Sudachi is small in size with an intense aroma and a sharp, refreshing acidity. In contrast, kabosu contains more juice and offers a milder sourness, giving it a soft flavor that enhances other ingredients without overpowering them. Sudachi is about the size of a golf ball, while kabosu is about the size of a tennis ball.
【Nutritional value of kabosu】
Vitamin C
Citric acid
Potassium
Pinene
Limonene
【Nutritional value of sudachi】
Sudachitin
Vitamin C
Citric acid
Potassium
Beta-carotene
Vitamin E
Calcium
Dietary fiber Polyphenols
At sushi restaurants, these characteristics are carefully utilized. Sudachi is often paired with delicate toppings such as white fish or shellfish, where just a drop can add a refreshing fragrance and highlight the clean flavors of the fish. It is particularly valued when the sushi chef wants the citrus aroma to leave a memorable impression or to give a lighter, fresher finish to the sushi.
Conversely, using sudachi repeatedly in an omakase course can mask the flavors of the sushi toppings.
Kabosu, on the other hand, is chosen when the balance of flavors is more important than fragrance alone. Its gentle acidity and abundant juice make it suitable for richer or fattier fish, grilled items, or simmered dishes, where it softens heaviness and provides an elegant aftertaste.
The appearance of Kikabosu
Aged kabosu (Kikabosu), with its mellow and rounded aroma, is sometimes used to enhance the sophistication of high-end sushi. For example, a light drizzle of kabosu over sushi made with the mild-flavored pen shell (Tairagi) elevates the shellfish to a higher level. Sudachi or young kabosu, however, are too pungent and would merely serve as a simple accent.
In short, sushi chefs distinguish between the two by using sudachi when they want to highlight aroma and freshness, and kabosu when they wish to bring harmony and subtlety to the flavor.
The freezer compartment of a household freezer typically operates at -18°C. However, in practice, due to factors such as how often the door is opened and closed, the temperature often only reaches around -12°C. While this is cold enough to freeze water, it does not freeze the core of the food, so it may appear frozen at first glance. Proteins, enzymes, and lipids remain unfrozen, causing the taste and texture of the food to deteriorate significantly within a few weeks.
On the other hand, ultra-low temperature freezing can freeze all the components of fish meat, suppressing protein decomposition and stopping lipid oxidation. This makes it possible to store food for up to six months. All living organisms begin to age and deteriorate after death, eventually leading to oxidation and decay. The temperature that can stop this process is the world of ultra-low temperature freezing at -42°C.
Inhibition of enzymatic protein degradation
Under normal conditions, proteins that have ceased activity at room temperature undergo enzymatic degradation. For example, the proteins in freshly caught fish are in a high-molecular-weight state. Through enzymatic degradation, they break down into lower-molecular-weight compounds, advancing the aging process. If this process progresses too far, decay occurs.
Additionally, fish have a high water content of 70%, making them age much faster than livestock meat. Therefore, the key is to quickly cool the fish to ultra-low temperatures after catching them and then thaw them while maintaining the aging process.
Inhibition of fat oxidation
What is commonly referred to as “freezer burn” occurs when the fat naturally present in food rises to the surface and oxidizes, causing the color to turn yellowish and the appearance and taste to deteriorate. To prevent this, it is essential to prevent the food from coming into contact with air. Furthermore, by storing it in an ultra-low temperature environment, the oxidation process itself can be almost completely halted.
Inhibition of microbial proliferation
Even at the -18°C environment of a household freezer, microbial proliferation can be largely suppressed. However, for complete inhibition of all types of microbial growth, ultra-low temperatures are ideal.
Real-world applications
Ultra-low temperature freezing is already widely used in the seafood industry. At Tokyo’s Toyosu Market, premium tuna is stored and transported at -60°C to preserve its deep red color, fatty texture, and fresh taste for overseas shipments. In Hokkaido, Pacific saury is frozen at -50°C immediately after being caught on specialized vessels, allowing them to be enjoyed months later with near-fresh quality. Some Japanese supermarket chains use -45°C freezing for salmon fillets, enabling them to offer sashimi-grade products all year round while minimizing quality loss.
In sushi restaurants, anago (saltwater eel) is often purchased in bulk when prices are stable, stored at ultra-low temperatures, and thawed to maintain quality and cost efficiency. Likewise, ikura (salmon roe) is typically prepared in autumn, its peak season, and frozen for year-round use, ensuring consistent flavor and texture regardless of the season.
The fact that a 10,000-year-old mammoth excavated from Siberian permafrost was still edible after being cooked is a testament to the capabilities of ultra-low temperatures.
At first glance, Ikura and Sujiko look quite similar — both are salmon or trout roe — but they differ in preparation, flavor, texture, and how they are eaten. Here’s a closer look at their differences.
What is Ikura?
The word ikura comes from Russian, meaning “fish roe” or “small grains.” In Russia, it can refer to various types of roe, including caviar and cod roe. In Japan, however, ikura generally refers to salmon or trout roe, and in the fishing industry, it often means only salmon roe.
Ikura is made from mature salmon roe that is removed from the egg sac, separated into individual eggs through a mesh, and then seasoned — typically with salt or soy sauce. The grains are large, bursting in the mouth with a satisfying “pop,” releasing rich, buttery flavor. Because of its beautiful appearance and texture, ikura is commonly used for sushi, rice bowls, and various appetizers.
What is Sujiko?
Sujiko is made from immature (Not just before laying eggs) salmon roe that is salted while still wrapped in the membrane of the ovary. The eggs remain connected like a string (suji: 筋 in Japanese), which is where the name comes from. Since the eggs are less mature, the grains are smaller than those of ikura, and the texture is more dense and creamy.
There are two main ways to season sujiko:
Traditional salting (塩漬け) – The roe is salted to draw out umami, then salted again to finish the process. Freshness is critical; roe processed immediately after the fish is caught will be less salty and have better texture, while roe processed later will taste saltier and lose some texture.
Soy sauce marinating (醤油漬け) – A modern method that uses soy sauce which does not darken the roe, preserving its bright red color.
Historically, sujiko was considered a very salty preserved food and was thought to pair poorly with vinegared rice, so it was rarely used in sushi. However, with the rise of low-salt and soy sauce–marinated sujiko, it has started to appear in sushi and other creative dishes.
Texture – Ikura: bursts in the mouth / Sujiko: creamy and dense
Use – Ikura: sushi, donburi, appetizers / Sujiko: rice topping, onigiri, and now occasionally sushi
Both ikura and sujiko are symbols of autumn in Japan. Knowing the differences will help you appreciate their unique qualities — and choose the perfect roe for your meal.
Koku is a comprehensive sensory experience derived from the combined stimuli of taste, aroma, and texture in food. It refers to a phenomenon characterized by the complexity of these stimuli, further enhanced by a sense of spatial expansion and lingering persistence.
Just as taste is defined by the five basic categories of sweetness, saltiness, bitterness, sourness, and umami, Professor Toshihide Nishimura of Kagawa Nutrition University explains that koku can also be described through three fundamental elements: complexity, mouthfulness, and lingeringness.
While these three terms are individually recognized internationally in relation to flavor, there is no direct English equivalent that fully captures the nuance of the Japanese concept of koku when these elements are combined.
The first element, complexity, can be objectively evaluated based on the diversity of chemical compounds present in a food. For instance, fermented foods like soy sauce and miso develop hundreds of additional compounds as they age—meaning a batch aged for two years will typically have much greater complexity than one aged for only one year. Similarly, foods that are cooked for extended periods, such as stews, tend to develop a more intricate flavor profile due to the formation of a wider range of substances, which enhances the sense of koku.
The second element, mouthfulness, is closely tied to retronasal aroma—the aroma that travels from the back of the throat into the nasal cavity during chewing and swallowing. Retronasal aroma plays a critical role in how we perceive flavor. This becomes particularly evident when we catch a cold: with nasal congestion impairing our sense of smell, foods suddenly seem flavorless. In fact, the olfactory system is considered more advanced than the gustatory system in distinguishing fine differences. For example, when chewing vinegared rice, the aromas of vinegar, kelp broth, and seaweed gradually rise through the back of the throat into the nasal passages. Aromatic molecules linger on the mucous membranes of the nasal cavity, allowing the brain to continue interpreting them as part of the overall taste experience.
The third element, lingeringness, is often enhanced by the presence of fat. Fat readily absorbs and retains aromatic compounds, allowing them to adhere to the mucous membranes of the tongue and nasal passages, thus prolonging the flavor experience. While we often describe fatty foods as “rich and flavorful,” it’s important to note that fat itself is tasteless and odorless. The perceived flavor comes from the wide range of compounds that dissolve into the fat during cooking, creating a complex and lasting impression.
However, not all taste and aroma compounds in food are present at concentrations high enough to be consciously perceived. Here, the concept of a threshold becomes crucial—the minimum concentration at which a compound can be detected by the senses. Many flavor and aroma molecules exist below this threshold. While they are not individually detectable, they interact synergistically with other components to subtly but significantly shape the overall flavor impression.
These undetectable compounds function like hidden flavors. Rather than asserting themselves directly, they enhance the definition of other flavors and contribute to a balanced and harmonious profile. In this sense, they can be considered koku-enhancing substances that strengthen the depth, complexity, and persistence of the taste experience.
For example, a small amount of yuzu peel added to miso soup, a pinch of salt concealed in a simmered dish, or the synergistic effect of glutamic acid and inosinic acid in kelp-based broth—all of these contribute not through obvious presence, but by shaping the overall flavor, expanding the taste on the palate, and enriching the lingering aftertaste we associate with koku.
Thus, koku is not simply a “rich flavor” but a nuanced sensory phenomenon created by the interplay of clearly perceptible and imperceptible flavor elements. It emerges from thoughtful ingredient selection, careful cooking techniques, controlled aging, and subtle enhancements such as “secret ingredients.” All these components work together to create a dish with true koku.
This is why koku is so difficult to translate directly into English. It is not just a taste, but a layered sensory experience with temporal and spatial dimensions, lying at the very heart of Japanese cuisine. Understanding koku provides valuable insight into the richness of Japanese culinary culture and the refined craftsmanship that brings its flavors to life.
Besides anago, nitsume is brushed onto sushi toppings that have been simmered in a flavorful liquid, like shako and hamaguri.
In Japanese culinary terms, “nitsumeru” (verb) refers to the process of reducing the liquid content of a sauce containing seasonings by boiling off the moisture, thereby concentrating the flavor and increasing its thickness. Both “eel sauce” and “conger eel nitsume” are sauces made by reducing the liquid content through boiling.
First, you need to understand the difference between eel and conger eel.
In Japanese, the word “unagi” generally refers to a freshwater eel. The scientific name is Anguilla japonica Temminck & Schlegel, 1846. On the other hand, the word “anago” generally refers to the conger eel. Its scientific name is Conger myriaster (Brevoort, 1856).
While both eel sauce and conger eel nitsume are made by reducing liquid through boiling (the process known as nitsumeru), only the latter is traditionally referred to as “nitsume” in sushi restaurants.
So, what is the fundamental difference between them?
Eel sauce (known as unagi sauce or unagi no tare) is a rich, sweet soy sauce-based sauce that is ideal as a dip or drizzling sauce. It does not actually contain any eel ingredients, but it is a sweet, sticky sauce that is perfect as a topping for sushi rolls and other dishes.
“Eel sauce” can refer broadly to both mass-produced sauces and artisan sauces made by eel restaurants. The basic method for making eel sauce is to mix mirin and soy sauce and heat it. Various ingredients such as sake, sugar, tamari soy sauce, water amber, honey, dashi, and potato starch (commercial products often contain thickening agents) are added to create a unique flavor.
Incidentally, most traditional eel restaurants make their eel sauce using only high-quality mirin and soy sauce. This gives the eel a beautiful glaze and subtle sweetness when grilled, as well as a clean aftertaste, which is why it is considered a craftsmanship.
When making kabayaki, the process of applying eel sauce is repeated multiple times. The components of the eel sauce combine with the umami of the eel to create a deeper, more complex flavor. In addition, applying the sauce and grilling it causes chemical reactions such as the Maillard reaction and caramelization, which further enhance the appetizing flavor.
While you can easily buy eel sauce at the market, it’s incredibly easy and tasty to make at home. Eel sauce can be used as a seasoning for other dishes if there is any left over, but it is primarily a sauce specifically made for making kabayaki. By the way, kabayaki is a fish dish where the long-bodied fish is filleted, the central bone removed, skewered, grilled, and then coated with a thick sauce before being grilled again. In Japan, when people say “kabayaki,” they are usually referring to “unagi kabayaki.” Other ingredients used include hamo and anago.
Nitsume is brushed onto nigiri sushi made with anago, shako, shellfish, and other toppings. In sushi restaurants, it is often abbreviated as “tsume.” There are several methods for making nitsume, including reducing the cooking liquid from simmered conger eel, or simmering the head and bones of conger eel to extract the broth, then adding seasonings and reducing it further. In other words, nitsume contains components of conger eel.
Compared to anago, unagi is more flavorful, fatter, and meatier. Moreover, unagi is considered a higher-quality delicacy in Japan and is therefore more expensive. In terms of taste, unagi has a richer, more intense umami flavor. The common opinion is that anago, because of its lighter taste, harmonises better with soured sushi rice and is therefore the preferred choice for making nigiri sushi.
As a side note, while nigiri sushi with eel is common in the Kansai region, eel is not used as a sushi topping in Edomae sushi. Therefore, Edomae sushi restaurants do not serve unagi nitsume.
In summary, unagi (eel) sauce is made by eel restaurants, while anago (conger eel) nitsume is made by sushi restaurants. Eel sauce does not contain eel components, while conger eel nitsume contains conger eel components.
Sujime (酢締め) is a traditional preparation method in which fish is first salted to draw out moisture (Shiojime) and then lightly marinated in vinegar. It is widely used as a sushi topping.
However, the techniques used for Sujime today differ significantly from those of the Edo period. Differences include the amount of time the fish is left with salt and the duration it is soaked in vinegar. Until around the 1980s, it was common practice to soak fish such as mackerel and horse mackerel in vinegar for an extended period. In modern times, thanks to advanced refrigeration technology, fish such as horse mackerel (aji) can now be eaten raw without concern. As a result, the time the fish is salted has been shortened to just a few minutes. Once moisture begins to appear on the surface, it is carefully rinsed off with water. Rather than soaking in vinegar, the fish is quickly dipped, more like a gentle rinse. The goal is to retain the natural flavor of the fish, requiring a delicate and refined touch.
Fish suitable for Sujime are those with a robust umami flavor and a distinctive aroma that can stand up to the acidity of vinegar. Typical examples include blue-backed fish like mackerel, Spanish mackerel, sardines, and gizzard shad. Depending on the case, white-fleshed fish such as barracuda, red seabream, and filefish may also be prepared as Sujime.
There are three main reasons why Sujime is used in sushi restaurants.
The first is preservation. Vinegar has strong antibacterial properties, and before the advent of refrigeration, Sujime was a way to prevent spoilage and extend the shelf life of fish. Vinegar kills bacteria on the surface of the fish, helping to keep it hygienic. Even today, in sushi where raw consumption is the norm, Sujime remains valuable for enhancing food safety.
Second, Sujime plays a key role in reducing unpleasant odors and refining flavor. Blue-backed fish are rich in fat, particularly unsaturated fatty acids found between the skin and flesh. These fats are prone to oxidation, which can cause a strong fishy smell. Additionally, the flesh of fish contains trimethylamine oxide, a naturally odorless compound that, over time and through bacterial action, turns into trimethylamine, which has a strong odor. Eventually, ammonia is also produced, intensifying the smell. Since Trimethylamine is alkaline, treating the fish with acidic vinegar neutralizes it, effectively reducing odor. A quick dip in vinegar removes unwanted smells and balances the umami and acidity, resulting in a more refined taste.
The vinegar causes the proteins in the fish to denature.
Finally, Sujime enhances both the flavor and texture of the fish.
When vinegar is added to fish, the proteins are denatured. The pH of fresh raw fish is around 6, but when it is into vinegar and the pH becomes more acidic. The gaps between the myofibrils decrease because of vinegar, tightening the flesh. This creates a texture and mouthfeel distinct from raw fish.
As the pH continues to drop below 4, the myofibril protein starts to dissolve in the acid, so the flesh becomes soft and mushy. But if the fish is salted and tightened before putting it in vinegar, the myofibrils do not dissolve and remain intact, so the flesh continues to tighten. This is why vinegared- marinated fish looks white.
Furthermore, the acidity of vinegar stimulates the taste buds on the tongue, creating a synergistic effect that brings out sweetness and umami. Even with a short vinegar marinade, a mature aroma and depth are added, giving blue-backed fish such as kohada and mackerel a deep, “mature flavor.”
Sujime is not merely a preservation technique; it is a skilled process that brings out the best qualities of the fish. It is one of the key steps in refining the sushi experience to perfection.
Namero (なめろう) is a traditional local dish from the coastal areas of the Bōsō Peninsula in Chiba Prefecture, which faces the Pacific Ocean.
This region has long been blessed with an abundance of fresh seafood, especially horse mackerel (aji), available year-round.
Originating as a fisherman’s meal, namero was devised to be easily prepared on the unsteady decks of fishing boats, making the most of freshly caught fish.
Main Ingredients and Preparation
The basic recipe involves finely chopping horse mackerel together with miso, green onions, ginger, and sometimes shiso leaves,
then mincing everything together until it becomes sticky and paste-like.
While horse mackerel is commonly used, other blue-backed fish such as sardines, pacific saury, flying fish, yellowtail, and even squid or bonito
are also popular depending on the season and locality.
The use of miso instead of soy sauce has a practical origin—it’s less likely to spill on a rocking boat.
The miso also helps neutralize the strong aroma of oily fish, enhancing only their natural umami flavors.
It is said the name “namero” comes from the phrase “so delicious you’ll want to lick the plate clean.”
Another theory is that the sticky texture makes it hard to scrape off the plate, so you’d have to “lick” it off to finish it.
Misconceptions and Variations
Namero is sometimes confused with “tataki (タタキ),” another chopped fish dish, but they are quite different.
Tataki is usually lightly chopped and often uses soy sauce and vinegar, whereas namero is more thoroughly minced and flavored with miso,
creating a smoother and more cohesive texture.
Over time, regional variations and creative adaptations of namero have emerged.
One notable example is sanga-yaki (山家焼き), a grilled version of namero.
Legend has it that fishermen used to pack leftover namero into abalone shells and grill it in mountain huts while working inland—hence the name “sanga,” meaning “mountain house.”
Another beloved version is “mago-cha (まご茶)” (literally, ‘grandchild tea’), a rustic ochazuke-style dish where namero is placed on hot rice and doused with warm dashi broth.
The name has two possible origins: one being that the dish could be eaten quickly without hesitation (“mago-mago” meaning to fumble),
and the other being that it’s so tasty you’d want to share it with your grandchildren.
The addition of dashi slightly cooks the fish, offering a delightful change in texture and flavor.
Conclusion
Namero is a dish that truly captures the culinary heritage of coastal Chiba, transforming simple, fresh fish into a flavorful and nutritious meal.
With its wide adaptability, regional roots, and deep umami taste, it continues to charm both locals and visitors alike.
Today, it is served as a tsumami (appetizer) in izakayas and sushi restaurants.
Whether enjoyed raw, grilled, or as a comforting bowl of ochazuke, namero remains a timeless symbol of Japan’s rich seafood culture.
Arai is a traditional Japanese sashimi technique in which raw seafood is rinsed in cold or ice water. Also known as “洗鱠” or “洗魚”, this method is especially popular during the summer months for its refreshing taste and texture.
How Arai Is Prepared
In this technique, thinly sliced or shredded fish is placed in a strainer set over a bowl of ice water and washed until the flesh firms and warps. Some chefs also use running water for the rinsing process. The purpose of this rapid chilling is to stimulate the muscle fibers, causing them to contract and tighten, resulting in a firmer texture and improved mouthfeel.
Benefits of the Arai Method
Washing the fish removes surface proteins and lipids, effectively reducing unwanted odors—often caused by the oxidation of fats—and producing a cleaner, lighter taste. Arai is especially well-suited for seafood that has a strong aroma, high fat content, or soft flesh.
Common Seafood Used in Arai
Freshwater fish: Carp (koi) is the most well-known example.
Shrimp: Live kuruma shrimp are sometimes rinsed instead of served raw, offering a firmer texture than odorigui (live sashimi).
Saltwater fish: Japanese sea bass (suzuki), black sea bream (kurodai), and redspotted grouper (akou or kijihata) are commonly prepared as arai to remove their pungent coastal aroma (known as iso-kusasa).
Historical Context
During Japan’s period of rapid economic growth in the postwar Showa era, marine pollution led to concerns about fish having a “petroleum-like” odor. Suzuki was especially affected and often prepared as arai to mask the smell. This historical context helped establish Suzuki no Arai as a quintessential seasonal summer dish in Japanese cuisine.
Freshness Is Essential
Fish used for arai must be extremely fresh and ideally still alive at the time of preparation. After death, fish rapidly lose ATP (adenosine triphosphate), the energy molecule responsible for muscle contraction. Once ATP is depleted, rinsing in cold water no longer causes the muscle fibers to contract, rendering the technique ineffective. The act of washing forcibly removes ATP and induces contraction, resulting in a firmer texture.
A Seasonal Delicacy
The brief rinsing also helps wash away surface fat, balancing the richness of fatty fish and resulting in a crisp, clean flavor. This quality makes arai not only a method of preparation but also an expression of culinary seasonality and refinement, offering a moment of cool relief during Japan’s hot summer months.
Tataki refers to a Japanese cooking method or the dish itself. Among its many variations, Katsuo no Tataki (seared bonito) is by far the most well-known. While the term tataki is also used for dishes made with other ingredients—like meat or vegetables—the preparation method and meaning can vary slightly depending on the context.
The appearance of Katsuo tataki
A Specialty of Kochi Prefecture
Katsuo (bonito), the official fish of Kochi Prefecture, is a beloved local staple. The origin of Katsuo no Tataki is said to lie in the humble meals eaten by fishermen aboard their boats. In times before refrigeration, they developed this method to make slightly aged bonito palatable. Lightly searing the fish helped reduce its fishy odor and enhanced its flavor.
Today, tataki has become a regional specialty. In Kochi, it’s not limited to bonito—local versions include moray eel, meats, shiitake mushrooms, pumpkin, and eggplant, all prepared in a similar style.
How It’s Made—and Why It’s So Good
The key to Katsuo no Tataki lies in its bold yet balanced preparation. Fresh bonito is scaled and filleted into five pieces, then quickly seared on the outside—traditionally over a strong flame fueled by straw. This high-heat method chars the skin, adding a smoky aroma, while keeping the inside rare and tender, like sashimi. After searing, the fish is rapidly cooled in ice water to stop the cooking and firm up the texture.
It’s then sliced and served generously topped with aromatic condiments like green onions, grated ginger, or shiso leaves. Ponzu, a citrus-based soy sauce, is often poured over the top. The contrast between the crisp, smoky exterior and the soft, raw interior creates a mouthwatering harmony of flavors and textures.
“Shio Tataki”: A Kochi Original
The appearance of shio tataki
In Kochi, there’s also a beloved variation called “Shio Tataki” (salt tataki). Instead of ponzu, the seared bonito is simply seasoned with salt—but what truly defines this style is the generous use of raw garlic slices. Typically, two or three slices are placed on each piece of fish. The bold combination of salt and garlic enhances the natural flavor of the bonito, making it incredibly delicious. Garlic also provides antibacterial benefits, which adds a functional layer to its use as a condiment.
The Meaning of “Tataki”
Many people assume that Tataki refers only to fish that’s been seared with straw, but the term originally comes from the act of “tataku” (to pound or slap). In earlier times, when seasonings like soy sauce and salt were expensive, fishermen’s families would rub a small amount into their hands and pound it into the fish to make the flavor penetrate more deeply. That technique—literally pounding the seasoning in—is where the name Tataki comes from.
Even today, after searing and chilling the fish, it’s firm and tightly textured, making it difficult for sauces to soak in. To solve this, the fish is gently pounded with a knife or by hand to help the seasoning absorb. This step is essential and preserves the original spirit of tataki preparation.
Why Straw-Firing Matters
Why is straw preferred over wood for searing? Straw contains natural oils, which produce an intense flame when burned. This allows the fish’s surface to be seared in just seconds, keeping the inside rare—perfect for tataki. Moreover, the fragrant smoke from the straw infuses the fish with a uniquely appealing aroma. The high heat also helps remove excess moisture, concentrating the flavor and improving the texture.
In addition to flavor, searing the surface plays a practical role: it reduces the risk of food poisoning or parasites, making the dish safer to eat.
A major cause of poor performance by sushi restaurants is that the seafood they purchase remains unsold. Instead of being served to customers as sushi or sashimi, it begins to rot and is discarded. When this situation persists, people resort to things they should not do.
It is used as a freshness preservative to extend shelf life because it prevents oxidation of perishable items by absorbing oxygen in a sealed condition. It is used to prevent the deterioration of pharmaceuticals, clothing, cosmetics, etc., so it is not a suspicious chemical, but it is used in the wrong way.
On the other hand, a factor that significantly increases performance is the use of ingredients purchased at low prices and served as overpriced dishes. For example, a food fraud is to offer a lumpfish caviar as a Beluga caviar. This is like exchanging a $1 bill for a $100 bill.
Those who believe in the goodness of human nature may find it hard to accept that such things are happening, but please take a look at the survey results below.
Oceana, a marine conservation organization, previously released a study that found that approximately 60% of supermarkets and restaurants that sell seafood in New York City had some seafood that was different from the product name. The survey involved DNA analysis of 142 seafood samples from 81 supermarkets, food stores, restaurants, and sushi restaurants in New York City. According to the survey, sushi restaurants were found to have the most fish samples that differed from the product names (76%), followed by restaurants (39%), and supermarkets and food stores (29%). The most common type of fish found to be different from the actual product was white tuna. Of the 17 samples of white tuna brought back from sushi restaurants, 16 or 94% were Escola.
By the way, what kind of fish is white tuna in this survey? White tuna does not exist. In Japan, Yake maguro, which died after being caught violently on longlines, is sometimes called so.
Overseas, however, this does not seem to be the case. Often marketed as “white tuna” or “super white tuna,” this is the common name for two species of fish, Escolar (Aburasokomutsu) and Oilfish (Baramutsu). The flesh of Escolar (Aburasokomutsu) and Oilfish (Baramutsu) are rich in taste and can be substantially cheaper than that of other fish species, leading to some vendors intentionally mislabelling it as Butterfish or Cod.
Escolar contains a waxy ester called gempylotoxin which makes up to 90% of the fish’s total fat content and gives it its characteristic texture. Despite its name, gempylotoxin is not poisonous. However, humans can’t digest this waxy substance, and consuming it can lead to stomach cramps, intestinal discomfort, and an unfortunate encounter with the toilet for some individuals.
Oilfish (Baramutsu) has been banned by the Ministry of Health, Labor and Welfare in Japan since 1970 as a food that falls under the Food Sanitation Law and is not distributed. Escolar (Aburasokomutsu) is also a member of the same family, and its sale is prohibited under the same law.
Escolar and Oilfish are sold in supermarkets and is therefore an edible fish in the U.S. and other countries.
In South Korea, where it has been consumed as white tuna, there was a move to amend the law to prohibit its consumption, but it has continued to be distributed disguised as tuna since then. In China, some companies offer this species disguised as salmon and cod. In Taiwan, on the other hand, there are no restrictions on distribution, and the fish is eaten as sashimi. Of course, in the U.S. and other countries, it is sold in supermarkets and is therefore an edible fish.
In other words, the only problem is that cheap fish is disguised as tuna to sell it at a higher price.
The green paste on top of the sushi topping is Atarinegi.
If you are wondering what this term means, you must have had quite a few sushi and Japanese cuisine experiences. Only a few sushi chefs use the word. This may be since the sushi chef who first invented the condiment did not give it a name. Still, it is a very stylish word, so we will explain it in detail.
The appearance of Suribachi
Suribachi (grinding bowl or mortar) is a tool used to crush food. It is widely known to the Japanese public as suribachi. In Japanese culinary circles, the first half of the word suri is avoided and replaced with the word atari. The Japanese word “Suri” means to steal something from someone else’s pocket or wallet quickly in a crowd. It also refers to the person who steals it. In other words, the chefs use the word Ataribachi (当たり鉢) instead of Suribachi (擂鉢).
As a side note, food processors have recently replaced the Ataribachi, but the smoothness of dough prepared in an Ataribachi (grinding bowl) produces a delicious taste that cannot be discarded and has a mouth feel that can never be achieved with a food processor. It is an indispensable cooking utensil for chefs.
Back to Atalinegi. First of all, negi means spring onion, which you know. And atari, as mentioned above, means to grind food in a grinding bowl. In other words, the original meaning refers to a condiment made from ground green onions.
However, in sushi restaurants, the green paste-like condiment found on Horse mackerel (Aji) or Bonito (Katsuo) is sometimes called Atarinegi. It is a condiment that brings out the flavor of Horse mackerel and Bonito even more.
Asatsuki has the most pungent flavor of all leeks, and its leaves are bright green and fragrant.
Atarinegi is made by grinding Asatsuki (Japanese chives) in a grinding bowl until it becomes sticky, then adding squeezed ginger juice. Asatsuki is the most pungent of all edible green onions, and its leaves are bright green and fragrant. Its taste, strange as it may seem, becomes very close to garlic. In Kochi, garlic chips are added to Bonito, so perhaps there is magic in the combination of fish and garlic.
Sushi items such as horse mackerel and sardine have traditionally been topped with spring onion and ginger.
And some sushi chefs have appropriated the name Atarinegi for this condiment. It is so-called Jargon, so that is not the Jargon that all sushi chefs use. This is more common because spring onions and ginger have been placed on top of Nigiri such as Horse mackerel and Sardine for a long time. It counteracts the distinctive fatty smell and enhances only the flavor of the fat, but it requires a lot of spring onions and ruins the appearance of the Nigiri sushi. Therefore, the change to Atarinegi may have been made in order to reduce the amount of spring onions. Shuzou Okada (岡田周三) is said to have invented Atarinegi.
The quality of soy sauce is determined by its clear reddish-brown color.
By the time you know some of the jargon used in sushi restaurants, you are already fully immersed in the world of sushi. The first jargon you will probably learn is Murasaki. Jargon is a word, phrase, or jargon that is understood only among certain professionals and their peers, so it is used among people who work at sushi restaurants. It is not used by customers, of course.
Now, what does Murasaki mean in a sushi restaurant? Actually, “Murasaki” is a jargon for soy sauce. So, we did some research to find out how soy sauce came to be called Murasaki. Originally, soy sauce was a food culture of the late Edo period, so there should be plenty of documentation of its use. However, even after researching, ” Murasaki ” ‘s origin was unclear. There are various theories, but here are some of them.
There is a theory that soy sauce has the alias “Murasaki” because of soy sauce’s reddish-brown color.
In ancient and medieval times, the reddish-brown color was called “purple” in Japan, and the color of soy sauce dropped on a small plate was reddish-brown, which is why soy sauce was called “Murasaki” in Japan.
This may seem surprising since soy sauce appears to be black. Generally, dark soy sauce has a clear reddish-brown color. If you put it in a glass or something and look at it through the light in a bright place, you will see it has a beautiful reddish color.
Some people believe that the alias “Murasaki” for soy sauce comes from purple being a noble color.
During the Edo period, although Edo became the political center of Japan, it still lagged behind Kyoto, Osaka, and other cities in the Kamigata region in terms of culture. The leaders of the Edo shogunate, who wanted to build a unique culture in Edo, apparently conceived the idea of making purple, which had long been considered a symbol of nobility, the symbolic color of Edo culture. It is said that the 8th shogun, Yoshimune, had purple dye studied in the Edo Castle.
It is also known as Edo purple (Edomurasaki), the color of the headband that the main character wears in popular Kabuki performances. There is no reason why the Edomurasaki color used by actors in Kabuki, the greatest entertainment of the Edo period, should not be popular. Edomurasaki is also known as the color that symbolizes the aesthetic sense of the chic Edokko, characterized by its deep blue tone in contrast to the reddish Kyoto purple (Kyomurasaki).
In this way, purple culture grew up in Edo. It is widely believed that this cultural background and the fact that dark soy sauce, which was an expensive and precious seasoning at the time, was almost purple, gave rise to the alias Murasaki. As a synonym for “precious,” dark soy sauce in the Kanto region came to be called Murasaki.
Some people believe that Murasaki, another name for soy sauce, comes from the black soybeans of Tamba.
Tanba no kuromame are large, high-grade soybeans originating from the Tanba region of Hyogo Prefecture. It is said that the name “Murasaki” was derived from the purple color of soy sauce made from these black beans.
There is a theory that the name “Shihou” (It means purple mountain) is derived from the elegant name for Mount Tsukuba.
Shihou is said to have originated from the purple color of the surface of the mountain when illuminated by the setting sun. It is also speculated that purple was an appropriate color for Mt. Tsukuba, which has also been revered as a sacred mountain. The theory is that soy sauce was produced in large quantities near the foot of Mt. Tsukuba during the Edo period, giving soy sauce the alias “Murasaki”. Shihou (紫峰) is also used today in the Shibanuma shoyu brand located at the foot of Mt. Tsukuba.
Finally, it is said that soy sauce came to be called Murasaki actually after the Meiji period (1868-1912). If this is correct, the second theory seems to be wrong. Many soy sauce manufacturers have been around since the Edo period, but their websites do not mention the origin of Murasaki at all. It is Jargon after all, so it is not for outsiders to make claims. In addition to Murasaki, one should avoid using Agari (which means three things in Japanese: Green tea in a sushi restaurant, dead fish, and a finished dish), Oaiso (Check), Namida (Wasabi), and Aniki (sushi material that has been prepped first, i.e., old).
Anisakis is usually found on the surface of internal organs, but can also appear on the surface of the fish.
Anisakis is a parasite of fish and shellfish, including mackerel, horse mackerel, sardines, bonito, squid, cod, saury, flatfish, and salmon. Three groups of parasites, Anisakis simplex, Anisakis physeteris, and Pseudoterranova decipiens, are considered to cause Anisakis disease in Japan. Larvae are elongate, 2~3 cm long and 0.5~1 mm wide, and most are translucent white. The species of Anisakis parasitizing fish and shellfish vary depending on the species of fish, the sea area, and the habitat depth.
Anisakis spawns as adults in the stomachs of whales and other marine mammals. When the eggs are excreted with feces, they hatch in seawater, and the larvae are eaten by krill, where they remain as larvae in the krill-eating seafood. Food poisoning occurs when people eat fish and shellfish parasitized by these larvae.
Three to four hours after infection, symptoms such as upper abdominal pain, nausea, and vomiting appear. These symptoms are now known to be an allergic reaction to the stomach wall and the Anisakis, rather than direct pain caused by the Anisakis piercing the stomach wall.
Mackerel is the most common type of Anisakis disease case reported in sashimi and sushi. In Tokyo, more than half of these cases are caused by Shimesaba (vinegared mackerel). When serving ingredients such as sashimi, chefs need to look carefully with their eyes to see if Anisakis is present and to remove the internal organs. Anisakis may not be visible, so care should be taken. The food items should not be served as sashimi if they are visible.
Anisakis larvae are parasites primarily on the surface of internal organs. They do not move from the internal organs if the fish is cold and near iced, but they may move into the flesh as the fish loses freshness or over time. For this reason, when purchasing (catching) and bringing home, it is important to keep the fish cold with ice or refrigerant to prevent loss of freshness. However, it is important to note that some species of fish, such as Chum salmon (Sake), have Anisakis lurking in their entire body. Sushi chefs know this and do not use it in Nigiri sushi. In addition, it has been hoped that soy sauce, wasabi, and vinegar may be effective in preventing Anisakis disease. However, the insect bodies are not killed by the amount and concentration used in cooking and the time of treatment.
How to Prevent Anisakis
In 1968, the Netherlands mandated by law that herring to be eaten raw in vinegar be frozen at -20 ºC or lower for at least 24 hours before cooking, drastically reducing the number of anisakiasis cases. The U.S. FDA recommends that fish for raw consumption be frozen at -35 °C for 15 hours or at -20 °C for 7 days, while EU health management standards require visual inspection of marine fish for parasites. The EU standard requires visual inspection of marine fish for parasites and directs freezing treatment (at -20 °C or below for at least 24 hours) for marine fish intended for raw consumption. In Japan, heat treatment at 70 °C or higher or 60 °C or higher (for about 1 minute) and freezing at -20 °C or lower for 24 hours or longer are supposed to kill the parasites.
New Technology for Killing Anisakis
Japan Seafoods, a seafood processing company, and Kumamoto University’s Institute for Industrial Nanomaterials Research have jointly developed a method and device to kill Anisakis by using an instantaneous electric power like lightning to kill them in fish meat. The establishment of a new method of killing Anisakis without heating has brought the risk of food poisoning from Anisakis on non-frozen raw sashimi closer to zero. However, challenges remain, such as downsizing the equipment and reducing costs.
Red fish cannot be distinguished even by fish professionals when filleted.
Red fish is a common name for several species of fish. In Japan, it is most commonly applied to certain deep-sea rockfish in the genus Sebastes. Red fish means the word ‘Akauo’ (赤魚). ‘Aka’ (赤) is red, and ‘uo’ (魚) is fish.
Since there are numerous red looking fish, Splendid alfonsino (Kinmedai) and Broadbanded thornyhead (Kichiji) may also be considered Akauo.
Originally, Akauo referred to Akoudai (Sebastes matsubarae Hilgendorf, 1880). This fish is in season during the winter. It was once used as a substitute for Madai or Pacific cod (Madara), but in recent years its catch has declined dramatically and it has become an ultra-premium fish. It is also caught in the Kanto area and is still caught in Tokyo Bay. The term “Akou” for short refers to red-spotted grouper (Kijihata), which is quite confusing. Besides, Akauo is also the standard Japanese name for a species of goby family.
In most cases, the fish sold in the market as Akauo are Pacific ocean perch (Arasukamenuke) and golden redfish (Taiseiyouakauo), which are closely related species frozen and imported from Alaska and Russia. The flesh is white without any particular flavor, and is widely used in dishes such as miso zuke, kasuzuke (pickling in sake lees), shioyaki (grilled with salt), and simmered. Pacific ocean perch (Arasukamenuke), which is caught in the waters around Japan, is also used in Nigiri sushi.
In any case, there is no doubt that red fish is a delicious fish.
＊Sebastes norvegicus (Ascanius, 1772) and Sebastes marinus (Linnaeus, 1758) are the same species.
Modori-gatsuo are those that migrate southward from off Sanriku to the Boso Peninsula from mid-September to late October.
In Japan, bonito is called variously Hatsugatsuo, Modorigatsuo, Mayoigatsuo, Netsukigatsuo, and so on. The quality of the fish is unique depending on the season and size, and bonito lovers will be able to enjoy a variety of flavors throughout the year. Now, bonito, a popular fish since the Edo period, has recently been given a new name, Mochigatsuo, which we have never heard of, and we would like to dig deeper into it.
The quality of bonito cannot be determined until it has been sliced.
As a general rule, one cannot identify a bonito just by looking at it, and even marketers and sushi chefs cannot tell its quality until they try to slice it. In particular, Hatsugatsuo (Noborigatsuo) has greater individual differences than Modori-gatsuo (Kudarigatsuo), and may even be inedible raw due to its distinctive odor. It is called Ishigatsuo or Gorigatsuo. Its flesh is noticeably firmer than normal fish in terms of elasticity. Its flesh is white, pink, or brownish. It also smells very bloody, almost like iron. The cause is currently unknown.
Because of its high hemoglobin and myoglobin content, bonito has a stronger bloody smell than other fish, even if it is not fresh. This richness is due to the high content of nitrogen compounds such as creatine and histidine, in addition to the umami substance inosinic acid. This is the reason for the unparalleled love of bonito.
The fishermen in the town of Susami, Wakayama Prefecture, immediately ikejime each bonito they catch on board, drain the blood out of the fish, and bring it back to the port in a container with its head in seawater ice.
On the other hand, bonito is a representative fish that loses its freshness quickly and is usually flash-frozen immediately after being caught. However, thanks to the tremendous efforts of fishermen, we can now eat fresh bonito. For example, fishermen in the town of Susami, Wakayama Prefecture, immediately ikejime each bonito they catch on board, drain the blood out of the fish, and bring it back to the port in a container with its head in seawater ice for the day’s auction. Kenkengatsuo is the result of thorough techniques for preserving freshness. The same is true of Taru-gatsuo from Hachijojima Island in Tokyo, for example. However, by the time the raw bonito arrives at the sushi restaurant to be made into Nigiri sushi, 12 hours have passed since the fish was caught. This time is critical to the quality of the fish.
So what kind of bonito is Mochi-gatsuo?
Hatsugatsuo has a refreshing, spring breeze-like flavor. Some of them are called “Mochigatsuo”, a type of bonito whose flesh is elastic and has the texture of freshly pounded rice cakes. Originally, bonito is caught far offshore, but in the spring, it comes much closer to land, so it can be brought to port before it becomes rigor mortis. Not all bonito are Mochi-gatsuo, however, and only a few are part of the same school, making them extremely rare. According to one theory, they are eaten before rigor mortis, which occurs four to five hours after the catch. Its season is from March to June, and it is consumed locally, as it is difficult to ship to distant places.
The name is also wonderful, as it compares the flesh of the bonito to a Mochi (rice cake). So far, the name “Mochigatsuo” is only used in Wakayama and Shizuoka regions. If you have a chance, you would like to try it.
