Month: October 2025

In Japan’s past, sushi was primarily known for its light and refreshing taste. Edo-period nigiri sushi centered on toppings like white-fleshed fish (such as hirame) or hikarimono (such as kohada) cured with vinegar or salt, where “freshness” and “clean, light flavors” were prized. Fatty fish spoiled easily and were not particularly favored among Edo diners.

However, as time progressed, food values underwent a significant shift. Advances in refrigeration and freezing technology made it possible to handle fatty fish while keeping them fresh, propelling toro, yellowtail, and salmon to become the stars of sushi. Toro, in particular, was once considered a “discarded part,” but is now celebrated worldwide as the “ultimate flavor.” To modern palates, fatty fish have a “melting richness” reminiscent of marbled beef, and this sensation fuels the popularity of fatty fish.

In recent years, fish such as blackthroat seaperch (nodoguro), splendid alfonsino (kinmedai), broadbanded thornyhead (kichiji), largehead hairtail (tachiuo), bigeyed greeneye (mehikari), and gnomefish (kuromutsu)—once rarely eaten by the public—have gained prominence as premium sushi toppings. These fish are often rich in fat and possess a deep umami flavor, embodying the “richness” and melt-in-the-mouth umami sought by modern palates.

Using fatty fish in sushi demands advanced craftsmanship. For fish like kinmedai and nodoguro, which have beautiful skin, special techniques are needed to highlight the skin’s beauty and the aromatic richness of the fat. Furthermore, to accentuate the natural sweetness in the fat, the temperature and acidity of the shari (vinegared rice), as well as the type of vinegar blend used, are subtly adjusted to balance the umami of the fat with the overall dish.

Through this accumulation of techniques, sushi chefs have refined their skill in “utilizing fat as umami.” Consequently, fatty fish have become not merely “rich ingredients,” but a canvas for the chef’s artistry and skill. Furthermore, modern taste preferences are underpinned by shifts in Japanese dietary habits. Increased consumption of fatty foods like meat and butter, coupled with palates accustomed to processed foods and chemical seasonings, now responds more strongly to rich, fatty, or salty flavors than to subtler tastes. This environment also fuels the growing preference for fatty fish.

Moreover, the influence of media and social networks heightens expectations of deliciousness even before tasting.

Thus, the fatty fish once shunned by Edo-period people now captivates as a “fish representing sushi.” This shift in taste can be seen as a uniquely modern symbol of affluence, born from technological progress and cultural sophistication.

― From the Science of Taste, Culinary Techniques, and Cultural Background ―

Why do soy sauce and wasabi alone complete the flavor of sushi? It is because the umami and aroma of the seafood, the acidity of the vinegared rice, the chef’s skill, and the values of Japan’s unique food culture all unite, come together harmoniously in the mouth.

The umami components in seafood, such as glutamic acid, inosinic acid, and succinic acid, combine with the acetic acid in the vinegared rice and the amino acids in the soy sauce to create a deep flavor. Soy sauce integrates these umami flavors, and its fermented aromatic components (phenols and furanones) blend with the natural aroma of the seafood to add depth to the flavor. Salt tightens the flavor profile by assisting taste receptors, balancing the overall composition alongside the vinegar rice’s acidity.

Furthermore, the pungent compound allyl isothiocyanate in wasabi is also perceived as an aroma in the nasal cavity, uniting spiciness and fragrance to further enhance the multidimensional taste experience.

The unsaturated fatty acids (EPA and DHA) contained in fish fat oxidize slightly to produce volatile components such as hexanal, which are perceived as the “aroma of the sea.” These aromas are released most naturally at room or body temperature. The acidity of the vinegared rice melts in the mouth and enhances the aroma, bringing out the maximum umami of the fish topping and creating a scientifically sound harmony of flavors.

The artisan’s skill exists to further enhance this chemical interaction. They perform preparatory steps tailored to the freshness and condition of each topping, removing excess moisture and off-odor to highlight the ingredient’s inherent umami. Cutting techniques are also meticulously chosen for each topping—such as sogigiri (angled slicing), hikkikiri (pulling cut), or hirazukuri (flat slicing)—considering the fish’s fiber and fat distribution to adjust texture and aroma release.

The temperature and firmness of the shari (vinegared rice) are precisely calculated to ensure the fish’s fat melts perfectly in the mouth, creating the moment where aroma and umami unite. Wasabi is meticulously adjusted in quantity and placement for each piece to accentuate its fragrance and balance the mouthfeel. The combination of all these elements creates a single, complete taste experience in the mouth.

And cultural background underpins this harmony. This refers to a culinary philosophy that highlights the inherent appeal of ingredients by subtracting unnecessary elements rather than adding excessive flavors or aromas. For example, instead of drenching fatty white fish in strong sauce, it is designed so that the fish’s natural umami and aroma can be felt in a single bite, simply seasoned with the spiciness of wasabi and the saltiness of soy sauce. Whereas Western cuisine is often described as “additive cooking,” building flavor through layers of seasonings and sauces, sushi emphasizes the natural flavors of ingredients through subtraction.

The umami of the fish, the flavor of its fat, the acidity of the rice, and the aroma of the wasabi are calculated to harmonize naturally. In the early Edo period, wasabi was expensive and not something commoners could use daily. However, during the late Edo period, as “hayazushi” (sushi using vinegared rice to shorten fermentation time) became popular at street stalls, artisans noticed that wasabi’s spiciness and aroma enhanced the flavor of raw fish. They gradually began incorporating it into sushi. Thus, artisans continued refining their craft to complete each piece with minimal adjustments while respecting the individuality of the ingredients, establishing the philosophy of harmonious flavors in sushi.

Thus, sushi is perfectly complete with just soy sauce and wasabi. The fusion of scientific umami synergy, the artisan’s meticulous technique, and the cultural backdrop of the subtractive aesthetic allows one to experience the depth of flavor and the three-dimensionality of aroma in a single bite. Soy sauce and wasabi are not mere seasonings; they embody the essence of sushi.

― Raw gastronomy supported by science and culture ―

Japanese sushi is recognized worldwide as “safe to eat raw.” In many countries, consuming raw fish carries risks. Bacteria, parasites, and inadequate temperature control can lead to food poisoning. However, a culture where sushi and sashimi can be enjoyed with confidence has been built over a long history in Japan. This is no accident; it is the result of scientific management and laws combined with artisans’ skills and cultural awareness. Let’s take a closer look.

Thorough freshness management via cold chain

When discussing the safety of Japanese sushi, the most crucial element is the low-temperature management system known as the “cold chain.” This refers to the mechanism that maintains a constant temperature throughout the entire process, from the fish being caught in the sea to its arrival at the sushi counter. First, the caught fish is immediately chilled with ice onboard the vessel and kept at a low temperature around 0°C. This minimizes bacterial growth and deterioration of freshness. Then, the fish is delivered by refrigerated trucks from the fishing port to the fish market.

Upon arrival at the fish market, the fish is kept at low temperatures in the auction halls and warehouses, maintaining its freshness until purchased by the chefs. Transportation from the market to the restaurants also uses dedicated refrigerated trucks or containers to maintain a constant temperature. At the restaurants, further management occurs in the sushi display cases and refrigerators, ensuring the quality of the fish remains at its absolute best.

Furthermore, fish like salmon, which carry a risk of parasites, undergo proper freezing during distribution, ensuring they are safe for raw consumption. This rigorous temperature control from catch to plate is what makes Japanese sushi a unique “safe raw food” unmatched anywhere else in the world.

Japan’s globally high food safety standards

One reason Japanese sushi is globally safe is its strict food safety standards based on laws and systems. Japan’s Food Sanitation Act thoroughly regulates the hygiene management of raw fish for consumption and cooking utensils. Furthermore, the HACCP (Hazard Analysis Critical Control Point) system is implemented in all food service establishments, analyzing hazards and clearly defining control points at each stage from fish reception and refrigerated storage to cooking and serving. For example, meticulous hygiene management is routinely practiced, covering details such as temperature control of sushi toppings, parasite risk management, maintaining hand cleanliness, and disinfecting knives and cutting boards.

Sushi restaurants also strictly adhere to these standards. Beyond simply complying with laws and regulations, hygiene awareness is thoroughly instilled during the training of their chefs. Maintaining hand cleanliness, disinfecting cooking utensils, and controlling the temperature of sushi toppings are daily routines across all sushi establishments.

Furthermore, regular on-site inspections are conducted by municipal health centers. These inspections verify temperature management records, kitchen cleanliness, and employee handwashing practices. Violations result in corrective guidance and, in some cases, suspension of operations. This combination of legal oversight and artisan traditions enables Japanese sushi restaurants to routinely achieve a level of hygiene management unparalleled anywhere else in the world.

According to the Tokyo Metropolitan Government Health and Medical Services Bureau, the number of food poisoning incidents in fiscal year 2025 was 114 cases (affecting 1,536 people). Compared to 76 cases (affecting 833 people) at general restaurants, sushi restaurants had only 8 cases (affecting 27 people), a very low number.

Sushi chefs’ rigorous sanitation practices

One of the most critical factors supporting the safety of Japanese sushi is the daily sanitation practices of sushi chefs. Chefs pay meticulous attention to sanitation, just as much as they do to their nigiri-making and knife skills.

Maintaining clean hands is the top priority. Chefs wash their hands between tasks and disinfect their fingertips with vinegar water. Cutting boards and knives are also wiped down and disinfected after each sushi. These practices prevent cross-contamination. Furthermore, during their apprenticeship, trainees are rigorously taught by their masters to visually inspect fish for anisakis parasites and remove them thoroughly.

Sushi toppings are always kept below 5°C (41°F) to minimize bacterial growth. Careful consideration is given to the chef’s workflow and tool placement. Areas for handling raw fish and cooked ingredients are separated, and dedicated tools are used to prevent cross-contamination.

Sushi chefs’ hygiene management is not merely a formality; it is a scientifically grounded “procedure for ensuring safety.” The chefs’ experience and skill are reflected in their daily hygiene practices, allowing us to enjoy raw sushi with confidence.

A culture that values freshness and eating food right away

One reason Japanese sushi is safe and delicious lies in its “freshness-first, eat-food-immediately culture.” This culinary tradition, passed down from the Edo period to the present day, is based on the premise of eating fish caught on the same day. At sushi restaurants, it is standard practice to prepare and serve fish purchased at the market that very day.

This culture maximizes the freshness of fish, rice, and seasonings while significantly reducing the risk of food poisoning.

Summary

It is the combination of tradition, science, the artisan’s skill, and a culture that values freshness that makes Japanese sushi so reliably safe to eat raw. The combination of a culture prioritizing freshness dating back to the Edo period, scientific temperature control and inspection, and artisans’ meticulous hygiene management achieves a level of safety unparalleled anywhere in the world.