The Fisheries Research Center of the Fisheries Research Agency (FRA) is engaged in a project to find new fish from the world’s oceans that suit the Japanese palate.
In 1971, the former Marine Fisheries Resource Development Center was established as a public organization to research new fishing grounds and fish and shellfish, and to study business feasibility, and was given the mission to find fish and shellfish that had not been distributed in Japan before.
The seafood distributed domestically by the Center was called “development fish”.
The term “development fish” does not refer to the creation of new types of seafood through breeding or other means, but rather to efforts to make new use of fish and shellfish that have not been distributed domestically. A similar term is “substitute fish,” which is used in place of fish and shellfish that have been conventionally consumed, but developed fish are not intended to be substitutes.
For example, “Gindara (Black cod)” is a fish that was investigated in collaboration with the United States.
This fish is not a codfish, but a member of the Gindara family. At first, it was distributed mainly as surimi because it was black and unattractive, but later it was also consumed as fillets and boiled fish.
The “Karasugarei (Greenland halibut)” is found in the Arctic Ocean, the Bering Sea, and the Sea of Okhotsk. It is often used as Engawa in conveyor-belt sushi.
There is another fish called “Gasutoro“. This fish, named after the leader of the Cuban Revolution, is used in fried white fish. The meat of the “Gasutoro” is white and unctuous, and it is caught along with tuna in longline fisheries.
Since its establishment, the FRA has developed a total of 46 species of fish and shellfish, including Sunfish, Kingklip, and Jumbo flying squid, to provide new food sources. The “development fish” has also enriched our diet.
Unfortunately, the development of “development fish” ended about 20 years ago.
We would like to examine this challenging title that appears regularly in the media.
This story has not recently come to a boil; in fact, it is already widely known. However, the reason it is a recurring topic is due to the fact that the assumptions between the writer and the reader do not match. The reason for this is that the writer tends to exaggerate a bit in order to get people to read the article. The readers, on the other hand, are overwhelmingly uninformed and are led to feel uneasy about what they hear. Here’s what we guess.
So, in order to explain this issue properly, we will squash any ambiguities.
There are three major risks.
The first is food poisoning due to bacterial growth. The second is food poisoning by parasites. The third is the medium- to long-term effects on the human body of mercury, dioxin, microplastics, and other substances that accumulate in tunas.
We can say that food poisoning caused by bacterial growth is a very rare and serious matter that can affect the survival of a business, if only in sushi restaurants. Here are some data to support this. According to data from the Tokyo Metropolitan Government, the percentage of food poisoning cases occurring at sushi restaurants is less than 0.8% of the total number of food poisoning cases. The data shows that food poisoning rarely occurs at sushi restaurants.
The reasons for this are largely related to soy sauce, salt, and vinegar. First, soy sauce has bacteriostatic properties, and by marinating tunas and other fish in soy sauce, the growth of bacteria is inhibited. Second, salt has a bactericidal effect, killing bacteria on the surface of the fish. Besides, it uses osmosis to expel the rotting components of fish meat, etc. And vinegar also has a sterilizing effect. Since the ㏗ is 2~4, the bacteria are almost killed when they come in contact with vinegar. Sushi chefs put vinegar on their hands or wipe their knives with a cloth dipped in vinegar to sterilize them. Shari is made with vinegar and salt, so it is also sterilized. In other words, more steps are taken to prevent the growth of bacteria than in any other dish.
Next, we will examine food poisoning caused by parasites; Anisakis accounts for 50% of all cases of food poisoning. It can be said that raw seafood always contains parasites, but removing these parasites is the foundation of a sushi restaurant, and Anisakis, which can be visually identified, cannot be overlooked. On July 2, 2021, a method to kill Anisakis with a high current was also announced and will soon be put to practical use.
Also, it totally depends on where you eat. Do you buy it at the supermarket or fish market and eat it at home or a sushi restaurant? Even at the same sushi restaurant, there is a difference. Is it a conveyor-belt sushi restaurant with a chain or an individual restaurant run by a master and his apprentice? In our opinion, however, food poisoning caused by Anisakis has not occurred in private restaurants.
We will examine the medium- and long-term effects of toxic chemicals. First, let’s look at the effects of mercury. For example, the level of effect is naturally different for those who consume tuna every day and those who eat tuna once a week. Although the Japanese eat a lot more tuna than other countries, the effects of mercury accumulated in tuna have not yet been widely discussed. The effects of mercury on the mother’s body are well known, and the following warning is given by the doctor in charge.
In Japan, if you eat more than 160 grams of tuna per week, you need to be careful. Pregnant women do not bother to eat 160 grams of tuna in the first place. In addition, although Kuromaguro (Bluefin tuna), Mebachi (Bigeye tuna), and Minamimaguro (Southern Bluefin tuna) have safe amounts, Kihada (Yellowfin tuna), Binnaga (Albacore), and Mejimaguro (Young bluefin tuna) do not require any restrictions on the amount eaten. Also, there is no need to worry about canned tuna. This is also a well-known story.
And, this may come as a shock to tuna lovers, but it is the toro part of the belly that tends to accumulate the most dioxin, which is considered the best part of the fish. The toro is mostly fat, and dioxin taken in from feed and seawater accumulates there. In nature, the toro portion of tuna is normally about 20% of the tuna meat. However, in fattened tunas, 70~80% of the body is toro. The meat of fattened tuna is a habitat for dioxin. According to some research data, the amount of dioxin accumulated in fattened Kuromaguro was about 2 to 3 times higher than that in wild tuna, and in fattened Minamimaguro, it was about 2 to 10 times higher.
The final section examines microplastics’ medium- and long-term effects on the human body.
In the North Pacific Ocean gyre, famous for the Pacific Garbage Belt, plastic fragments have been found in the digestive tracts of 10%-35% of the fish examined. Many researchers have noted that microplastics are vectors that bridge harmful pollutants to fish and marine life. U.S. health officials estimate that less than 0.3% of microplastics taken into the human body reach the body’s lymphatic and circulatory systems from the gut. And only a very small fraction of these microplastics affect the body’s organs. Still, the effects of microplastics taken into the body on human health are not fully understood.
In 2014, the Ministry of the Environment’s survey on the actual state of marine debris reported that the amount of microplastics in the waters surrounding Japan was 16 times more than in the North Pacific Ocean and 27 times more than in the world’s oceans. And yet, around 2020, major media outlets are only now beginning to report on the issue. Unfortunately, this is one of the topical issues that Japan is still turning a blind eye to. In fact, this is a more serious problem in the world, and we imagine it will be sensationalized soon. We should put some restrictions on countries and companies dumping plastics into the oceans. Japan must be proactive in this regard in order to achieve the SDGs.
In conclusion, we think this title comes from the media’s self-righteousness.
We are not a researcher and cannot say that it is absolutely safe. It is a medium- to long-term issue that should not be neglected with careful monitoring. But in general, Tuna is an expensive food, so it should be economically difficult to consume it in large quantities. Instead, the media should focus on rice, wheat, corn, and other foods that are consumed daily. For your information.
As fish and meat age, their components change, losing their deliciousness while at the same time producing dangerous components that can be harmful to the body. Freshness is determined by the amount of time that has passed since the fish was caught. By knowing the freshness, we can tell how fresh the food is, and at the same time, we can tell if it tastes good and is safe.
However, if they die and are no longer supplied with new ATP, the binding of actin and myosin, the proteins that make muscles stretch and contract, proceeds unilaterally. In combination with the acidification caused by the breakdown of ATP and the formation of lactic acid, the muscles remain contracted. This is the onset of rigor mortis. Finally, ATP is lost and rigor mortis is completed. If a fish dies while its body is exhausted from strenuous exercise, rigor begins earlier than normal. This means that ATP is consumed when fish resist violently to avoid being caught.
K value is a scientific and objective standard for judging the freshness of fish and other products.
To begin with, the postmortem flesh of fish is said to be alkaline. It becomes more acidic over time. In the process of this change, ATP is broken down into several acids as shown below, and the K value is a mathematical formula that captures some of these acids and calculates them.
K value (%) = (HxR+Hx)/(ATP+ADP+AMP+IMP+HxR+Hx)×100
The rate of degradation varies among fish species, but the pathway to HxR is constant. Fish that die quickly after catching have more ATP, ADP, and AMP. Then, as time passes, IMP increases and finally HxR and Hx increase. These HxR and Hx present a tasteless or bitter taste, which causes a decrease in deliciousness. In other words, a high amount of HxR and Hx is evidence of reduced freshness.
In general, fish with a K value of up to 20% can be eaten raw, i.e., as sashimi. In the case of fish, the K value is about 5% immediately after ikejime. 20-40% is considered to be good freshness. Sushi toppings are around 40%, which is not low by any means, but it is at this value that the flavor of the ingredients is most likely to be extracted. In other words, it is a state of maturing and increased IMP. And if it is 40-60%, it is edible if cooked. In other words, it is better to eat simmered or grilled fish. If it is over 60%, it is in a state of decomposition. Naturally, it is not suitable for eating. It is also known that the rate of increase in K value is large for cod and red-fleshed fish, while the rate of increase in K value is small for white-fleshed fish such as red sea bream and flatfish.
Tuna, which is now a representative of high-class fish, was one of the lower ranks of Gezakana (ge means ‘cheap’, and zakana means ‘fish’) in the Edo period. According to an encyclopedia of the Edo period, “maguro is a very vulgar fish, and even common people who live in houses facing the main street would be ashamed to eat it. Maguro was so low-ranked fish that was said to be the food of poor people living in houses on back streets. However, due to the effects of global warming and overfishing, the number of fish called Gezakana has been decreasing. Therefore, meat is definitely cheaper than fish in supermarkets.
Next, please take a look at the ratings of fish in the Edo period as listed in Chiba University‘s study of classical cuisine.
The following fish are listed as Jyozakana (Top-grade fish)
Again, maguro is classified as Gezakana, along with today’s high-end fish such as Kurodai and Fugu, and it seems that most Jyozakana are white fish, and the oily fish, so much appreciated today, was not favored by the people of Edo. In addition, maguro was also called shibi (pronounced “shi,” which is a reference to death), and some believe that it was not popular because it was associated with death.
When large schools of maguro appeared in the seas around Edo (Tokyo) between 1340 and 1844 and were caught in large numbers, they were sold for free because they were not popular.
As a side note, a sushi restaurant made a fortune by purchasing maguro red meat at a low price, marinating it in soy sauce, and selling. This was the beginning of what is now called Zuke.
n this way, red meat was still sometimes preferred, but Toro, which tends to spoil easily, was not looked upon and was often thrown away. Even if it was eaten, it was only in Negima nabe (hot pot) and was rarely eaten raw.
It was not only in the Edo period that toro was not favored.
It was not until the development of refrigeration and freezing technology in the 1945s that otoro and chutoro became as much appreciated as they are today. It is only recently that Otoro and Chutoro have become the kings of fish. Fish grading, in fact, has a great deal to do with safety. Saba, which suddenly loses its freshness, and Iwashi, which is tender and easily loses its freshness, are both Gezakana. In other words, fish that lose their freshness easily were likely to be classified as gezakana.
Another reason was the taste of the Edo people, who preferred light fish such as Amadai, Sayori, and Suzuki to oily fish such as Saba and Buri. It is understandable that Maguro Toro, which is both fatty and perishable, is frowned upon.
The names you’ll hear at sushi restaurants include Itasan, Taisho, Oyakata, Goshujin and Master, etc.
Sushi restaurants generally aren’t strict about this sort of thing, so at an easy-going place probably any of these are acceptable. However, the other customers would probably feel more awkward about what you call the sushi chef than the chef himself. This will be a short lecture about the correct way to address a sushi chef.
First of all, “Goshujin (ご主人)” is used for all shops, is correct Japanese and sounds perfectly normal in both Kansai and Kanto. This title means “shop owner.” However, this is not usually used at sushi restaurants. “Master (マスター )” means the same thing as “Goshujin,” but is mainly reserved for places like bars and cafes and is not used at sushi restaurants.
Another common title is “Itamae (板前)” or other versions of it like “Itasan (板さん),” but these all mean “cook” for Japanese cuisine. Sushi is a type of Japanese cuisine, so calling a sushi chef “Itasan” is not a mistake. However, even amidst Japanese cuisine, sushi requires unique techniques, which sets sushi chefs apart from others.
Itamae learn various Japanese cooking techniques while apprenticing, but actually, they rarely make sushi. Therefore, even if a Japanese cuisine cook were to jump into the sushi industry, they would basically have to start over completely. Furthermore, sushi chefs do not just learn the technique of making individual pieces of sushi, they must also acquire the skill of communicating with customers. My personal opinion is that “Itasan” is a way to address cooks who are employed.
Next, there are customers who say things like, “Taisho (大将), make it without wasabi.” Taisho is a term for shop owners, mainly used in Kansai. However, Taisho is not an appropriate way to address an Edomae sushi chef.
So, what should you call a sushi chef then?!
The correct term is Oyakata (親方). Oyakata refers to a full-fledged, independent chef. We believe sumo stable owners (a position that not just anyone can achieve and requires prior results as a sumo wrestler) are also called Oyakata. This is just for your reference.
Inarizushi is made with only two ingredients: fried bean curd and vinegar rice (or vinegar rice mixed with boiled down carrots, shiitake or similar ingredients). , and it is that simplicity that allows the chef to devote their ingenuity to the dish, creating a unique flavor. It is said to have first appeared at the end of the Edo period, but the origin is uncertain. The shape of Inarizushi differs from that resembling a straw bag in the Kanto and Eastern Japan, where rich sweet and salty flavoring is used, and the triangular shape of Western Japan.
Type of Inarizushi
When categorized based on shape, the types of Inarizushi are bale type, triangle type, open type and roll type. They can also be categorized by the type of rice stuffed into the fried tofu (abura-age): either white vinegared rice or vinegared rice mixed with other ingredients. The four elements that make up the flavor are sweetness, soy sauce, soup stock and acidity, and the balance is very important. In the east of Japan the flavor tends to be a stronger sweet and salty while in the west the soup stock is more apparent.
Here we will explain the characteristics of Inarizushi using categories based on appearance.
Inarizushi seems to be a version of Sugatazushi. Perhaps the Sumeshi is stuffed into the fried tofu instead of into a fish (a hypothesis). When looking at literature from the Edo period, there is Inarizushi in the form of a long rod that was cut up and sold. Someone probably thought that if they were going to cut it up into bite-size pieces anyway, they may as well make it in easy-to-eat sizes in the first place (an inference). There are some shops that still sell Inarizushi in long rod form, but the difference is probably in how the fried tofu is cut. You can find this from Sekigahara, Gifu and further eastward.
Why is the appearance triangular? There are many theories, but the most plausible is that these are meant to be shaped like a fox ear. Inarizushi originated as an offering to the Inari god at festivals. The Inari god is the deity of agriculture and patrons pray to this god at Inari shrines. The head Inari shrine is Fushimi Inari Taisha in Kyoto. Legend has it that fried tofu is a favorite of foxes, who are said to be messengers of the Inari god, so it was made into the shape of fox ears. Another theory is that it is the shape of Mt. Inari where Fushimi Inari Taisha is located. Apparently this is because the triangle type originated at Fushimi Inari Taisha. However, Inarizushi shops in Kansai use lucky bale shapes in order to pray for prosperity in business. On the other hand, Inarizushi made at home or in soba restaurants are usually triangular. This type is found from Sekigahara, Gifu and westward.
The open type is a revolutionary style. How it came about is not clear, but perhaps someone just stuffed it too full of ingredients. Since the ingredients are visible, it looks even more delicious than normal Inarizushi. It’s really beautiful when many are lined up. You can imagine how this served as inspiration to those who went on to add a variety of ingredients. It’s also easy to make since all you have to do is fill it with ingredients. this has already become a staple sushi in France, South Korea, Australia, Singapore and other countries.
Almost all roll-type Inarizushi in Japan is made with a dried fried tofu from Kumamoto called Nankanage. Unlike normal fried tofu, it looks like paper in the shape of a sponge and does not form a bag. That’s why the only way to use it was by wrapping it around the rice. Also, this way of spreading out one sheet of boiled fried tofu and then wrapping the rice inside may have been created as a way to avoid tearing the fried tofu when stuffing with vinegared rice
Ignoring whether or not it is true that carnivorous foxes really love fried tofu, apparently the foxes that serve as messengers to the Inari god do love it. As foxes were thought to be delivering prayers to the Inari god, their favorite fried tofu was given as an offering to stay on the fox’s good side. After that, they started the practice of stuffing rice that was grown with the blessing of the Inari god. As you can see, Inarizushi is the combination of two ingredients involving the Inari god.
There are many things that fall under the term “sushi”.
Within Japan, every prefecture has at least one type of local sushi. In order to understand these different types more deeply, we have separated them into categories and will introduce the typical types.
First of all, there should be rules when categorizing things.
However, there are loads of things in this world that seem to have been categorized without any rhyme or reason. The same thing applies to the words used to express sushi categories and types of sushi. This stems from a complete lack of understanding of the history of sushi and how it is made. However, in the end, sushi is food, so there is no academic dissertation on it. Please consider this to be just one point of view when reading the following.
We will first categorize the sushi with clear rules and then introduce individual sushi.
There are various theories regarding the etymology of the word sushi, but the word stems from “su” which is the kanji for “acid” and means “sour”. Initially, “sushi” was used in Japan to refer to Narezushi*, which is eaten with the natural acidity from fermenting salted fish and white rice together. One of the theories is that it started as Sumeshi (‘su’ means vinegar and ‘meshi’ means rice in Japanese) and the “me” was omitted leaving just “Sushi”. Rice is clearly the main attraction in the word and it is thought this word was used to refer to “Namanarezushi**”, which appeared in a time after Narezushi. Although these are only theories, it can only be called Sushi if sour rice is involved. I don’t believe there is anyone who would dispute this fact.
*Narezushi: Mainly made from seafood, rice and salt, allowed to ferment for three months to one year until the rice no longer maintains its shape. Only the fermented seafood is consumed with this type of sushi. Funazushi from Shiga is a famous example of Narezushi.
**Namanarezushi: It is not allowed to completely ferment (fermentation period of two weeks to one month) so both the fish and rice maintain their shapes. This is when sushi evolved from Narezushi, a dish in which the rice was not eaten, to one where the fish and rice were consumed together. Akita’s Hatahatazushi and Ishikawa’s Kaburazushi are famous Namanarezushi dishes.
The historical turning point of sushi was the emergence of what is called Sumeshi (also called Hayazushi because it can be made quickly), in which the sour taste comes from sprinkling vinegar on the rice (acetic acid), rather than the sour flavor from fermenting (lactic acid) at the beginning of the Edo period. It was Sumeshi that really made variations of sushi catch on. At the time there were only Sugatazushi*** and Kokerazushi**** (the original forms of Hakozushi), but after the middle of the Edo period Makizushi, Inarizushi, Chirashizushi and other types started to appear.
***Sugatazushi: Sushi in which Sumeshi is wrapped into a fish that still has its head intact. Tokushima’s Bouze, Wakayama’s Sairazushi, Kumamoto’s Konoshirozushi and Oita’s Aji-no-maruzushi are examples of this.
****Kokerazushi: Kokera refers to thinly sliced seafood and this sushi is made by stacking Sumeshi and ingredients in a container. This can be found today in Osaka and Kyoto in the form of Hakozushi. Examples include Sabazushi and Hamozushi in Kyoto, Battera in Osaka, Oomurazushi in Nagasaki and Iwakunizushi in Yamaguchi.
Let’s dig a bit deeper and divide these into broad categories.
First of all, Sugatazushi and Kokerazushi are still made today as they were long ago. As one characteristic is that Sumeshi is pressed to fix it in place, it can be categorized as a type of Oshizushi.
Chirashizushi was invented in the late Edo period. When eating something like Kokerazushi in which Ingredients are cut and mixed in with Sumeshi, which is then pressed into a box and held down with a weight, it is cumbersome to scoop it out with a spatula. Chirashizushi is made in the same way but omitting the step of pressing with weights. There are various versions of Chirashizushi all throughout Japan.
There was a customer who complained that Sugatazushi always wrapped around the Sumeshi was dull and suggested wrapping the Sumeshi around the fish instead, which led to the idea of Makizushi. However, as the rice was on the outside, it would stick to fingers, so places located near the ocean started to use things like Nori, Kombu and Wakame to wrap it, while places near the mountains used things like pickled leaf mustard. The core also changed from only fish to include things like Tamagoyaki, Kampyo and carrots. These innovations all took place during the middle of the Edo period.
Inarizushi, in which Sumeshi is stuffed inside of sweet, stewed abura-age is a version of Sugatazushi. When rice crops were bad, Okara (soy pulp) was used for the filling instead. When enjoying plays, a favorite pastime of the Edo period, it became a normal occurrence for commoners to take it as a bento. It is said that it infiltrated the masses because Nigiri sushi was outlawed, but the truth is that no one really knows when it was first invented. It’s now spread throughout the world and has evolved into something that looks entirely different and has different fillings.
It is also important to mention that the method of pressing Sumeshi in Kokerazushi was improved to start with rice made into a bite-sized ball, then sticking the fish on top before placing in a box and pressing, which eventually led to the invention of Nigiri sushi.
Looking back on this information, we can see that most of the types of sushi that exist today were invented during the Edo period. Narezushi and similar dishes prior to that seem to be more like methods to make the meat of fish last a long time, rather than sushi in which rice was part of the meal. And Namanarezushi, where the rice was also consumed but ready-made vinegar wasn’t used, is categorized as “Others” when categorizing present-day sushi.
Another difficult one to categorize is the Uramaki version of Sushi rolls. Uramaki is differentiated from Hosomaki, which is a type of Makizushi. However, it has already far outperformed Hosomaki. The reason is that the ingredients used in Uramaki are mostly things that were never used in Hosomaki, and Uramaki allows for a lot of freedom in method. Now there are also versions that don’t use Sumeshi (although they can be left out of sushi categories altogether). In these versions of Uramaki, the ingredients are clearly the main attraction, rather than the Sumeshi. Therefore, they are considered to be evolved from Hosomaki and should be made into one category. Although Makizushi is generally translated as “Sushi roll”, we will consider them separate categories for our purposes.
There is a debate in Japan as to whether Gunkanmaki is categorized as Nigiri sushi or not. The reason is that Nigiri sushi is made by squeezing (nigiri) Sumeshi in the palm of the hand, while this same squeezing process is not as apparent in Gunkanmaki. Makizushi is made by wrapping Sumeshi around ingredients using a Makisu (Bamboo mat), but Gunkanmaki uses no such thing. Even whether or not the process of adding Nori around the Sumeshi for Gunkanmaki is actually wrapping or not is a bit ambiguous, so it’s not clear if it should be categorized as Makizushi or not. However, the issue is only which category it should be added to and it should not be made into its own category. We will consider it a type of Nigiri sushi as the process does include some light squeezing of the Sumeshi.
While we’re on the subject, it is incorrect to call Sashimi and Seafood bowls types of sushi. There is no Sumeshi involved in Sashimi. Seafood bowls also use normal white rice, not Sumeshi. Hopefully you have a better understanding now.
In conclusion, the biggest point in categorizing is whether it is Sushi that uses Sumeshi made with ready-made vinegar (Hayazushi), or Sushi where the sourness comes from fermentation (Narezushi, etc.). Next, in order to further categorize Hayazushi, it is important to distinguish whether similar methods are used to make it and if the Sushi evolved from another, earlier form of Sushi.
Our results are that seven categories are appropriate for understanding sushi better.
While not often seen in Tokyo, “Whole mackerel sushi” is popular in Kyoto and Osaka. This is pressed sushi made by placing vinegared saba (mackerel) on top of sushi rice and shiroita-kombu (kelp that has been lightly shaved down) on top of that, and is normally called “battera” in Kansai.
It would make sense to call it saba pressed sushi, but a customer actually came up with this weird name, “battera”.
Around 1890, there was an exceptionally large number of konoshiro (gizzard shad) fish for the year. A sushi restaurant took notice of the cheap konoshiro, butterflied it, made it into fukin-jime, then sold it in this shape that resembled a boat. Apparently it used to look more like a boat than the present-day battera.
As the Portuguese word for “boat” is “batela”, someone started ordering by saying things like, “Give me a couple of battera.” Eventually battera became the official name.
Before long, konoshiro hauls dropped and so it was replaced with saba. Also, in order to preserve moisture, sushi chefs started to wrap it in kelp sent by ship from Hokkaido. The shape now is a long, skinny rectangle and it no longer resembles a boat, but the name remains.