Shellfish and Crustacean Displays in Seafood Department Showcases
The color of seafood displays is important to eye appeal. Cooked crab, shrimp and lobster should appear bright red but under some retail fluorescent lighting they can appear brownish. Supermarket fluorescent lighting tends to be strong in the green and yellow areas of the visible spectrum, which distorts the natural color of crustaceans and shellfish, and makes ice beds look green or yellow.
Decomposition of Retail Seafood and Shellfish Displays
The heat and radiation emitted by seafood display case lighting can raise the temperature of lobster, shrimp, crab, and shellfish displays to unsafe levels. With prolonged exposure to heat and UV radiation from seafood merchandiser lighting, seafood decomposes and begins to smell fishy.
Even a slight rise in temperature above the ideal 29°F can cause bacteria to grow exponentially, and a two degree increase can make seafood dangerous. Pasteurized crab meat can still lead to food poisoning if it is temperature abused.
Seafood display cases that are cooled only by ice beds are particularly susceptible to the heating effects of display case lighting radiation and tend to experience large temperature variations. In these ice bed display cases, the ambient temperature two inches above the ice can reach room temperature.
When oysters, clams, and mussels are stored at temperatures that are too warm, the shellfish open their shells, and do not stay as fresh.
Light and oxygen trigger lipid oxidation, a chemical reaction that turns fats rancid.
Seafood Dehydration and Drip Loss in Retail Displays
Heat and ultraviolet radiation dehydrate seafood displays, causing crustaceans and shellfish to shrink and weigh less than they should, directly affecting the retailers’ profit since seafood is generally sold by weight.
Moisture evaporates when exposed to heat and radiation, but seafood also becomes dehydrated as part of the decomposition process, which causes cells to lose their ability to retain water, resulting in drip loss as water oozes out of oysters, shrimp, and shellfish.
The amount of drip loss varies from species to species and may be double for one species versus another. In three days, cooked shrimp can lose 15% of their weight, and raw shrimp loses even more.
Dehydration and water loss can kill shellfish, and affects the appearance and taste of other seafood.