Shrinkage of Fish and Seafood in Supermarket Seafood Departments
Seafood departments deal with the greatest health risk, the greatest product shrinkage, and the shortest product shelf life of all supermarket departments. The shelf life of seafood depends in large part upon the storage and transport conditions during the time the seafood was caught and the time it is put on display, which can be as long as a week.
In a meat or deli department, product that does not sell can be re-wrapped or converted to another product, but if fish or seafood does not sell when it is fresh, it must be discarded. As a result, fish worth $20 per pound can become a significant loss if it becomes dehydrated or is not sold before it spoils.
Measuring Shrinkage Loss in Retail Seafood Departments
Loss due to shrinkage can be calculated in two ways. When seafood retailers buy and sell seafood by weight, shrinkage is the loss in weight due to dehydration from the time the seafood is bought to the time it is sold.
Alternatively, shrinkage is the revenue lost from marking down prices on seafood that no longer looks perfect and has not sold, discarding spoiled and rancid seafood, wasteful preparation such as creating fillets with less flesh than they could have, dehydration, and theft.
Radiation from lighting sources heats the surface of seafood displays and evaporates moisture. Promolux lamps and LEDs emit lower levels of damaging visible spectrum and UV radiation, preventing dehydration and prolonging the shelf life of seafood displays.
Shrinkage Rates of Grocery Store Seafood Displays
Shrinkage rates at retail seafood outlets surveyed by the Food Marketing Institute varied depending upon the size of the seafood display and whether the seafood display counter was full service or self-service.
Large full service seafood counters had shrinkage rates of 15%, while small full service seafood counters had shrinkage rates of just 5%. The opposite was true for self-service counters: retail stores with large self-service seafood counters had lower shrinkage rates than retail stores with small self-service seafood counters. If unrefrigerated ice bed display cases are used, the loss can be even higher.
This reflects the fact that large full service counters require a great deal of maintenance, because they contain unpackaged seafood and fish that are more sensitive to the harmful effects of light and oxygen.
Seafood Dehydration and Drip Loss in Refrigerated Cabinets
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, shellfish, fin fish, fish steaks and fish fillets.
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.
Retail display lamps that encourage the growth of bacteria accelerate the decomposition process. Under Promolux Safe Spectrum lighting, seafood displays last up to 50% longer.
Lipid Oxidation of Seafood and Fish Fats in Supermarket Merchandisers
When exposed to light and oxygen, fats in fish and seafood become oxidized and turn rancid, notable as a strong fishy odor. This process is triggered by radiation from the visible and ultraviolet spectrums, and is not dependent on temperature since this radiation can penetrate refrigerated and sub-freezing atmospheres.
Promolux lamps and LEDs minimize the damaging effects of retail display lighting because they 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 heat and damage surfaces.