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At a non-kosher restaurant, is thinly-sliced raw fish kosher?

Let's assume one sees the preparer clean the knife and cut from the whole fish.

Also, let's assume this raw fish is sashimi — minus the usual rice, and minus the usual Asian white radish.

(I'm not asking whether or not it's permissible to eat it: if I were, we'd have to consider maris ayin. I'm only asking whether or not it's kosher.)

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There is no such thing as "setting aside maris ayin". Maris Ayin is halacha, and must be considered within every action. It's like saying "setting aside theft, do I have to toivel plates that I stole from a Jew?" – user1095 Feb 26 '12 at 11:53
@Will I don't know. Do I? I would guess not. But what if I stole them from a Non Jew? Now that is a good question. – Double AA Feb 26 '12 at 14:15
@Will I don't think your comment is true. Marit Ayin is a halachic concept, but not a halacha itself. There is actually a really fun contradiction with " dan likaf zchut" I think I'll ask a question about it. – avi Feb 26 '12 at 14:18
@Will I just read for example, that Rav Moshe Feinstein wrote that if a person is very hungry they may eat kosher food in a non-kosher restaurant, because pain and suffering override rabbinic rulings. – avi Feb 26 '12 at 14:59
@Will then we should ask the question of whether or not eating kosher food at a non-kosher restaurant is even a problem. As Curiouser points out here, R' Kamenetsky holds that it is well known nowadays that kosher food can be found even in non-kosher restaurants. – yoel Feb 26 '12 at 16:27
up vote 7 down vote accepted

If the fish is kosher (i.e. you can identify it as a kosher species in an acceptable way, e.g. you see the scales on the whole fish, or for skinless salmon by the red color of its flesh which is a sign of kashrus), and everything is cold and clean (fish and utensils), then the fish can be eaten l'chatchila. This is based on the Shach in Yoreh Deah 91 (#3), as well as the discussion in the Aruch HaShulchan in Yoreh Deah 91:6, where it is clear that one may use cold, non-kosher utensils to eat kosher food, as long as it is done only occasionally.

Since nothing is hot, the question of ben yomo or eino ben yomo (whether it was used in the last 24 hours) does not even matter. And as long as you are just eating the fish, then the issue of charif does not matter either. (If however, a non-kosher knife was used to cut a charif food, like an onion, then you could not eat the onion. But if it subsequently cut fish, then the fish is still fine, because fish is not considered a davar charif).

So the bottom line is that the only issue is whether the fish is kosher and cold and the knife is clean. If all you are eating is the raw fish, then there are no issues of charif or kli ben yomo.

(For more on the topic of identifying skinless salmon or other salmanoid fish based on its distinctive red color, see: http://www.oukosher.org/index.php/common/article/the_kashrus_of_skinless_salmon1/ . For white-fleshed fish, the topic becomes more complicated, whether one is expert enough to identify a fish based on its flesh and whether that expertise is valid)

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I'm only going to comment about the sushi here, but Salmon skin, Tempura, cooked eel, and Seared are all common ways of serving and preparing sushi dishes in which the food is hot and cooked. – avi Feb 26 '12 at 16:21
This answer will lead to many people eating non-kosher food, and should not be followed. – avi Feb 26 '12 at 16:40
This answer needs to be adjusted to include more specific guidelines on how fish other than salmon can be identified in an "acceptable way" otherwise it is very misleading. – Yirmeyahu Feb 26 '12 at 16:47
@Will actually, you can rely on a sushi chef to tell you the correct fish that they are serving. Ofcourse, most fish names get lost in translation. – avi Feb 26 '12 at 18:48
@msh210 sushi grade fish is very high quality, very freshly caught, and usually (I imagine tuna may be an exception) cut from that fresh fish on the day it will be used. It may be that the same holds true but when one deals with fish used for sushi it is of a different level of quality than supermarket fish. – yoel Feb 26 '12 at 21:42

Normally it is not.

When using a knife to cut kosher food there are two requirements.

  1. That the knife is completely clean.
  2. That the knife has not been used since it was cleaned/kashered for 24 hours.

Normally, a person might want to argue that the Fish is cold and so none of these are really issues. However, Sushi is normally NOT halachically cold.

There are two types of "heat" when dealing with kashrut.

  1. Physical heat, such that your hand would not want to touch it.
  2. Spicy "heat", which has a strong flavor.

Under spicy "heat", the common example is an Onion. If the knife cuts an onion, and before cleaning off the knife cuts squid or cooked eel, or a number of other unkosher foods found at a place that serves Sashimi, or more likely, even cuts them at the same time, the knife is no longer kosher. In a restaurant that serves sashimi there is a good chance that Wasabi, Soy Sauce, Radish, Rice wine Vinegar, Ginger, or many other vegetables, all of which count as "hot" will have treifed up the knife less than 24 hours before your sashimi was cut.

I have heard of people who have their own knife which they have given to a sushi chef in places where kosher agencies are not around.

Edit: I see the need to quote a source here so:

Furthermore, davar charif is not limited to imparting tastes into food; it can also impart a taste into a utensil. One scenario would be when a mixture of meat and sharp spices is being chopped with a blade. The sharpness of the spices combined with the pressure of the blade will cause the meat taste to become absorbed into the chopper.[16]

This stringency is also relevant to cutting boards. The Chochmas Odom[17] discusses cutting a piece of salty herring (a davar charif) on a non-kosher plate. He states that the combination of the sharp taste and the pressure from the blade will draw absorbed issur out from the plate and impart it into the fish. Similarly, Rav Shlomo Kluger[18] writes that if an onion was cut with a fleishig knife on top of a milchig plate, both the onion and the knife will absorb a combination of meat and milk tastes, thus rendering them both non-kosher.[19]

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Wasabi comes as a powder, mixed with water to form a paste. Ginger comes sliced and soaked in packages. I've never seen a sushi chef use his fish knife to cut either. There could be other kashrus problems here, but I don't think that a spicy knife is a serious concern in this case. – user1095 Feb 26 '12 at 11:57
@Will You've never heard of a Wasabi Roll? Also, if an ingredient is nearby, you have to be concerned that the knife will cut it. – avi Feb 26 '12 at 14:01
I'm not sure your explanation of a davar charif is correct. Even if we assume the knife is non-kosher (i.e. it was used to cut hot, cooked, non-kosher food), still that non-kosher flavor will not transfer to the raw fish if the knife had not been used in 24 hours, which is the usual chazakah. Davar charif means that if you cut a davar charif with an already non-kosher knife, then the cut food absorbs non-kosher flavor (because it is charif). But davar charif doesn't apply at all in the example you gave with the onion and squid -- I don't see how that is relevant. – Curiouser Feb 26 '12 at 15:32
@ avi: I don't believe you are correct. You keep mixing up the order. The common example is a fleishig knife used to cut an onion. Now the onion is fleishig. The knife is the same. – Curiouser Feb 26 '12 at 16:14
@ avi: I recommend you look in the Shulchan Aruch Yoreh Deah 96:1 and review the concept of davar charif, since your answer and comments seem to have it all backwards. – Curiouser Feb 26 '12 at 16:18

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