Echinoids is an alternative term for sea urchins, the spiny, globular echinoderms of the class Echinoidea harvested for their edible gonads, known as uni in Japanese cuisine. The gonads are prized for a sweet, briny, creamy flavour that commands premium prices, with quality graded by colour, firmness, and sweetness. Harvesting, opening, and packing demand speed and cold-chain discipline because the delicate gonads deteriorate rapidly at ambient temperature. Food safety concerns include bacterial contamination during hand processing and accumulation of marine biotoxins or heavy metals from the harvest area, so sourcing from monitored waters and sanitary handling are essential controls.