Sushi, as a distinctive and historical product of Japanese cuisine, is a type of dish that has become widespread around the world. Featuring both traditional and modern variations, sushi typically consists of key ingredients such as raw or lightly cooked fish, seafood, rice, and seaweed (nori).

^{A Sushi Plate (Pexels)}

History and Cultural Context

The origins of sushi lie in the combination of fish and rice through various techniques developed in Japan. Over time, different types of sushi—such as nigiri, maki, and temaki—emerged, along with distinct regional variations. For example, in the Nagano region, in addition to unique soba varieties like Togakushi, Takatō, Tomikura, and Tōji soba, regional sushi practices also draw attention.

Sushi has secured a strong place in both local and global cuisines, becoming a tangible example of core concepts in gastronomy such as competition, experience, and pride.

Nutritional Value and Health Benefits

The main ingredients of sushi, fish and seafood, are especially rich in omega-3 fatty acids (eicosapentaenoic acid and docosahexaenoic acid), which have beneficial effects on cardiovascular health. Additionally, wasabi consumed with sushi contains antibacterial compounds and supports the immune system. Seaweed (nori), while low in calories, is rich in various minerals and vitamins and may also aid in the elimination of heavy metals from the body.

Health Risks: Mercury and Heavy Metal Accumulation

Among fish species, the accumulation of heavy metals such as mercury—particularly in large predatory fish—is a significant concern monitored by international health authorities. Methylmercury enters aquatic environments through sources of environmental pollution (industrial emissions, fossil fuel usage, etc.) and can reach high levels through the food chain. Exposure to mercury increases the risk of neurological developmental problems, especially for pregnant women, children, and individuals with weakened immune systems. Therefore, many countries issue warnings advising pregnant women and sensitive groups to avoid fish species with high mercury content.

International regulatory bodies conduct monitoring of mercury levels in fish and promote public awareness. However, differences in regulations and enforcement highlight the need for increased consumer education and stronger inspections.

^{Sushi (California Roll) (Pexels)}

Health Risks: Biological Contaminants and Parasites

Consumption of raw or lightly cooked seafood carries potential risks related to parasites and microorganisms. Parasite species such as trematodes (flukes), nematodes (roundworms), and cestodes (tapeworms) can infect humans when preparation or hygiene conditions are inadequate. Parasitic infections can cause serious health issues, especially in individuals with weakened immune systems.

Microorganisms—including bacteria, viruses, and fungi—typically arise from insufficient hygiene, cross-contamination, or improper storage conditions. Spore-forming bacteria like Bacillus cereus can cause food poisoning related to rice, while viral agents such as Norwalk virus and Hepatitis A virus can be transmitted through human contact.

To reduce the risk of parasites in raw fish consumption, many countries have mandated deep-freezing procedures. However, this process has been reported to negatively affect the structural and organoleptic properties of the fish.

International Regulatory Policies and Inspections

International organizations such as the World Health Organization (WHO) and the Food and Agriculture Organization (FAO) establish standards aimed at enhancing food safety in seafood consumption and encourage countries to adopt compliant practices. Many nations inspect hygiene standards of establishments selling sushi and raw seafood, implement risk analyses and Hazard Analysis and Critical Control Points (HACCP) systems, and issue consumer warnings.

However, differences exist between countries in practice; some regions with high consumption levels lack comprehensive regulatory mechanisms. Local authorities, such as those in California, have introduced mandatory information disclosures at points of sale regarding mercury and other risks to protect consumers. There is growing demand for similar measures to be adopted more widely in other countries.