied from the words of our teacher, the Beit Yosef, in section 2 that they are a "sharp thing," and it must be said that they are extremely sour, for ordinary sour fruits such as apples, pears, and plums which are called "poymen" and cherries do not belong to be called a "sharp thing" unless he placed them in vinegar [see Taz, subsection 9, and what he wrote in subsection 8 requires further study, for that is regarding the matter of "not of its day," and examine it closely]. Similarly, sour vegetables such as cucumbers, and cabbage, and sour beets, as well as other types of vegetables, it appears through our senses that they have no sharpness at all. Regarding "borscht" that they make in Russia from bran with water, it is a "sharp thing" [Taz, ibid.], and this is when it is very fermented such that it is impossible to drink it raw without mixing in water, but ordinary common "borscht" is not a "sharp thing" [Beit Hillel, and Pri Megadim, ibid.]. And the herb called "shchav" and "batvinya" is also not a "sharp thing." And know that "radish" we are accustomed to interpret as what is called "retach" in our language, [and in my youth I heard from one of the great ones that a certain Gaon was lenient regarding "retich" whose skin is white, and said that the one whose skin is black is sharper, and the senses testify thus, and he said that the "retich" that grow in the Land of Israel and in Babylonia all have black skin and are very bitter, and it is possible to rely on this in a case of loss]:

Our teacher, the Beit Yosef, wrote that salted fish is equivalent to cutting a radish with it. Thus far his words. According to this, regarding our herring, if one cut it with a forbidden knife, the thickness of a peel is certainly forbidden, and according to the opinion of our teacher, the Rema, it should be forbidden in its entirety ab initio. However, he himself wrote in his book Torat Chattat in the name of the Issur V'Heter HaAruch that if one cut salted fish with a forbidden knife, it requires only scraping, and if one cut it before they were salted, rinsing is sufficient. Thus far his words. And it requires further study why he did not comment here in the Shulchan Aruch. And one must say that here it deals with very salty fish, for then, due to the sharpness of the salt and the pressure of the knife, it absorbs more [Shach, subsection 16]. In any event, one should not forbid herring and other salted fish more than the thickness of a peel even where there is no great loss, and likewise from milk to meat or vice versa. But the soaking water of herring, which is called "lyak," is very strong and its law is like a sharp thing when cooked, and all the more so vinegar is a sharp thing, and lemons are sharp, and likewise pickled olives are a sharp thing for they are as sharp as onions [Issur V'Heter HaAruch, 38:9], and all the more so lemon juice and the water of pickled olives are very sharp. And any sharp thing, if it is completely dry without moisture like a radish or onions, they are permitted even when one cut them with a forbidden knife [so it is explained there], and there are those who hesitate about this, as will be explained with the help of Heaven.

Our teacher, the Beit Yosef, wrote in section 3: Spices that were crushed in a meat madocha that was ben yomo are forbidden to be eaten with milk. Thus far his words. But in one that is not ben yomo there is no prohibition, and this follows the first opinion in section 1. And even though in siman 103 he ruled anonymously like the second opinion, that is regarding a prohibited substance where nat bar nat is not applicable, but regarding permitted substances he holds that we do not apply two stringencies, nat bar nat and not ben yomo [Kreti U-Pleti subsection 5, and the difficulty of the Taz subsection 10 and the Shach subsection 19 is resolved, and so wrote the Pri Megadim]. Nevertheless, regarding the law, our teacher, the Rema, wrote here as well that there are those who say even if it is not ben yomo, and such is the primary ruling as I wrote in section 4. And from these words of theirs it implies that even with a dry substance a sharp substance prohibits, for spices are dry, and this is not like what I wrote in the previous section. And there are those who instruct so for the halacha, that regarding a sharp substance, moist is equal to dry [Pri Megadim subsection 17 in the name of Minchat Yaakov]. However, it can be said that from here there is no proof: first, because crushing is worse than the pressure of a knife, for since one crushes many times it draws out the absorbed flavor, and also there must necessarily be a bit of moisture as the senses testify to this, which is not the case with a knife. Furthermore, in a madocha there are two sharpnesses: the sharpness of the spices and the sharpness of the madocha itself, for since one crushes in it constantly it possesses much sharpness, and this is not applicable to a knife.

And behold, in section 2, our teacher, the Rema, wrote that nevertheless it is permitted to eat sharp preserves of gentiles, such as ginger and the like, for they have vessels designated for this, or they pluck it. Thus far his words. But without this, it would be forbidden even if the vessel was not a ben yomo. And from this too it cannot be proven that he holds that a sharp item forbids even in a dry state, for it is possible his intention is regarding moist ginger which has moisture, or even if it refers to dry ginger, it can be said that it is their way to crush them in a mortar, and we have already explained that a mortar is different. However, there are poskim who hold that ginger is not a sharp item at all [see Shach, subsection 17], and one may rely on them in a time of pressing need, and in our language we call ginger "ingber." And so too it is permitted to buy spices that were crushed in their vessels because the vessels are designated for this and they do not use them for any other use, and therefore even if they are very sharp it is permitted [Be'er Heitev, subsection 13, in the name of Nachalat Shiva], and so too it is permitted to eat the fruits that they fry in honey or in sugar, for regarding this there are designated vessels, and such is the custom to eat the "konfekturen" brought from afar, and so too all types of "konditerski" fruits that are fried are permitted for this reason.

All this that they said applies to the radish itself, and the garlic and onions themselves, and likewise all of them; but if one cut the greens that are upon them, there is no concern, for in their greens there is no sharpness at all. And likewise, if there is a doubt whether the radish was cut with a forbidden knife, we follow the lenient view, and likewise with all of them. Therefore, one may buy radishes that have cuts on the side of their tails, for we hang the matter on the assumption that it was done with a spade or a hoe. Furthermore, there are many doubts in this matter, for perhaps the knife was not "of its day," and perhaps we hold according to the opinion that maintains that except for asafoetida, the prohibition regarding a sharp thing only applies to a knife that is "of its day." And if it is known that the knife was "of its day," some say it is forbidden, for perhaps they were cut with the knife and it would be a doubt regarding a Torah law [Shach, subsection 12]. And some permit even in such a case because the radish has a presumption of permissibility [Pleiti, subsection 8], and this is not a complete presumption, as is understood, but rather one can say that it is a double doubt: perhaps they were not cut with this knife, and if you should say they were cut, perhaps he previously cut a turnip with it which nullifies the taste of the radish, as will be explained. Therefore, one should be lenient in all cases as long as it is not known to us that it was cut with a forbidden knife that was "of its day." And in a place where none are found to buy except those cut with a knife that is "of its day," one may permit buying them and cutting from them the thickness of a "peeling," for in such a case one may rely on this opinion that it does not forbid the whole of it, as this is the opinion of most of the poskim, as I wrote in section 5.

Lemon juice that the idolaters bring, for they cut the lemons and extract the acidity from them, and they call it "lemon juice" [Turei Zahav subsection 11], and likewise pieces of salted fish that they bring in barrels for one who holds that this is considered sharp, nevertheless they are permitted. This is because they bring many together, and even if some of them were forbidden—those that were cut first with a forbidden knife—they were nullified by the others cut afterward which are not forbidden. And even though we hold that "a piece becomes carrion" regarding other prohibitions, and if so, everything he cut becomes carrion, nevertheless here this does not apply, because the essence of the forbidden taste was already completely nullified in the first pieces, and therefore they are all permitted, and likewise anything similar to this. And it is not similar to what was explained in section 8 regarding a radish that was cut very thin where one requires sixty against all of it, for here it is different since this is the way of commerce where they make many barrels and cut them by the thousands, certainly the taste was nullified in these first ones. Furthermore, it is a doubt if the knife was "of its day," and perhaps we rule that with a knife that is not "of its day" one does not forbid a sharp food except for asafoetida, and furthermore since this is the way of commerce one can say that they have specific knives for this. [See Bach and Shach subsection 20 who struggled with this, and according to what I wrote the words of the Rema are clear in their reasoning, and see Kereti U-Peleti subsection 6 who also concluded thus, and therefore in all such cases there is no concern here, and examine this closely]:

Our teacher, the Rema, wrote in section 4 that from this law of lemon juice which has been explained, therefore in some places they eat the cabbage called "komposht" even though it is sliced and cut, and there are places that are stringent in this, and one should not change the custom; but other things that are not sharp, such as apples or dried fruits [so it should be said] and the like, the practice is to permit them like lemon juice and one should not be stringent at all. Thus far his words. The explanation of his words is that this cabbage is cut after it has become sour, for this is not our cabbage which is called "kroit," and in the Russian language "kapusta," for that species is cut before the souring; and furthermore, that species is heavily presumed to have worms and it is forbidden to eat that of gentiles because of the many worms found in them. Therefore, even though they practiced eating their "ogurkes" and "burikes" in which there is no concern of prohibition because the vessels in which they set them are clean, and even though they set the "ogurkes" in hot water, ordinary vessels are not "ben yomo," and furthermore they boil the water in clean vessels so that they do not absorb a tainted taste; nevertheless, "kroit" is not eaten in any place because of the worms. However, this species of cabbage is a species that is not presumed to have worms, and they cut them after they have become sour, and their law is like the law of lemon juice. However, there are places that are stringent regarding cabbage, and some say that these places are stringent also regarding lemon juice, for it is one reason [Taz, subsection 12], and some say it is not so, for regarding lemon juice even in those places the practice is to permit because they have specific vessels for this [Shach, subsection 20]. And this is explicitly implied from his wording, for he concluded that regarding other fruits the practice is to permit like lemon juice, and it is explicitly implied that regarding lemon juice the practice is to permit in every place.

A sharp thing, when placed in water, its sharpness is neutralized, as in the end of siman 69 regarding brine that is neutralized in water, see there; and so wrote the Tur in Orach Chaim siman 447 regarding olives, see there; and similarly, when one sweetens the sharp thing with honey or with sugar, its sharpness is neutralized. For this reason, the sages of Prague ruled regarding a dish of many onions with meat that was stored on Shabbat in a milk pot that was not ben yomo, that it is permitted, because they cook the onions on Friday beforehand in water, and afterwards they place them in the meat pot, and their sharpness is neutralized [the Gaon Rabbi Zalman Margolios in Yad Ephraim], and from this one may judge all similar cases. And so it appears to me that regarding fish, when they are cooked with many peppers and many onions, nevertheless, the abundance of water and the fish themselves weaken the power of the sharpness; and similarly herring, even according to the one who holds that they are like a sharp thing, and they cook them in vinegar and honey, the honey sweetens the sharpness of the vinegar and the herring and their law is not as a sharp thing; and similarly radish and onions, when one places oil or fat in them, their sharpness is neutralized. [And proof for this is from Shulchan Aruch Orach Chaim siman 321, see there in the Taz and Magen Avraham, and examine carefully]:

If one cut cucumbers with a milk knife, it is permitted to eat them with meat by means of mere scraping, which is less than a peeling, for a peeling requires at least a thin membrane that can be removed at once, but scraping is less than this; for in truth rinsing alone should suffice, and it is only because of their moisture that rinsing is not effective for them and they require scraping. And so too conversely, when one cut them with a meat knife, it is permitted to eat them with milk by means of scraping. And included in cucumbers are all our types of vegetables when they are not pickled, such as cucumbers, beets, cabbage, pumpkins, and the like. And if one cut turnip with it, such as Rüben, Möhren, Brusca, it does not even require scraping, and mere rinsing suffices, because they do not have much moisture. Furthermore, even when one cut a radish after the turnip, the radish is permitted by means of rinsing like the turnip, for thus our sages of blessed memory received that the turnip nullifies the taste of the fattiness from the knife [Rashi 112a (Chullin 112a)], because the taste of the turnip is distinct and nullifies the taste emitted from the knife. And specifically a turnip whose taste is distinct, but a vegetable or bread and other things do not nullify the taste. And even with a turnip, one should not permit cutting the radish except for one time, but not many times, unless one cut a turnip every time between each cutting of a radish. And this is the law as well regarding a knife of forbidden food. Nevertheless, to do so ab initio—to cut a turnip with it in order to cut a radish with it afterwards and permit it thereby—is forbidden [Shach subsection 23]. And if one cut fish with a knife of idolaters, even though it has moisture, nevertheless, since scraping and peeling are impossible with fish, therefore a certain great authority ruled to rinse it and scrub it very well [Chavat Yair], and even with a knife used within the day one should permit it in this case [ibid., see Pitchei Teshuva]. And know that there is one who says that with a knife of forbidden food, the cutting of a turnip does not avail to cut a radish with it afterwards [Pri Megadim subsection 22], but I do not know from where we have this to distinguish, for since the reason is because it nullifies the fattiness, if so, what difference is there to me between meat fattiness or forbidden fattiness? And certainly the law is so, that ab initio it is forbidden to cut with a knife of forbidden food, but it does not concern this law at all. [The Bach wrote: a worm that was cut with a knife, there is no concern in the matter]: