This sheen is usually caused by bacterial decay, but not always. The chemical additive tripolyphosphate (nickname "tripoly" in the trade) is sometimes the culprit, especially when it's used excessively by overzealous fishermen and seafood processors. The method is simple: The seafood is soaked for several hours in a tripoly solution. The resulting chemical reaction retards the water loss that occurs naturally in protein tissue when a life form dies. Protein tissue loses water during the postdeath stage because its molecular structure contracts, decreasing its water retention ability. Tripoly raises the tissue's PH factor, causing the protein's molecular structure to unfold, thereby increasing its ability to bind water.

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