Below is an overview of expected storage times for different products at typical cold store temperatures.

Quality deterioration of products during cold storage is the main cause of FLW. If quality deterioration is severe, then products maybe discarded, which constitutes a food waste.  

Temperature change, biochemical changes, and dehydration during cold storage are the main causes of quality deterioration. Temperature fluctuations during storage will cause frozen products to melt or thaw slightly and then refreeze. This leads to the formation of large ice crystals inside the fish, which can cause physical damage to fish muscle.  

Fish proteins become permanently changed during freezing and cold storage and the speed at which denaturation, or breakdown of protein, occurs depends largely upon temperature. Ensuring that cold storage is at as low a temperature as possible/practical slows the rate of quality deterioration due to protein denaturation. 

Fatty fish may become unpleasantly altered during cold storage due to oxidation of fats, but they can be protected to some extent either by glazing or by packaging in plastic bags sealed under vacuum. These oxidation changes take place more rapidly at higher temperatures and when the product is exposed to air. Storage at a low temperature is an effective means of slowing the rate of spoilage. 

The quality of fish is often judged by appearance, and color changes which are not otherwise significant can result in fish being downgraded. The changes in the fish flesh which bring about these color changes are also retarded at lower cold store temperatures.

Dehydration is a major concern. When fish get badly dehydrated in cold storage, the surface becomes dry, opaque and spongy. Visible effects of severe dehydration on the surface of the fish are known by the term "freezer burn" which usually only appears after periods of cold storage.

Frozen fish may dry slowly in cold storage even under good operating conditions. This is undesirable for reasons other than the obvious one that the product will lose weight. Drying also accelerates denaturation of the protein and oxidation of the fat in the fish. Even totally impervious wrappers used to protect the product do not give full protection if the cold store operating conditions are favorable for desiccation within the pack.

In-pack desiccation prevails when there is some free space within the wrapper/packaging and the temperature of the store fluctuates. When this occurs, there will be times when the wrapper/packaging is colder than the fish and moisture will then leave the product and appear as frost on the inner surface of the wrapper/packaging. The total weight of the product and package will not change but if the in-pack dehydration is severe, the fish will have the quality defects of excessive drying.