From Sea to Freezer – Skipjack Tuna Processing: A Step-by-Step Guide

Skipjack tuna is a staple in the global seafood market, particularly in the canned tuna industry. Known for its mild flavor and high protein content, skipjack tuna is widely caught in Indonesia and processed for both domestic and international markets. The journey from sea to freezer is a complex one, involving multiple stages to ensure the fish maintains its quality and safety. In this blog, we’ll explore the entire skipjack tuna processing chain, from the moment it’s caught to when it’s safely stored for future use.

1. Catching Skipjack Tuna

The first step in the skipjack tuna processing journey begins in the deep waters of the Pacific and Indian Oceans. Indonesian fishermen use sustainable methods such as pole-and-line fishing and purse seining to catch skipjack tuna in large quantities. These fishing methods help minimize bycatch and reduce the impact on marine ecosystems.

Skipjack tuna, unlike other species like yellowfin or bigeye, tends to swim in schools closer to the surface, making it easier to catch in bulk. Once the tuna is caught, the clock starts ticking – the fish must be handled quickly and efficiently to maintain its freshness.

2. Onboard Handling and Preservation

Immediately after the tuna is caught, it is transferred to onboard storage areas, where it is preserved using ice or refrigerated seawater. This is a critical step, as the quality of the tuna depends on how fast it can be cooled down after being caught.

Fishermen often follow strict hygiene protocols to ensure the tuna remains free from contamination. The goal is to maintain the fish at an optimal temperature to slow down bacterial growth and prevent spoilage. This initial preservation step is key to retaining the tuna’s texture and flavor, which are essential for consumer satisfaction.

3. Transport to Processing Facilities

Once the tuna reaches the shore, it is transported to processing facilities. The transportation is done under strict temperature control, usually in refrigerated trucks, to maintain the cold chain. Any lapse in temperature control can result in the fish losing quality or becoming unsafe for consumption.

At the processing facility, the tuna is unloaded, inspected, and sorted based on size and quality. This stage is vital for ensuring that only the best fish move forward in the processing chain, while lower-grade tuna may be used for other purposes or discarded.

4. Cleaning and Butchering

The first step in the facility involves cleaning the tuna thoroughly. The fish are washed with clean, cold water to remove any debris, slime, or blood. Following the cleaning process, the tuna is butchered. This step involves cutting the fish into manageable portions for further processing. The tuna is gutted, and its head, fins, and other non-edible parts are removed. In many cases, the skipjack tuna is cut into loins, which are the prime parts used for canning or freezing.

This process is done with care to minimize waste and ensure that the valuable parts of the fish are preserved for consumption. Fish parts that are not used for human consumption are often processed into fishmeal, ensuring minimal waste from the entire process.

5. Freezing and Preservation

Once the tuna has been butchered, it moves to the freezing stage. Freezing is an essential part of tuna processing, as it ensures the fish remains safe to eat and retains its nutritional value. Two common methods are used:

• Blast Freezing: The tuna is rapidly frozen at extremely low temperatures (as low as -40°C). This method is fast and ensures that the fish retains its freshness, texture, and flavor without forming large ice crystals, which can damage the flesh.
• Brine Freezing: This method involves placing the tuna in supercooled brine, freezing it quickly. While effective, this method can sometimes result in a slightly different texture, depending on the duration and temperature.

The frozen tuna is then packed into vacuum-sealed bags or placed in airtight containers to protect it from freezer burn and moisture loss. The vacuum-sealing process also prevents oxidation, which can affect the flavor of the fish.

6. Quality Control and Inspection

Before the tuna is released for storage or shipping, it goes through a thorough quality control inspection. This ensures that the fish meets both national and international standards for food safety and quality. The tuna is tested for factors like temperature, texture, and microbial presence.

Many facilities also follow international standards such as HACCP (Hazard Analysis Critical Control Points) and may hold certifications like the Marine Stewardship Council (MSC) for sustainable fishing practices.

7. Storage and Distribution

After the tuna is processed and frozen, it is stored in large, temperature-controlled freezers until it is ready for shipment. Tuna is often kept at -18°C or below to ensure its longevity and safety for consumption. The frozen tuna can be stored for extended periods without losing its quality, making it an ideal product for global distribution.

Once the tuna is packed and ready for shipping, it is distributed to various markets around the world. Indonesia is a major exporter of frozen skipjack tuna, with markets in Japan, the United States, and Europe being the largest importers.

Conclusion

The journey of skipjack tuna from the sea to freezer is a highly regulated and intricate process. It involves careful handling at every stage, from catching the fish to ensuring it is properly frozen and stored for consumption. The Indonesian tuna industry has become a global leader in this process, thanks to its commitment to quality and sustainability. Skipjack tuna is an important resource, not only for consumers but also for the thousands of people employed in the fishing and processing industries.