Innovations in Fish Meal Production Techniques

Fish meal is one of the most important feed ingredients used in aquaculture, poultry, and livestock nutrition. It delivers high-quality protein, essential amino acids, omega-3 fatty acids, and vital minerals that support animal growth and health. But making fish meal is not a simple task – the production process directly affects the nutritional value of the final product. In recent years, the industry has undergone significant technological upgrades aimed at improving product quality, energy efficiency, and sustainability. These innovations are reshaping how fish meal is manufactured, especially for demanding applications like aquaculture feed.

Why fish meal quality matters 🔗

Fish meal typically contains between 60% and 72% crude protein, making it one of the most nutrient-dense feed ingredients available. According to the University of Florida’s IFAS Extension, the overall protein digestibility of fish meal consistently exceeds 95%, far outperforming most plant-based protein sources. Its amino acid profile is particularly well-balanced, supplying all ten essential amino acids required by fish – including lysine and methionine, which are often limiting in plant proteins.

However, this nutritional richness is fragile. The high levels of polyunsaturated fatty acids (PUFAs) in fish meal make it extremely prone to oxidation when exposed to heat, air, or light. If the drying and processing steps are not carefully managed, the result is degraded nutrients, reduced energy content, and compromised feed quality. As the Global Seafood Alliance has noted, without proper antioxidant stabilization, the available energy in fish meal can drop by as much as 20%. In extreme historical cases, uncontrolled oxidation has even caused spontaneous combustion of stored fish meal.

Traditional fish meal production: the basics 🔗

The conventional process for making fish meal follows a well-established sequence: cooking, pressing, drying, and grinding. Raw fish – typically small pelagic species like anchovies, sardines, menhaden, and herring – is first cooked in a steam-jacketed screw conveyor. This step coagulates the tissue proteins and sterilizes the material. Next, the cooked material is pressed to separate the liquid fraction (a mixture of oil, water, and soluble proteins) from the solid residue known as “presscake.”

The liquid fraction is centrifuged to extract fish oil, and the remaining liquid – called stickwater – is evaporated into a thick concentrate. This concentrate can be sold separately or added back to the presscake to create “whole” fish meal. Finally, the material is dried, ground, and packaged for storage and transport.

The drying stage is where things get tricky. Traditional direct-fired dryers blow very hot air over the meal as it tumbles inside a rotating drum. While this method is fast, it carries a major risk: overheating. If not precisely controlled, direct heat can scorch the meal, denature proteins, destroy heat-sensitive vitamins, and accelerate oxidation of the remaining fats. The result is a lower-grade product with reduced digestibility and nutritional value.

Indirectly heated steam dryers: a game-changer 🔗

One of the most important innovations in modern fish meal manufacturing is the shift from direct-fired drying to indirectly heated steam dryers. These systems use steam as the heat source, but the critical difference is that the steam never comes into direct contact with the fish meal. Instead, heat is transferred through a metal surface – typically rotating discs or a jacketed cylinder – that separates the heating medium from the material being dried.

How disc dryers work 🔗

The most widely used type of indirect steam dryer in fish meal processing is the disc dryer. This technology was originally developed in the 1960s by the Stord Bartz Company in Norway and has since become a standard in modern fish meal plants worldwide. In a disc dryer, double-walled discs are mounted on a central rotating shaft inside a horizontal shell. Saturated steam – typically at a pressure of around 0.6 MPa – flows through the hollow interior of these discs, heating them from the inside. The wet fish meal is fed in at one end and slowly moves across the heated disc surfaces, with moisture evaporating through indirect contact. Stainless steel scrapers positioned between the discs keep the material moving and prevent it from sticking or clumping.

The spindle rotates slowly, usually at just 10-12 RPM, giving the material a gentle and extended exposure to heat. The evaporated moisture is collected and vented through a vapour dome to an exhaust purification system. The dried product exits through a discharge screw conveyor at the opposite end. According to TG Machines, an equipment manufacturer specializing in rendering and fish meal systems, the large surface area of the disc design delivers high thermal efficiency while keeping the material at controlled temperatures.

Advantages over direct drying 🔗

The benefits of indirect steam drying over conventional direct-fired methods are significant:

Precise temperature control – Because the heat transfer happens through a metal wall, the material is never exposed to the extreme temperatures of open flame or superheated air. This reduces the risk of overheating, scorching, and protein denaturation.

Better nutrient preservation – Lower and more uniform drying temperatures help retain the essential amino acids, omega-3 fatty acids, and vitamins that make fish meal nutritionally valuable. This is especially important for premium aquaculture feeds where nutritional integrity directly impacts fish growth and health.

Higher energy efficiency – Indirect dryers recover and reuse heat more effectively. Some advanced systems compress the steam generated during drying and recirculate it as a heating medium, dramatically reducing total energy consumption. A patent filed for an indirect drying method described energy consumption as low as 350 kWh per 1,000 kg of fish – compared to an average of 840 kWh per 1,000 kg in conventional plants at the time.

Reduced environmental impact – The enclosed design of indirect dryers helps contain odours and emissions, a persistent challenge in fish meal production. Since the drying happens in a sealed system, volatile compounds are easier to capture and treat before release.

Advanced cooling systems 🔗

Drying is only half the equation. What happens immediately after drying is just as important for final product quality. If hot fish meal is packaged or stored without adequate cooling, residual heat can trigger continued oxidation, moisture migration, and even microbial growth.

Modern cooling systems are designed to rapidly and uniformly bring the temperature of dried fish meal down to safe storage levels. These systems typically use ambient or refrigerated air passed through the meal in a controlled manner – often in a rotary cooler or a counter-current air cooler – to remove heat without reintroducing moisture.

Proper cooling serves several functions. First, it halts the oxidation process that accelerates at elevated temperatures. Second, it stabilizes the moisture content, ensuring the meal does not reabsorb water from the environment. Third, it produces a more uniform final product, which translates to consistent quality across batches. For producers targeting the high-value aquaculture feed market, this consistency is essential.

The role of antioxidants in modern fish meal production 🔗

Even with improved drying and cooling, fish meal remains vulnerable to oxidation during storage and transport due to its high PUFA content. This is where antioxidants play a critical role. As explained by the Global Seafood Alliance, antioxidants work by donating free electrons to stabilize the reactive free radicals that drive oxidation. They stop the chain reaction of oxidation but cannot reverse damage already done – which is why early application is essential.

In practice, antioxidants are applied at two key points: before cooking (to protect the raw material during initial processing) and after cooling (as a top-dressing to protect the finished meal during storage). The most commonly used synthetic antioxidant in the fish meal industry has historically been ethoxyquin, typically applied at around 750 ppm, adjusted based on the fat content of the raw fish.

However, there is a growing shift toward natural antioxidants. Research published in Biology (MDPI) highlights the increasing use of carotenoids, polyphenols, tocopherols, and flavonoids in aquaculture feeds. These natural compounds not only protect against oxidation but also offer additional health benefits to the animals consuming the feed, including enhanced immune responses and improved stress tolerance.

Two-stage drying: combining speed with quality 🔗

Another notable advancement is the adoption of two-stage drying systems. In this approach, the first stage uses a low-pressure steam dryer to remove the bulk of the moisture gently. Because the system operates under lower steam pressure, the drying temperature is significantly lower – approximately 30°C less than conventional dryers. This protects the digestibility of the fish meal protein during the critical initial drying phase.

The second stage then uses hot air drying at controlled temperatures to bring the moisture content down to the target level (typically around 8-10%) for safe storage. By splitting the drying process into two phases, manufacturers achieve faster throughput without compromising product quality. This method is particularly effective for producing low-temperature (LT) fish meal, a premium grade that commands higher prices in the aquaculture feed market due to its superior protein digestibility and nutrient retention.

Automation and digital monitoring 🔗

Modern fish meal plants are also benefiting from automation and digital process control. IoT-enabled sensors can now monitor temperature, moisture content, and product flow in real time throughout the production line. This data allows operators to make precise adjustments to drying times, steam pressures, and cooling rates, minimizing human error and maximizing consistency.

Some advanced facilities also use AI-based systems to predict optimal processing parameters based on the characteristics of the incoming raw material – such as species composition, fat content, and freshness level. This is important because raw material quality varies significantly depending on the catch, season, and storage conditions before processing. Automated systems help account for these variations and deliver a more uniform final product.

Growing global demand drives innovation 🔗

The push for better fish meal production technology is driven by strong market fundamentals. According to IFFO, the Marine Ingredients Organisation, cumulative global fish meal production in the first nine months of 2024 rose by nearly 23% compared to the same period in 2023, largely thanks to a successful anchovy season in Peru. Globally, the fish meal market is projected to grow at a compound annual growth rate of over 4% through 2035, with aquaculture as the primary demand driver.

At the same time, the total global supply of fish for reduction into meal remains finite. Wild-caught fish – primarily anchovies, menhaden, capelin, and sardines – still account for over 65% of all fish meal produced. This means producers must extract maximum nutritional value from every tonne of raw material. Improved drying, cooling, and preservation technologies directly serve this goal by reducing nutrient loss during processing.

There is also a growing contribution from fish processing by-products – heads, bones, trimmings, and offal from filleting and canning operations. Research published in Science Advances notes that fish meal yields typically range between 16% and 25% by weight of the raw material, with improved production methods potentially pushing this figure to 23.5-24.5%. Using by-products as raw material not only increases overall supply but also supports a more circular approach to seafood processing.

Impact on aquaculture feed quality 🔗

All of these innovations ultimately serve the aquaculture industry, which consumes the majority of global fish meal production. High-quality fish meal – with intact amino acids, well-preserved omega-3 fatty acids, and minimal oxidation damage – translates directly into better feed conversion ratios, faster fish growth, and improved disease resistance in farmed species.

For species like salmon and shrimp, where fish meal inclusion rates can be quite high and the animals are particularly sensitive to feed quality, the difference between conventionally processed and low-temperature steam-dried fish meal can be measurable in growth performance and survival rates. As NOAA Fisheries has highlighted, ongoing research into improved feed formulation and ingredient quality remains central to the sustainable growth of aquaculture worldwide.

Looking ahead: what’s next for fish meal production? 🔗

The future of fish meal manufacturing will likely see further integration of several trends. Vacuum packaging and modified atmosphere packaging are being explored to extend shelf life and reduce oxidation during transport. Alternative raw material sources – including insect protein and single-cell proteins from microalgae and bacteria – are being developed to supplement traditional fish-based inputs. And continued improvements in heat recovery, waste heat utilization, and closed-loop steam systems will push energy efficiency even further.

The industry is also moving toward greater traceability and certification. Programmes like the IFFO Responsible Supply (IFFO RS) standard are encouraging producers to adopt best practices in sourcing, processing, and quality management. As buyers – particularly large aquaculture operations and feed companies – demand more transparency, fish meal producers who invest in modern technology and quality systems will be best positioned to compete.

What do you think? With fish meal demand rising and raw material supplies limited, which production innovation do you believe will have the greatest impact on feed quality in the next decade? And how important is it for the industry to shift toward using more by-products and alternative ingredients alongside improved processing technology?

References

1. https://edis.ifas.ufl.edu/publication/FA122
2. https://www.globalseafood.org/advocate/antioxidants-manage-effects-of-oxidation-on-feeds-feed-ingredients/
3. https://tg-machines.com/disc-dryer
4. https://patents.google.com/patent/WO1983003042A1/en
5. https://www.mdpi.com/2079-7737/14/1/87
6. https://www.iffo.com/2024-fishmeal-production-higher-2023-so-far-due-perus-strong-anchovy-seasons
7. https://www.science.org/doi/10.1126/sciadv.adn5650
8. https://www.fisheries.noaa.gov/insight/feeds-aquaculture