Caviar is a luxury food made from the eggs of sturgeon fish. These eggs are typically harvested from wild fish, but farmed sturgeon are becoming increasingly common as a source for caviar. The eggs are processed and then either canned or jarred, and often pasteurized.
Pasteurization is a process of heating the caviar to a high temperature for a short period of time in order to kill any bacteria that may be present. This helps to prolong the shelf life of the caviar and make it safer to eat. However, some purists believe that pasteurization alters the flavor and texture of the caviar, so it is sometimes left unpasteurized. If you are unsure whether your caviar has been pasteurized, you can check the label or ask your provider.