The vessels range in size from 240 to 800 tons. Only a small portion of the fleet is refrigerated in Peru, in Chile more vessels are refrigerated. Most of the fish is caught within 2 to 4 hours from the plant, sometimes the landing is 6 to 8 hours from the fishmeal plant.
What Types of Fish are Used?
Fishmeal can be made from almost any type of fish but is generally manufactured from two main types. These two types of fish differ both in their ability to store oil as well as where in the body oil is stored.
The first type includes a group referred to as "LEAN FISH". This includes such species as Cod and Haddock. In these species the oil is stored primarily in the liver. The flesh (fillets) contain very little oil. Fishmeal from this type of fish has a low oil content (2 to 6%) since the livers are removed before processing. Of course, if the livers are added back, or the whole fish is used, the oil content would be higher. The whole fish is not usually used since Cod and Haddock are prized for the fillets. Since the fillets are used for human consumption, the fishmeal from these lean fish are made principally from the offal (white fish frames) remaining after filleting. "White" fishmeal commonly contains a higher concentration of ash (minerals) since the bony frames (head and racks) of previously filleted Cod, Haddocks, etc. are used. White fishmeal constitutes only 10% of the world fishmeal production.
The second type of fish used to manufacture fishmeal stores oil in certain parts of the flesh. They are high oil fish and, unlike the lean fish, are not prized for their fillets. They are commonly referred to as "INDUSTRIAL FISH." Such species as Herring, Menhaden, Anchovy, Pilchard, Sardines and Mackerel fall into this category. Approximately 90% of the world fishmeal production is from these high oil species.
Most species of fish used for the production of fishmeal have a similar
protein content that averages approximately 16% in the whole fish. This
whole body protein content will vary by only plus or minus 2 to 3%.The
oil (fat) content in fish species is much more variable than their protein
content. Raw fish could produce 23.1% fishmeal and 7.6% oil.
Freshness = Quality
The shorter the time from catch to plant ensures a fresh supply of fish which also helps to preserve the freshness and the quality of the raw material. The capacity of the plant also play a major role in fishmeal process, when the fish is processed in a shorter period of time, thereby not allowing the decomposition of the raw material to take place. Ice is added to the storage pits when the fish is discharging from the fishing vessel, this allows the plant to discharge rapidly when there is a large fish landing so that they could preserve the freshness before decompose takes place in the storage pit during process or in the fishing vessel if it is not refrigerated (again, this is common in Chile, Peruvian companies normally do not have this facility). 60 to 80 tons of raw fish per hour are the most commonly production capacity found in Peru, while in Chile 80 to 100 tons of raw fish per hour is commonly found. In Peruvian fishing zone the main species caught is Anchovy and Sardine, while Jack Mackerel is the main raw supply in Chile's Concepcion Bay area.
Anchovy (Anchoveta)(Engraulis Ringens Jenyns)
Anchovy fishing area : Chimbote, Huarmey, Supe, Huacho, Callao, Pisco, Ilo.
Sardine (Sardina)(Sardinops Sagax Sagax)
Sardine fishing area : Paita, Parachique, Santa Rosa, Chimbote.
Jack Mackerel (Jurel)(Trachurus Picturatus Murphyi Nichols)
Mackerel fishing area : Paita, Parachique, San Jose, Chimbote, Callao.
Every 4 to 4.5 MT of raw material can produce 1MT of fishmeal
Fishmeal is made by cooking, pressing, drying and grinding the fish.
The fish is first pump to the factory from off shore pumps, the ratio of fish and sea water is 1:2 some factories in Chile use 1:4. Higher sea water ratio will keep the fish in one whole piece, which is important for the canning industary and the fish do not decompose quickly.
The fish is passing through a Dewatering vibrator and a weight before entering the storage pit.
A better pumping system and fish water ratio.
The water collected from the dewatering vibrator is stored in another pit in order to extract the fish fats and smaller pieces of the fish.
During cooking, the fish move through a long, steam-jacketed, screw conveyor cylinder. Cooking coagulates the proteins and is a critical process responsible for sterilizing the product and preparing it for liquor (a mixture of oil, water and protein called "STICKWATER" or "AGUA COLA") removal. If the fish is over cooked or the temperature is too high the meal will have a lower digestibility. It takes 35 minutes at a temperature of 80 degree to cook the fish. The Cookers raw material capacity ranges from 30 to 50 tons per hour.
Cooker. Pressor. Presscake.
Once cooked, the liquor is removed by pressing. The solid residue that remains after pressing is called "PRESSCAKE". The liquor is centrifuged to remove the oil then transported to storage tanks. Prior to storage, it is essential to add an antioxidant. The antioxidant will stabilize the oil so that oxygen will not cause damage during storage. The stored oil must not come into contact with air, heat or light in order for its quality to be maintained.
Stick water evaporating system.Centrifugal recuperator.
Stickwater may contain as much as 20% soluble protein, solids, etc. and is valuable. The total content of the solids in stickwater(8~10%), proteins(5.6%), fat(0.6%), ash(1.8%), moisture(92%). As a general rule, about 60% of the fish weight will be generated as stickwater with about 8% total solids. Plants do not recover stickwater by evaporation the losses will be approximately 48 kg/ton of fish. The stickwater is evaporated (It is specially designed for evaporating stickwater in fishmeal and oil processing, the Evaporating system with a raw material capacity of 40 to 120 tons per hour.) to a thick syrup containing 30 to 50% solids. This material is called "CONDENSED FISH SOLUABLES" it will be added back to the presscake and dried with it. The meals are then dried so that the moisture content is low enough to allow the meal to be stored and transported without mold or bacterial growth.
Drying can be either direct or indirect. Direct drying is the most rapid and requires very hot air or flame (Flame Dried) to be passed over the meal as it is rapidly tumbled in a cylindrical drum. If this process is not carefully controlled the fishmeal may be scorched. The fishmeal produced in this method is "FAQ" fishmeal.
Dryer.Inside the Conveyor Feeding screw.
Indirect drying (Steam Hot Air) requires a steam-jacketed cylinder (called "ROTATUBE") or a cylinder containing steam-heated discs (called "ROTADISC") which tumble the meal. Residence time in the Rotatube dryers is only 20 minutes, while Rotadisc dryers require 2 hours or more. The critical parameter is that the maximum product temperature of the rotatube dryer is 20 C to 30 C lower than that of the rotadisc dryer, and the best way to produce highly digestible fishmeal is to dry the fishmeal at a very low temperature, in a short period of time. The dryer capacity ranges from 20 to 30 tons per hour. The fishmeal produced is called "STEAM DRIED". After drying the meal is then transport to a cylinder ("COOLER") to lower the temperature. The fishmeal cooler consists of an static cylinder that uses bladed rotor to move and mix the fish meal with air. The cooling air is forced in countercurrent into the system by using fan and the small particles are recovered by a cyclone before exhausting the air.
Once the fishmeal is dried it has to be ground and add antioxidant into the meal, packed in bags, palleting or stored in warehouse (either open space or roofed facilities) for bulk delivery.
Hammer Miller. Adding Antioxidant before packing.
Packing. Storage space is disinfected before putting the bags into stacks.
Chile fishmeal pallet and bulk warehouse