Fresh Mussel Canning: Process and Machinery

The mussel is one of the most versatile seafood products. Its wide range of canning and final presentation possibilities makes it one of the most in-demand shellfish in the market.

The processing of mussels intended for the fresh market, typically packaged in nets or trays, shares the initial steps with molluscs canning and freezing lines, as the raw material must be thoroughly cleaned and sorted. The primary goal of the fresh line is to maintain the cold chain and prepare the product for a short shelf life after distribution.

Reception and Initial Preparation of Mussels

Initially, the process begins similarly to other mollusc preparations: mussels are unloaded at the plant, and marine debris is separated. Mussels arrive at the factory from farms (rafts or long-lines) in bulk trucks or plastic bins. They can arrive loose (detached) or in clusters (clusters held together by byssus threads and fouling), depending on the previous equipment used in farming. What processes follow?

• Degraining and Washing. If the mussels arrive in clusters, it is necessary to separate the bunches using a mussel decumpler. At Gaictech, this machine is equipped with two modules: a degraining drum and a classifying and washing drum. Then, they are washed thoroughly with water to remove marine debris (seaweed, stones, large clumps of byssal threads, etc.). Additionally, a preliminary sorting is performed to discard mussels smaller than 14-15 millimeters, which are considered waste or seeds.
• Size Classification. The cleaned mussels are sorted by size (small, medium, and large). For this purpose, Gaictech manufactures a mussel grader with divergent rollers that offer up to three levels of calibration by the contour of the piece. Medium and large-sized mussels are most commonly used for fresh presentations and half-shell.

Throughout this initial process, it is advisable to use transport systems and hoppers made of durable and stainless materials, suitable for promoting hygiene and withstanding abrasion.

External Cleaning of the Pieces

For mussels, the final presentation is crucial, so good cleaning of the pieces is key to achieving the ideal outcome. Following the initial sorting and cleaning, more specific phases occur:

• Debearding. In this stage, the byssus or beard of the mussel is removed from the shell exterior. This process is important to eliminate a significant amount of beard and achieve a more appealing exterior appearance of the mussel. Gaictech’s mussel debearding machine is particularly efficient for this task, as it can adapt to the client’s production volume (up to a maximum of 3,000 kg per hour).

  

  

• Shell Brushing. This process removes all marine debris and white deposits adhered to the shell to improve the product’s exterior presentation. A mussel brusher is essential for this task, which at Gaictech, can also be adapted to different production volumes.

  

  

Cooling of Mussels

At this stage of the process line, the procedures differ depending on the final presentation of the product. For fresh mussels, maintaining the product’s temperature is crucial to ensure proper preservation before packaging in nets, bags, or trays.

After brushing and debearding, the mussels must be quickly cooled to ensure that the product’s temperature does not exceed 10°C (ideally remaining between 5°C and 10°C). This ensures that the mussels are ready for continuous weighing and packaging.

This is where the mussel chiller comes into play. The equipment consists of a stainless steel tank insulated with polyurethane to maintain temperature and reduce energy costs.

The Gaictech cooler is equipped with a cooling coil and a standalone refrigeration unit designed to continuously cool the water stored in the tank. Additionally, it features an ozone disinfection system that cleans and disinfects the water, keeping it in optimal hygienic conditions throughout working hours. The product is conveyed via a modular belt with pushers. The cooling process lasts several minutes, after which the mussel is ready for packaging.

In this stage of the process, it is possible to integrate auxiliary machinery, such as a reject sorting unit capable of identifying, through a combination of multiple technologies, broken or defective mussels or those outside a predetermined size range. When the machine detects a broken mussel, it removes it using compressed air, allowing for differentiation of damaged products and optimizing production and subsequent inspection labor.

Final Packaging and Distribution

After ensuring an optimal temperature, the fresh mussel is ready to be packaged in nets or trays. There is specific machinery for this process, and at Gaictech, we integrate any type of packaging solution for molluscs: nets, trays, etc.

This process typically involves equipment such as fillers (both automatic and semi-automatic) as well as other machinery for weighing and sealing. While the most common presentation of fresh mussels is in nets, the plastic tray format with heat sealing is also gaining popularity. Plastic trays are often used for modified atmosphere packaging to slightly extend the refrigerated shelf life.

Once packaged, the product is ready for the fresh market, with a shelf life of approximately one to three days, depending on the presentation.