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Food Loss and Waste in Fish Value Chains
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Application of Appropriate Technology for Processing Plants

Technology is associated with the utilization of fish waste. Examples of how technology is used can be seen in the following.

Fish Processing Wastes as a Potential Source of Proteins, Amino Acids and Oils

About 70% of fish is processed before final sale. Processing of fish involves stunning, grading, slime removal, de-heading, washing, scaling, gutting, cutting of fins, meat bone separation and steaks and fillets. During these steps significant amount of waste (20-80% depending upon the level of processing and type of fish) is generated which can be utilized as fish silage, fish-meal and fish sauce. Fish waste can also be used for production of various value added products such as proteins, oil, amino acids, minerals, enzymes, bio-active peptides, collagen and gelatin.

Fish Waste Production in the United Kingdom

During processing, much is done to maximize the yield of edible products from fish, but thereafter, materials are discarded as waste or as a low value by-product. The fish-meal route is currently the most common use of fish waste, however, this option isn't practicable for all regions of the UK or for all waste material. Other uses for waste are currently being exploited but only on a very small scale. The revenue earned from selling fish waste is extremely low. However, this is preferable to paying landfill charges that are a harsh reality for many processors in some regions of the UK. Given current high prices for fish and increasing costs in all areas, the industry cannot afford to waste any opportunity to earn extra revenue. Fish waste is rich in potentially valuable oils, minerals, enzymes, pigments and flavours that have many alternative uses in food, pharmaceutical, agricultural, aquacultural and industrial applications. In addition to fish-meal and oil production, there is potential in silage production, fertilizer, composting, fish protein hydrolysate and fish protein concentrate. Non-nutritional uses include chitin and chitosan, carotenoid pigments, enzyme extraction, leather, glue, pharmaceuticals, cosmetics, fine chemicals, collagen, gelatin and pearl essence. There are countless other uses for this material and new uses are emerging all the time.

Co-products in the Swedish Seafood Processing Industry

A Swedish study found another way of increasing the value of processing co-products is to make the extraction of muscle from the rest raw material more cost effective. Many processors interviewed for the study stated that it was possible to cut out relatively large amounts of meat from backbones of salmon by hand, but that it was not performed in large extent since it was too time consuming. By using machines to separate remaining muscle from bones and skin the process can be made faster and at lower cost. There are machines available that can mechanically separate bone and meat today by pressing the raw material through a perforated rotating drum. Other, more novel ways of isolating muscle from bones and skin are by acidic/alkaline solubilization processes or by enzymatic hydrolysis, the latter generating peptides with other functionalities as compared to the intact proteins. These techniques open possibilities for production of foods for human consumption using rest raw materials. For example, the mince produced by the techniques mentioned can be added to fish products or used to produce surimi. Additional advantages of separating muscle via acid/alkaline solubilization or hydrolysis is that such fractionation could facilitate the extraction of valuable compounds. Compounds derived from seafood co-products used in cosmetics or for industrial and pharmaceutical appliances can generate high prices. A pharmaceutical product produced from seafood co-products, for example, is a cold-preventing mouth spray using the enzyme trypsin extracted from cod co-products. Additional uses, although of lower value than the ones mentioned above, is to use guts to produce silage which can provide pets and aquaculture fish with nitrogen.

Key Publications

Fish Processing Wastes as a Potential Source of Proteins, Amino Acids and Oils: A Critical Review

A review of waste from the seafood processing sector and options for its utilization.                                                                                                                                                                                                  

Fish Waste Production in the United Kingdom: The Quantities Produced and Opportunities for Better Utilization

The report estimates the types and quantities of fish waste generated in the different sectors, from catching to processing, and summarizes the current utilization or disposal of that waste.

Freshwater Fish Processing And Equipment In Small Plants

This document reviews the equipment used in freshwater fish processing, taking into account the different processing methods such as chilling, preserving, smoking and fish silage production.

 

More Resources

More Resources

This publication aims to provide technical guidance on the production and utilization of fish silage. This is intended for individuals and communities involved in fish processing, feed manufacturers and farmers.
Overview of fish waste, product options with focus on fish silage.
Experts in fisheries/aqua-feeds estimate that a quarter of fisheries wastes are discarded, causing a significant environmental impact and loss of potential product value. It is important to find adequate modalities to manage fish waste.