What is crab substitute made of? A survey of imitation-crab packages revealed that the first two ingredients are always fish (usually pollock) and water. After that come various processed starches (wheat and/or corn and/or potato), sweeteners (sugar and/or sorbitol) and sometimes egg whites. Finally, the packages state, the product "contains 2 percent or less of the following" and here's where you find salt, preservatives, colorants and other additives. Sometimes there are bits of actual crab or lobster, too.

In Japan, where such products originated, they are known as nerimono, or fish cake. According to Hiroko Shimbo's "The Japanese Kitchen" (Harvard Common Press, $16.95), nerimono production dates back at least 600 years. Its initial advantage was that it "makes it easy to eat fish that have many hairlike bones, which, along with the flesh, are pounded into a paste." The paste is known as surimi.

Today, the Japanese eat a lot of nerimono, but its many forms do not usually try to resemble "real" seafood.

For kamaboko, the fish paste is formed into a pure-white log with a pink-tinted exterior. You've probably seen slices of kamaboko on sushi platters and in Japanese soups.

Pacific Seafood, a leading American producer of surimi products, describes the manufacture thusly: "Surimi is made by pressing boneless fillets through an extruder, which produces a paste. The paste is then washed, a cryoprotectant is added (usually sorbitol) and the surimi is frozen in 22-pound blocks.

To make a seafood analog such as crab, surimi blocks are chopped and additional ingredients, including water, sugar, salt, binders, starches and flavors are added. The blended paste can then be extruded into a variety of shapes and steam cooked. Small amounts of real shellfish meat are added to premium seafood analogs, although, for all practical purposes, it is impossible to detect their presence in the final product."

By the way, in 2006, the FDA ruled that the product in question need no longer be labeled "imitation crab." The new label: "crab-flavored seafood, made with surimi, a fully cooked fish protein."

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