Another possibility for the name could come from the traditional method of harvesting. 'Sashimi Grade' fish is caught by individual handline. As soon as the fish is landed, its brain is pierced with a sharp spike; and it is placed in slurried ice. This spiking is called the Ike jime process, and the instantaneous death means that the fish's flesh contains a minimal amount of lactic acid. This means that the fish will keep fresh on ice for about ten days, without turning white or otherwise degrading.[citation needed]Many non-Japanese use the terms sashimi and sushi interchangeably, but the two dishes are distinct and separate. Sushi refers to any dish made with vinegared rice. While raw fish is one traditional sushi ingredient, many sushi dishes contain seafood that has been cooked, and others have no seafood at all.