Oyster sauce is prepared from oysters, brine, umami flavour enhancers such as , and typically contains preservatives to increase its shelf life. The sauce was invented in 1888 by Mr. Lee Kam Sheung, in Nam Shui Village in Guangdong Province, China. His company, Lee Kum Kee, continues to produce oyster sauce to this day, along with a wide variety of Asian condiments.
A "true" oyster sauce of good quality should be made by condensing oyster extracts, the white broth produced by boiling oysters in water. This opaque broth is then d until a desired viscosity has been reached and the liquid has caramelized to a brown colour. The taste of MSG and non-MSG variants is similar.
Oyster sauce is used to enhance the flavour of many savory foods. It is also often used as a topping for steamed vegetables, and in .
Dishes for which oyster sauce is commonly used include:
* Bamboo steamed broccoli
* Steamed cabbage with
* Bao yu
* Beef with broccoli and mushrooms
In 2001 the United Kingdom Food Standards Agency found in tests of various oyster sauces and soy sauces that some 22% of samples contained a chemical called 3-MCPD at levels considerably higher than those deemed safe by the European Union. About two-thirds of these samples also contained a second chemical called 1,3-DCP which experts advise should not be present at any levels in food. Both chemicals have the potential to cause cancer and the Agency recommended that the affected products be withdrawn from shelves and avoided.