Hiroshima Oyster (Pacific Oyster, Cultivated)

The distinction is regulatory and reflects the harvesting sea-area's bacterial classification, not the freshness or quality of the individual oyster. Raw eating-grade (生食用) oysters are harvested only from sea areas designated as clean (typically deeper, offshore zones with strict bacterial monitoring) and are subject to rigorous post-harvest sanitation procedures (UV-sterilized seawater holding, etc.). Heat eating-grade (加熱用) oysters are harvested from inshore nutrient-rich zones (which produce larger, fatter, more flavorful oysters but have higher background bacterial counts that require thorough cooking before consumption). Counterintuitively, many oyster connoisseurs consider heat-grade oysters to have superior flavor when properly cooked — they are typically larger and more flavorful because the inshore feeding waters are richer. For OEM applications: raw-grade is required for raw-eating retail and oyster-bar foodservice (and commands a premium); heat-grade is preferred for kaki-furai, kaki-nabe, oyster-sauce production, smoked products, and any cooked or processed application. Mislabeling heat-grade as raw-grade is a serious regulatory violation.

Yes — oyster is the canonical natural zinc source globally. Raw oyster meat at 14.0 mg/100g zinc is the highest among common foods. A 100g serving provides approximately 130% of adult male daily reference intake (10 mg in Japan) and 175% of female RNI (8 mg). For supplement OEM, oyster extract (concentrated kaki-niku-extract — 牡蠣肉エキス) is an established Japanese ingredient category, with multiple Hiroshima-area producers supplying both food-grade and supplement-grade extracts. Functional positioning includes: zinc supplementation (taste/smell sensitivity, immune support), glycogen for fatigue recovery, and taurine (1130 mg/100g) for liver and cardiovascular support. For supplement OEM in Japan, nutrient content claims (亜鉛が豊富 / 'rich in zinc') follow standard nutrition labeling rules. Explicit health benefit claims (e.g., 'supports immune function') require Foods with Function Claims (FFC) registration. Some oyster extract products are marketed under the Kampo or natural-medicine framework and follow that regulatory pathway. Note that allergen disclosure (mollusc) and source-traceability documentation are essential for premium positioning.