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Kosher Sushi, Not Your Bubby’s Gefilte Fish!

Rabbi Sholem Fishbane

Kashrus Administrator of the cRc 

Jackie Mason once joked that sushi was created by a Jew who wanted to open a restaurant without having to cook anything in the kitchen. What the comedian didn’t know then is what has become an intriguing, multi-faceted issue now. Even though Jews were eating raw fish long before the advent of the sushi bar (herring, anyone?), sushi presents an intriguing, complex challenge for kashrut experts.

Translated from the Japanese, “sushi” means “vinagered rice.” In the 7th century, the Japanese acquired the new technique of pickling, which consisted of packing fish with rice. As the fish fermented, the rice produced lactic acid, which in turn caused the pickling of the pressed fish. Nare-Sushi is 1300 years old and refers to the finished edible product resulting from this early method.

However, due to its lengthy process, anywhere from two months to a year, a quicker form was needed. The 17th century saw the introduction of rice vinegar into the sushi rice. The vinegar served to reduce the lengthy preparation while adding a pleasant flavor of tartness. Although the process of fermentation was now shortened, it wasn’t until the 1820’s that Sashimi (fresh sliced raw fish) was introduced, and customers were able to buy freshly prepared sushi straight from the sushi stall.

There are various halachik questions in relation to Sushi and why you may not buy even raw Sushi from a non-certified establishment. We can best explore it by analyzing each ingredient and its related issues:

Ingredients: Wasabi; Soy sauce; Pickled ginger; Sesame Seeds; Rice vinegar; Seaweed (Nori); Rice; Fish

Other common ingredients are avocado; carrots; cucumbers; green onions; mayonnaise; chili sauce. While the raw vegetables do not need a hechsher, the others most certainly do.

Wasabi is a member of the horseradish or mustard family, but don’t be fooled. Real wasabi is one of the rarest and most difficult vegetables in the world to grow. In the last twenty years, because of low supply of fresh wasabi rhizomes, the green smooth textured clump on the side of your sushi dish, is rarely real wasabi. More commonly, it is ordinary horseradish, mustard and food coloring and therefore requires a reliable kosher certification.

In Japan, where a sushi chef is regarded a true artist, and becoming a sushi chef is a highly regarded and respected profession, wasabi is prepared by grating the fresh rhizome against a rough surface. Some Japanese Sushi Chefs will use only a sharkskin grater. The sharkskin gives grated wasabi a smooth, soft and aromatic finish. Needless to say, this procedure certainly could complicate kashrus matters.

Soy Sauce is an extremely important ingredient in Asian cooking and is a dark, salty sauce, made by fermenting boiled soybeans and roasted wheat or barley. Companies that produce soy sauce can and do make other non-kosher products, a reliable hechsher is necessary.

Pickled ginger can be brined in either vinegar that always requires a hechsher or plain salt water. Since these are sharp substances (davar charif), they would contract the utensil’s kosher or treif status more quickly and effectively than a bland ingredient. Sugar and coloring are added to finish the making of the pickled ginger. Due to the ingredients and process, only ginger with proper supervision should be used.

Sesame Seeds are generally kosher and are fine to use.

Rice Vinegar can be a problematic ingredient due to the utensils used in its production. Many vinegar companies cook non-kosher wine vinegar in the same plant and could possibly spread its non-kosher status to the other innocent vinegars.

Nori is basically seaweed paper. An original Japanese food product, it is made from various species of red alga by a shredding- and rack-drying process that resembles papermaking. Nori is the sweetest sea vegetable and when toasted, nori turns a bright green and becomes even sweeter. It is high in fiber, protein, vitamins and minerals and, seaweed provides up to ten times more calcium and iron by weight than dairy products.

There are two basic kosher issues with nori sheets. One is the possible contamination of flavors and the other is the possible existence of insects.

There is no question that some companies add flavoring, including shrimp flavoring, to their nori. Although the nori packaging should declare if it has flavoring in it, the reliability of the labeling departments in these Far East companies is questionable. There is also the possibility that the non-flavored sheets can be toasted on the same production lines as the non-kosher flavored nori.

It was not easy trying to get to the bottom of this but, after contacting several experts on the matter, it seems that there are three types of nori sheets. First, there is Yaki Nori, the type used for sushi. This is a roasted nori that has no added flavors and, since it is roasted, there should also be less concern for bugs. Second, there is Ajitsuke Nori, which is used in soups and other foods. It is flavored with Soy sauce, Mirin (sweet sake), sugar, and hidden flavorings of shrimp. This is never used for sushi and can never be kosher.

There are also fresh nori sheets, which are frequently infested with bugs, so kosher consumers should avoid these. Some sushi shops use frozen fresh nori.

The experts I contacted also feel that most production lines that produce nori are either dedicated to regular non-flavored nori or dry the regular nori sheets in dedicated ovens while the flavored varieties are dried in separate ovens. Nevertheless, it is important to know that even if the plain nori was toasted on a line that had toasted flavored nori, there are various halachik reasons not to be overly concerned about it.

The main concern with nori is non-kosher fish or crustaceans. Nori is a vegetable product and, like all vegetables, it must be checked for infestation. The most common insect invaders are sea horses and mini shrimp. Depending on the time of year and particular harvesting method, the infestation levels can vary. Checking nori is more difficult than other vegetables products since you are not looking merely at the exterior or a whole vegetable, but multiple layers of the thin toasted sheets wherein the non-kosher fish or crustaceans can hide.

Most companies rely on electronic eyes (lasers) to look for bug infestations and the quality of inspection depends on the country. Many hashgachos rely on this laser system but, recently, a major hashgacha that works with nori issued an alert that they do not stand behind their hechsher on all nori sheets due to high levels of insect infestation. They now have a mashgiach in the plants checking the nori and are certifying only specific lots. Their goal is for the mashgiach to determine how much more effective they need to make the lasers so that they can, once again, be comfortable relying on the laser system.

Ultimately, it is highly recommended to buy nori with a reliable hechsher. If this is not possible, you may use it provided that you check for the bugs by a good, strong light. Remember to look between each layer!

Rice – Is the rice a problem, considering that the rice cooker and bamboo steamer are created specifically and designated only for the rice?

The simple answer is yes. It is a problem because cooked rice is one of the types of foods that requires bishul yisroel (an active Jewish participation in the cooking) in order for it to be kosher. Unless you know for sure that a Jew turned on the rice cooker, the rice would not only be non-kosher but it would make the rice cooker itself non-kosher.

A related common consumer question is the type of rice one can buy. It is common knowledge that raw rice is kosher and, as previously discussed, cooked rice is problematic due to the bishul yisroel issue. But what about rice sold as par-boiled?

It is safe to say that partially cooked rice doesn’t require bishul yisroel in the factory to make it kosher since we assume that the final cooking will be done by a Jew. One can generally tell whether a particular par-boiled rice was partially or totally cooked by looking at the cooking directions. If they say to cook it for 10-15 minutes then it is, most probably, partially cooked. But, if they say it only requires 5 minutes to cook, this indicates that the rice was fully cooked and the additional cooking time simply serves to reheat and rehydrate the rice.

Parboiled rice, which requires further cooking of at least ten minutes, does not constitute the problem of bishul akum (food cooked by a non-Jew). Even according to the Mechaber (113:9) that prohibits food cooked by a non-Jew more than 1/3, it is not a problem here since it is not edible at all without further cooking by the consumer).

Thus we can conclude it is important for kosher consumers to avoid uncertified, fully cooked rice.

Another possible issue could be in the actual handling of the rice when preparing sushi rolls. Being rather sticky, the rice can be difficult to work with and every sushi chef deals with it in their own unique way. Some might smear some avocado on their hands but I have seen others dip their hands into oil (which always requires proper certification) to make rolling more effective.

Fish – Unlike other meats, fish that have fins and scales do not require further processing, such as draining the blood, to be considered kosher. However, some sushi bars soak their raw fish in brine to keep the color and consistency and nevertheless sell it as fresh. The consumer would never really know and they certainly would not share this information with us. As pointed out before, brining can be a kosher headache.

A very interesting question has arisen with the advent of sushi, this raw fish dish, sweeping the nation. As seen in this article, the concept of needing bishul yisroel (a Jewish presence in the cooking) plays a major role in kosher certification. The two basic requirements for a food to be under this category is, that it must be a food that one would serve at a royal banquet (as opposed to something like a bag of gummy worms) and that it is generally eaten cooked, not raw. If the food is normally eaten raw but you decided to cook it anyway (like a baked apple) it is still kosher even without a Jewish involvement.

Fish has always required bishul yisroel since it definitely a royal dish and only eaten after some type of cooking. Now the question is, has sushi become so commonplace as to change the bishul yisroel status of all fish?

This question is closely related to the Halachik question of food prepared in a country where it is exempt from bishul akum to be eaten in a country where it isn’t and vice versa. For example, in Brazil, where hearts of palm are grown (and canned), they are eaten raw. Hearts of palm only grow in tropical climates and therefore only canned/cooked hearts of palm are consumed in the continental United States. Nonetheless, it would seem that there is no issue of bishul akum since at the time of the cooking the hearts of palm were in a country where they are eaten raw. Furthermore, there is no reason to think that Americans wouldn’t eat raw hearts of palm if they had such an option (in fact, fresh hearts of palm are served as an “exotic vegetable” to American tourists in Hawaii). In this case, the Poskim have ruled that since Brazilians eat raw hearts of palm, there is no reason to think that Americans wouldn’t do the same if they had such an option.

Generally speaking, if a non-Jew cooks a food in a country wherein that food is eaten raw, then that food remains permitted to the kosher consumer regardless of where it is eaten. This is because food that is eaten raw is precluded from being bishul akum and, subsequently, the non-Jew’s cooking is not considered to be a meaningful act. Thus the food was effectively not cooked by a non-Jew and is not, and can never become, bishul akum.

Does this translate to sushi? Although raw fish is certainly eaten raw in the Orient, and increasingly so in America, the Poskim have ruled that the popularity of sushi has yet to change fish’s requirement for bishul yisroel for the following reasons:

1. Foods aren’t considered “edible raw” until most of the people in a city consider it edible raw. Thus, although many restaurants have sushi bars and many people enjoy it, there are also many people who can’t imagine eating raw fish. Moreover, many people living in smaller towns and rural areas have not been exposed to sushi and would still find it repulsive to eat raw fish. Hashgachos on commercial facilities must keep in mind that they service all of the USA and not just New York, Los Angeles, and Chicago.

2. Sushi is generally eaten with rice and seaweed etc. such that the sushi merely adds “zing” or “tang” to the cooked food. As such, we might say that raw fish is still not edible raw and can only be used as a sort of “spice” for other foods.

3. Only the freshest fish is sushi-grade and the fish used for canning, smoking and other uses, isn’t sushi-able. As such, even if there weren’t a concern of bishul akum on the sushi-fish, there may be a concern on other fish.

For the reasons explained above, and the additional reason of Mar’as ‘Ayin (whereby eating kosher food in a non-kosher restaurant, one can cause an outsider to believe that it is fine to eat anything in the restaurant), one may not eat sushi in a non-kosher restaurant.