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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 crabmeat can still lead to food poisoning if it is temperature abused.

Seafood display cases that are cooled only by icebeds are particularly susceptible to the heating effects of display case lighting radiation and tend to experience large temperature variations. In these icebed 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.

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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.

For seafood science references and excerpts click here.

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Promolux True Color Definition Lamps

Compared to other fluorescent lighting, Promolux Safe Spectrum lamps emit 86% lower UV B radiation, a shorter wavelength that penetrates and causes heating, and 52% lower UV A radiation, a longer wavelength that tends to affect surfaces. Because Promolux lamps are designed for true color definition, they have a more balanced visible spectrum than other fluorescent lamps.

Yellow and green wavelengths are the most damaging wavelengths in the visible spectrum, and their predominance in regular fluorescent lighting can distort the natural colors of seafood and make ice beds look green or yellow. Promolux lamps emit a more balanced range of wavelengths, including more of the red and blue wavelengths and more moderate levels of the yellow and green wavelengths. It is impossible to create a natural light that does not have any yellow or green wavelengths, so light sources will always be damaging to some extent.

However, since Promolux Safe Spectrum lamps minimize the emission of damaging visible spectrum and UV wavelengths, using Promolux lamps will prolong the shelf life of shellfish and crustaceans and maximize their fresh appearance, enticing customers to buy while the seafood is fresh.