Fishmeal and fish oil are produced by a continuous and carefully controlled process which involves cooking, pressing, drying and milling of fresh, raw fish.
Yields of fishmeal and fish oil can vary between fish species and even from season to season, but typically around 17 22% fishmeal and 5 15% fish oil will
be obtained by processing. The following summary provides a step by step guide to
the production process.
- 1. Intake Raw fish is sampled and analysed on intake to check for freshness and expected yield of meal and oil.
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2. Cooking - The raw fish is conveyed through a steam heated continuous
cooker, where it is heated to 90°C-95°C. This sterilizes the fish,
coagulates the proteins and disrupts the cell membranes to facilitate
the separation of the solubles and the oil from the dry matter.
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3. Press - The cooked raw material is fed to a screw press where much
of the liquid is squeezed out to form a presscake which is conveyed to
the drier.
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4. Separator The press liquid contains water and most of the oil from
the fish, as well as dissolved proteins, salts and fine particles.
These particles, sometimes called sludge, are removed in a decanter and
transported to the drier to be mixed in with the presscake. The liquid
from the decanter is fed to separators where the oil is removed and can
subsequently be stored in large tanks for export.
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5. Evaporator - The water phase from the separators is fed to the
evaporators where it is gently concentrated before being blended with
the presscake during the drying stage.
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6. Drier - The water in the press cake, sludge and concentrate is
removed by rapid air drying after which the fishmeal is cooled, milled
and stored for export.
This method of processing is necessary to obtain marketable products which can be easily stored, transported and utilized.
Click here for a diagram showing the production process
Click here for a diagram showing the drying process
International Fishmeal and Fish Oil Organisation
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