Hiroshima Oyster (Pacific Oyster, Cultivated)

Hiroshima oyster is cultivated Pacific oyster (Crassostrea gigas, magaki / 真牡蠣 in Japanese), grown using the Hiroshima-style hanging cultivation method in Hiroshima Bay's nutrient-rich Seto Inland Sea waters. Cultivation cycle is 2-3 years from spat (seed oyster) to harvest. Harvest season runs October through April; the regulatory 'R-bearing months' rule (months containing the letter R, i.e. September through April) applies to peak quality positioning.

Nutritionally, raw oyster meat is exceptional: 6.9g protein, 2.2g fat, 4.9g carbohydrates (notably high glycogen storage), and the standout micronutrients zinc 14.0 mg/100g (the highest of any common food), iron 2.1 mg/100g, copper 1.04 mg/100g, vitamin B12 28.1 μg/100g, and taurine 1130 mg/100g. The zinc content makes oyster the canonical natural zinc source — 100g delivers approximately 130% of the adult male daily reference intake (10 mg) and 175% of female RNI (8 mg).

Industrial production: Hiroshima accounts for approximately 60% of Japan's cultivated oyster volume; Miyagi (Sanriku) is the second major region. Premium Hiroshima brands include Hiroshima Bay-area-specific producers (Etajima, Otake, Kure). 'Raw eating-grade' (生食用) commands a premium over 'heat eating-grade' (加熱用) and is restricted to oysters from designated clean sea-area zones with strict bacterial monitoring.

Premium retail and foodservice — fresh oysters (in-shell or shucked) for raw consumption (kaki-zushi, raw oyster bar) and for cooking (kaki-furai breaded fried oyster, kaki-nabe oyster hot pot, kaki-meshi oyster rice). Winter is the peak retail season.

Zinc-functional positioning — oyster meat retail and foodservice are positioned around the natural zinc, glycogen, and taurine content for fatigue recovery, immune support, and reproductive health functional positioning (note that explicit health claims require regulatory registration).

Oyster sauce ingredient supply — the boiled-down oyster extract is the foundational ingredient for oyster sauce, a major Asian condiment. Industrial oyster extract production (typically Hiroshima-Miyagi region) is the upstream input for oyster sauce manufacturers.

Functional ingredient extracts — oyster extract (concentrated oyster meat extract, marketed for zinc, taurine, and glycogen content) and oyster glycogen extract are used in functional food and supplement applications. 'Kaki-niku-extract' (牡蠣肉エキス) is an established category in the Japanese functional food industry.

Premium gift retail — high-grade Hiroshima oysters in cooled gift retail packs are an established winter seasonal gift category. Smoked-oyster canned products (Hiroshima brands) are also a long-established gift category.

For OEM: live oyster cold-chain supply (foodservice), shucked raw and heat-grade oyster meat (retail and processed-food use), frozen IQF oyster meat (foodservice and processed-food ingredient), oyster extract and oyster glycogen (functional ingredient supply), oyster sauce production input (industrial commodity), smoked-oyster canned gift retail, and ready-to-cook kaki-furai and kaki-nabe meal-kit components.

Food Sanitation Act standards. 'Raw eating-grade' (生食用) vs 'heat eating-grade' (加熱用) labeling is mandatory based on harvesting sea-area bacterial classification.

Norovirus management: oyster industry maintains active norovirus monitoring; recall protocols are well-established.

Origin region claims (Hiroshima, Etajima, Miyagi) require verifiable cultivation-area documentation.

Allergens: oyster is a Specified Allergen under JAS recommended labeling. Disclosure required.

Functional claims for zinc, taurine, glycogen content require Foods with Function Claims (FFC) or Foods for Specified Health Use (FOSHU) registration. General nutrient content claims (亜鉛が豊富 / 'rich in zinc') follow standard nutrition labeling rules.