The word oyster is used as a common name for a number of different families of saltwater clams, bivalve molluscs that live in marine or brackish habitats.
In some species the valves are highly calcified, and many are somewhat irregular in shape.
Many, but not all, oysters are in the superfamily Ostreoidea.
Some kinds of oysters are commonly consumed, cooked or raw, by humans as a delicacy.
True oysters are members of the family Ostreidae. This family includes the edible oysters, which mainly belong to the genera Ostrea, Crassostrea, Ostreola, and Saccostrea.
Oysters are an excellent source of zinc, iron, calcium, and selenium, as well as vitamin A and vitamin B12. Oysters are low in food energy; one dozen raw oysters contains 110 kilocalories (460 kJ). Traditionally, oysters are considered to be an aphrodisiac. A team of American and Italian researchers analyzed bivalves and found they were rich in amino acids that trigger increased levels of sex hormones. Their high zinc content aids the production of testosterone.
Unlike most shellfish, oysters can have a fairly long shelf life of up to four weeks. However, their taste becomes less pleasant as they age. Oysters should be refrigerated out of water, not frozen, and in 100% humidity. Oysters stored in water under refrigeration will open, consume available oxygen, and die.
Oysters must be eaten alive, or cooked alive. Oysters can be eaten on the half shell, raw, smoked, boiled, baked, fried, roasted, stewed, canned, pickled, steamed, or broiled, or used in a variety of drinks. Eating can be as simple as opening the shell and eating the contents, including juice. Purists insist on eating them raw, but it is common to add lemon juice, black pepper, or a splash of Tobasco. Like fine wine, raw oysters have complex flavors that vary greatly among varieties and regions: salty, briny, buttery, metallic, or even fruity. The texture is soft and fleshy, but crisp on the palate.
More information about Oysters in Knysna will provided at the event.