Kashrus Kurrents, Winter 2022

Our numerous sojourns through Galus not only defined and influenced the minhagim emerging from those foreign lands, but also infused our cuisine with bursts of ethnic diversity –  pierogi and cholopshkes from Poland, couscous and harira from Morocco, goulash and strudel from Austro-Hungary, and gravlax from Scandinavia. Our seudos feature dips from around the world – schug from Yemen, hummus from the Levant, guacamole from Mexico, and matbucha from Morocco. As our migration advanced to the shores of the goldene medina, kosher restaurants sprang up that offered consumers a bevy of ethnic choices, from Chinese won ton soup and Italian calzones to Persian kebabs and Lebanese shawarma.

The latest entry to that diverse menu is the proliferation of sushi – a traditional dish from Japan – that has been wildly embraced by Jewish communities everywhere and is now nearly as popular as apple pie (or potato kugel). It has found a place of prominence in virtually every kosher restaurant, wedding smorgasbord, and even the local pizza shop. Grocery stores, too, now carry sushi supplies, and with the establishment of a vibrant global marketplace, we can now purchase reliably kosher certified ingredients for the preparation of sushi from Tennessee to Taiwan, and all points in between.

A sushi roll, or maki, is a unique combination of rice, seasoned rice vinegar, and thinly sliced raw fish and vegetables, tightly rolled in black sheets of seaweed called nori. The four articles that follow touch on the kashrus implications of the main components of maki – tuna, rice vinegar, and nori – along with the proper brachos to make before partaking of this delicacy.

I.  Something Fishy About Tuna

Rabbi Dovid Jubiler, Cape Beth Din Kashrus Administrator, South Africa

While sushi and sashimi don’t get along too swimmingly with gefilte fish and schmaltz herring, we see these delicacies at many simchas. These Japanese foods are becoming increasingly popular in the Kosher market, but few people know just what takes place behind the scenes.

We might think that because fish used in sushi is raw and uncooked, what could go wrong? Well, on the “scale” of things allow me to enlighten you about sushi fish production.

Yellowfin Tuna (Thunnus albacares), a popular sushi delicacy, is mainly caught in Southeast Asia and is sold predominantly from Chinese fishing boats. They employ long-line fishing in contrast to a net method. When tuna is not designated for canning, this method is used in order to minimize bruising. Packed in chipped ice flakes, tuna is sold on auction to the highest bidder. Severe shortages of this overfished species and huge demand from the Japanese market drive the price up considerably.

These factors of supply and demand contribute to the perpetration of industry fraud  There have been recorded cases of other fish being substituted and sold as tuna. There have been instances where the accepted method of pas kaskeses, leaving a skin patch on the deboned and skinned fillet, has been adulterated.

These skilled perpetrators have cleverly developed a method of sticking scaled skin patches onto the cuts. The enzymes in the meat/skin and the subsequent freezing of the cuts cause the skin patch to appear to have been grown on the fish. In order to beat these scallywags at their own game, we check the tuna when it arrives at the factory – whole, unskinned, and fresh. We check that there is no other fish accessible in the plant at the time of kosher processing, and we confirm that what is packaged is certified kosher tuna.

As an imported product, the US FDA is extremely strict, testing that there are no nasty germs, histamines or parasites in this raw product. Did you know that after the tuna has been skinned and cut it is particularly prone to infection? Therefore, to help the product pass customs inspection with a clean bill of health, the manufacturer will soak the fish in an antibacterial preservative solution which contains chemicals and disinfectants. The mixture (a powder mixed with water) also may act as a firming agent and flavor enhancer. The tuna is immersed in these solutions for a prescribed amount of time to ensure that the meat of the fish is penetrated sufficiently to do its job. We make no assumptions! We carefully check that these solutions are reliably kosher certified, in spite of the fact that the certified product is more costly.

Another cost-saving method of germ prevention is ethanol. Ethanol can be made from a variety of source materials that will be converted into alcohol. In South Africa, the manufacturer will use the cheapest starter material available. The raw product used to make alcohol is seasonal, and the cheapest one is the one that is most plentiful at the time. South Africa enjoys a fruitful grape season; that which falls off the vine and not turned into wine is used to make ethyl alcohol. Alternatively, alcohol from South Africa can also be made from sugar.

Often, there is a foregone conclusion that raw fish is automatically Kosher for Passover (KFP). Similarly, it is assumed that sugar-based ethanol is KFP. This may not be the case. To process sugar cane into sugar, amylase enzymes are used to break down the sugar cane cells so that there is greater yield for the alcohol manufacturer. This enzyme may be kitniyos, or even chometz!

When certifying a KFP sugar production, we ensure that the enzymes used are all KFP and that the enzyme starter materials are strictly KFP.  In the case of Passover-certified tuna, we see that the sugar-derived alcohol has KFP enzymes in it when it is produced and that the ethanol is certified as KFP.  Once all Passover conditions are met, we can then also certify the tuna as KFP.

Another issue that we often confront when processing kosher fish is cross-contamination with treif fish. Furthermore, do you know that the nice smoked red color on your tuna sashimi (with a skin-patch) may be due to a red dye bath of carmine (a brilliant color stable red derived from crushed beetles)? We make sure that all colorants are reliably kosher certified.

When we supervise fish production in a common facility, we segregate production and kasher the factory and equipment to ensure that the plant is dedicated to kosher fish production. We confirm that nothing is produced on Shabbos. When Bishul Yisroel is necessary, we light the smokers and make sure that there is no cross-contamination with treif fish in the smokers.

Clearly, there are many operators who will happily cut corners by spinning you a line. Don’t fall hook, line and sinker for the scam. Be an educated consumer and buy only kosher certified products!

II:  Creating Rice Vinegar

Rabbi Amos Benjamin, STAR-K Kashrus Administrator, Director of Far East Operations

One of sushi’s basic components is rice vinegar. Rice vinegar serves two purposes – it imparts flavor and it serves as a preservative so that the sushi will not spoil. Unlike grain vinegar or apple cider vinegar that uses grain alcohol in the process, rice vinegar uses alcohol from a rice wine popularly known as sake. In order to convert the rice into alcohol, a mold known as koji is used in the fermentation process.

Are there any kashrus concerns in the manufacturing of the koji mold, a basic component in the production of rice vinegar? Let’s first take a look at what is involved in koji production in Japan.

The first stage of the koji process is to mix raw rice and cold water. The rice is then transferred to a pressure cooker, where it is par cooked. The rice at this stage is barely edible. It still has a low moisture content and is nowhere near being fully cooked, so there would be no issues of bishul akum. After cooking, the rice is ready to be converted into the koji mold.

The rice is seeded with koji extract, which comes from a previously grown koji mold. The culture uses only rice, Aspergillus oryzae (a fungus which is inoculated into the rice), and water. The koji extract propagates the par cooked rice to create more koji. The rice is seeded with the koji extract, transferred to wooden trays and left to culture for five to seven days at a temperature of 45ºC. Now the koji mold has spread and is ready for the next step.

The molded rice is dried for two days with warm air. The completed product is known astanakoji. In order to produce the other finished product, koji-kin, the molded rice is passed through a sifter to separate the mold spore from the rice. The spore powder is blended with potato starch and is packed and ready to be used to convert the rice into sake (rice alcohol), which provides the basis for rice vinegar.

In a rice vinegar fermentation process, the rice’s natural starch is converted into a sugar, similar to the malting process of barley; this occurs when the rice is mixed with water. The koji is then added to the malted rice syrup along with other enzymes. The rice fermentation process converts the sugars into rice alcohol.

The sake alcohol is then separated from the solid rice. The liquid sake is then ready for a second fermentation process, whereby bacteria converts the alcohol into acetic acid (concentrated vinegar) – in this case, rice vinegar. The concentrated vinegar is diluted with water to 4.3% acidity and is ready to be mixed with sushi rice.

The bottom line: there is no issue of bishul akum with the fermentation of rice and the production of rice vinegar molds.

III:  The Making of Nori

Rabbi Tzvi Rosen, STAR-K Kashrus Administrator / Editor, Kashrus Kurrents

What is nori? Let’s begin with a dictionary definition: NO•RI / nōrȇ/ – an edible seaweed eaten either fresh or dried in sheets.

Nori is a form of algae, a simple organism that grows in the water. Nori, in fact, starts its life on land, where the nori seeds are sprouted, before being taken by the nori grower out to sea to grow on nets. As the nori grows in the sea nets, it is possible for unwanted sea creatures (e.g., seahorses) to get caught in the nori or in the nets. Once grown to maturity, the nori is then harvested. This harvested nori is then brought into a manufacturing facility where it first undergoes a visual inspection to remove any hidden marine life or unwanted seaweed.

Next, the nori is washed and filtered to remove sand and other debris. After the nori is softened, it goes through a second filter. The seaweed is cut, shaped, and pressed down into shaping boxes. It is pressed to remove excess water and is formed into sheets, whereupon the nori is dried for two hours at 50ºC.

Upon completion of this first drying process, the nori is separated from its shaping boxes and transported to a computerized optisorter that inspect the sheets for abnormalities in color and texture. If an unwelcomed seahorse were to pass through the filtration systems and baking process, it would be spotted by the optisorter on the line and the nori sheet would be discarded. It should be pointed out that the optisorter is not infallible. Kosher nori requires a mashgiach’s trained eye to spot unwanted crustaceans. Once the nori passes inspection, the sheets are boxed for a second drying in an electric oven at 80ºC to toast them for a crisper finish.

IV. Brachos on Sushi Rolls

Rabbi Mordechai Frankel, Director, Insights from the Institute

The general rule for a dish with numerous ingredients is to recite a bracha on the primary ingredient (the ikar) and not on the secondary ones (the tafel). If the dish does not contain any of the five types of grain, the ingredient of which there is the largest quantity will generally be considered to be the primary ingredient. In the case of sushi, that ingredient would be the rice; but the more prestigious ingredient is clearly the fish, which is considerably more expensive than rice. As such, the fish would also be considered a primary ingredient.

In addition, the filling and rice are not cooked together, and they remain distinct. Thus, both the filling and rice are considered primary ingredients, and both necessitate a bracha. The vegetables or fruit (such as avocado or mango) in the sushi roll are tafel to the other ingredients and do not require a bracha. Similarly, the nori does not require a bracha.

For this reason, Rav Heinemann shlit”a paskens that one should first recite Mezonos on the rice, and then She’hakol on the fish. A suggested way to do this would be to unroll one of the rolls and make the separate brachos on the rice and fish.