Exactly how does this work? Read on...
Ceviche-type dishes originated in the northern part of South America and have been a part of the cuisine from that region for centuries. Also called "cebiche" or "seviche," only recently has this style of preparation started gaining in popularity in the US.
To make ceviche, cubes or very thin slices of raw fish are marinated in citrus juice. The citrus interacts with the proteins in the fish, causing it to become opaque and firm. This gives the fish the appearance and texture of being cooked, though the actual texture is much more delicate than if the fish had been cooked with heat.
The citrus is traditionally lemon or lime, but any kind of citrus or acidic juice can be used. Lean white fish is also typical, though we've seen recipes with scallops, salmon, and even shrimp. It can be served unadorned with a fork or spoon, or you can scoop it into tortillas for a kind of fish taco.
A brief 15 minute dunk in citrus juice will affect just the surface of the fish, giving you a 'rare' preparation. For the citrus to work its way fully into the fish, it will need to marinate for upwards of an hour or more depending on the thickness of the fish.
A note on food safety: since the fish is never heated, be sure to buy the freshest seafood from a dependable source when you make ceviche at home.
Ceviche recipes from around the web:
What's your take on ceviche?