Fish Mince Production: Manual and Mechanical Methods

Fish mince is one of the most versatile raw materials in the seafood processing industry. It forms the base for everything from fish balls and fish cakes to surimi-based imitation seafood. But before any of that can happen, the meat has to be cleanly and efficiently separated from the bones. That separation – the production of fish mince itself – can happen in one of two ways: manually, through skilled hand labour, or mechanically, using specialized deboning equipment. Each method has its own logic, its own strengths, and its own appropriate context.

What is fish mince and why does production method matter? 🔗

Fish mince is a paste-like product made from fish flesh that has been separated from bones, skin, and connective tissue. According to ScienceDirect, one of the major advantages of minced fish is the level of control it gives processors over product flavouring, texture, appearance, and storage properties – qualities that are harder to achieve with whole fillets. Since the mincing process removes species recognition visually, the World Food Logistics Organization notes that nearly any edible fish species can be used alone or in combination to create the desired product. This makes the choice of production method – manual or mechanical – a critical decision that directly affects yield, quality, and profitability.

Pre-production preparation: getting the fish ready 🔗

Whether you are using manual or mechanical methods, fish preparation before mince production follows a common sequence. The fish must first be beheaded and gutted. This is not just a housekeeping step – it’s a food safety essential. The FAO’s freshwater fish processing guide notes that removing the head eliminates potential contamination sources including gills and brain tissue, both of which can harbour bacteria that compromise the quality of the final product. Visceral contents, if left intact, can release harmful enzymes and break down the flesh from within.

The header/gutter machine is designed to remove the head, viscera, and a major portion of the backbone in a single pass. Alternatively, a manual technique called knobbing – cutting off the head and pulling out the gut in one motion – is used where mechanical equipment is unavailable. The FAO’s Fish Value Chain resource confirms that gutting is among the most basic processing steps designed to extend shelf life and prevent microbial contamination. For larger fish, size reduction using a crusher may also be required before deboning begins.

Manual method of fish mince production 🔗

The manual method is the older of the two approaches and remains widely practiced in small-scale fisheries, particularly in regions where mechanization is limited or economically unfeasible. It involves skilled workers using knives and hand tools to fillet the fish and then separate the remaining meat from the frame.

Filleting as the first step 🔗

Filleting is the process of cutting the flesh away from the backbone and rib cage to yield boneless slabs of meat. As described by Take Me Fishing, the standard approach involves laying the fish on its side, cutting behind the gills down to the rib cage, then running the knife along the backbone from head to tail to detach the fillet. The rib section is then trimmed away, and the skin removed by angling the blade between the flesh and skin while holding the tail end firm.

One detail that distinguishes high-quality manual filleting from a basic cut is the removal of pin bones. The Kitchn’s guide on fish filleting explains that pin bones run along the center of the fillet and must be pulled out individually with fish tweezers or pliers, as they are too fine and numerous to cut around. For freshwater species like carp, academic courseware from IGNOU’s eGyanKosh portal notes that fillets typically contain 5-7% pin bones, and a special ‘V’ cut is used to produce a fully boneless fillet of very high quality.

Manual meat picking from frames 🔗

After filleting, the fish frame – the skeleton with residual meat – still holds a meaningful amount of usable flesh. In manual mince production, workers pick this remaining meat by hand or with tools. ScienceDirect’s overview on minced fish points out that most fish processing operations discard a significant amount of edible flesh in the form of pieces removed from fillets or meat left on the frame. Manual recovery of this residual meat is possible but slow, and the yield is lower compared to what a machine can extract.

The FAO guide on freshwater fish processing further notes that manual filleting and deboning are time- and labour-consuming procedures, and that even with skilled workers, the level of mechanization in small plants remains low due to limited production volumes and seasonal availability of raw material. This makes manual methods more suitable for small batches, higher-value species, or settings where investment in equipment is not justified.

Mechanical method of fish mince production 🔗

Mechanical fish mince production uses specialized deboning machines to automate and scale up the separation of flesh from bone. These machines can process far larger volumes far faster than hand labour, and they are capable of extracting mince from fish that would be impractical to fillet manually – particularly small-bodied, bony, or low-value species.

How the deboning machine works 🔗

The core technology in mechanical mince production is the belt-and-drum type deboner. According to the IGNOU fish mince production unit, in a mechanical deboner, the fish flesh is forced by means of a rubber conveyor belt through a perforated drum. The skins and bones remain on the outside of the drum, while the fish mince is collected from the inside. A peer-reviewed study published in the Journal of Food Science and Technology confirms this design: the machine consists of a perforated drum, a single-phase electric motor, a speed-reduction gearbox, and a belt drive system, and was evaluated using Tilapia with a processing capacity ranging from approximately 45 to 78 kg per hour, depending on belt type and drum speed.

Commercial fish deboning equipment operates on a pressure-squeezing principle – the rubber belt and perforated drum work together so that soft fish flesh is forced through the holes while bones, skin, and fins are left behind. The pressure between the rubber belt and the extracting tank can be adjusted according to fish size, which means the same machine can handle multiple species.

Perforation size and its impact on quality 🔗

One of the key technical variables in mechanical deboning is the size of the holes in the drum. Research from the Journal of Food Science and Technology used a 3 mm perforation diameter in testing. Industry documentation on deboning machinery explains that smaller perforations produce finer mince with fewer bone fragments but reduce overall yield, while larger holes increase yield but risk allowing small bone fragments through. Typically, hole diameters range from 2 to 5 mm depending on the fish species being processed, and processors must find the right balance for each application.

Drum-type vs. belt-type deboners 🔗

There are two main configurations of mechanical deboners. Belt-type deboners use a continuous belt system that carries fish portions against a perforated drum or plate. The belt moves under increasing pressure, forcing the soft flesh through while carrying away waste material. This continuous-feed design makes it well-suited for high-volume production lines. Drum-type deboners, by contrast, use a rotating perforated drum that generates centrifugal force to push flesh through the perforations. The rotation speed directly impacts the tradeoff between throughput and separation quality – higher speeds process more fish but may compromise mince purity, while lower speeds produce cleaner mince at reduced capacity. Modern drum deboners offer variable speed control to optimize this balance.

Commercially employed machines for the mincing operation include models like the Baader 605, Baader 607, and Baader 694. ScienceDirect notes that the most commonly used deboning machines, such as those made by Baader and Bibun, work by pressing fish parts against perforated surfaces to extract the meat. The mince produced is packed in poly-lined cartons and stored at −40°C until further use.

Utilizing low-value and small-bodied fish 🔗

One of the most important practical advantages of the mechanical method is what it does for fish that are otherwise difficult or uneconomical to process. Small-bodied species – sardines, anchovies, lizard fish, pink perch, jewfish – are too small or too bony to fillet by hand efficiently. At the same time, industry market analysis confirms that fish deboning machines are specifically designed to increase the economic value of low-value fish, dividing larger fish into segments before processing while collecting meat directly from smaller fish without pre-cutting.

The peer-reviewed research on small-scale deboner development makes the point directly: one possible way to utilize under-utilized and bycatch fish species in countries like India is through isolation of meat and the development of value-added products such as surimi, sausages, and fermented products. The FAO’s Asia-Pacific fisheries review describes how low-value or trash fish – typically small in size, with low flesh ratios and low consumer preference – have been difficult to process profitably by hand. Mechanical deboning changes that equation by extracting usable mince from fish that would otherwise be discarded or turned into fishmeal.

Comparing the two methods 🔗

The manual and mechanical methods serve different production contexts, and understanding the practical differences helps in choosing the right approach. Manual production requires minimal capital investment and offers flexibility – it can be adapted to different fish types and batch sizes without reprogramming a machine. However, it is slow, labour-intensive, and inconsistent in output quality. Yield is also lower, particularly from bony or small fish where hand-picking recovers only a fraction of the available meat.

Mechanical production, on the other hand, delivers speed, consistency, and much higher yields. Commercial deboning machines can process between 180 and 2,000 kg per hour depending on the model, and the extracted flesh is discharged separately from bones and skin in a continuous process. The mince produced is soft, boneless, and immediately ready for further processing. The tradeoff is the upfront cost of the equipment and the need for maintenance and trained operators. The FAO notes that filleting machines for marine fish are quite costly and not always suitable for freshwater species, which means equipment selection must account for the species being processed.

For large-scale operations processing high volumes of low-value fish, mechanical deboning is the clear choice. For artisanal processors, community-level fisheries, or operations handling high-value whole fish where portion integrity matters, manual methods retain their relevance. In practice, many processing facilities use a combination – mechanical deboning for frames and trimmings, and manual filleting for premium whole-fish products.

From mince to product 🔗

Once the fish mince is produced – whether manually or mechanically – the resulting material is a soft, paste-like flesh ready for formulation into finished products. It can be washed to remove blood, enzymes, and soluble proteins (a step that transforms it into surimi), or it can be used directly in the production of fish balls, fish cakes, fish sausages, fish noodles, or patties. The World Food Logistics Organization highlights that mechanically deboned fish is particularly versatile because mincing removes species recognition, allowing any edible species to be used alone or in combination to create the most desirable product. The mince can also be preserved with cryoprotectants such as sucrose, sorbitol, and polyphosphates to extend frozen shelf life and maintain functional properties.

What do you think? Given the clear efficiency advantages of mechanical deboning, should small-scale coastal fisheries invest in shared community-level deboning machines to better utilize low-value bycatch? And as demand for processed seafood grows globally, how do you think the balance between manual craftsmanship and mechanical efficiency will shift in the coming decade?

References

1. https://www.sciencedirect.com/topics/food-science/minced-fish
2. https://www.gcca.org/legacy-system/WFLO-Commodity-Storage-Manual-2018Fish_~_Comminuted,_Deboned_and_Minced%5B1%5D.pdf
3. https://www.fao.org/4/w0495e/w0495e03.htm
4. https://www.fao.org/flw-in-fish-value-chains/value-chain/processing-storage/en/
5. https://www.takemefishing.org/how-to-fish/how-to-catch-fish/how-to-fillet-a-fish/
6. https://www.thekitchn.com/how-to-fillet-fish-23727071
7. https://egyankosh.ac.in/bitstream/123456789/9832/1/Unit-1.pdf
8. https://pmc.ncbi.nlm.nih.gov/articles/PMC3671064/
9. https://www.meat-machinery.com/fish-processing-machinery/fish-meat-separator.html
10. https://www.futuremarketinsights.com/reports/fish-deboning-machine-market
11. https://www.fao.org/docrep/008/ae934e/ae934e04.htm