Packaging frozen seafood presents different challenges from fresh: materials must remain flexible and maintain barrier at -18°C, ice must not compromise sealing, and shelf life must reach 18-24 months to justify the cold chain.
Materials and films for frozen products
Films for low-temperature packaging must maintain flexibility and barrier even at -25°C. The most used materials are PA/PE (nylon/polyethylene) for vacuum and PP/PE or PET/PE for trays. OPP (oriented polypropylene) is not recommended below -5°C as it becomes brittle.
- Embossed PA/PE: cryo-resistant vacuum film, ideal for irregular pieces
- PET/PE: sealed trays, good barrier, cryo-resistant
- PP/PE: economical trays, suitable down to -18°C
- EVOH barrier film: reduces oxidation (freezer burn)
- Protective glaze (glazing): alternative to film for whole fish
Packaging technologies for frozen products
Vacuum is the most used technology for individual frozen seafood products (fillets, prawns, octopus): it eliminates air that would cause freezer burn and fat oxidation. For IQF (Individually Quick Frozen) and small products, bags with clips are used. For pre-formed portions (fish fingers, fish cakes), thermoformers with trays are used.
- Vacuum fillets and steaks: chamber or thermoformer, shelf life 18-24 months
- IQF prawns and shellfish: clip bag + nitrogen, shelf life 12-18 months
- Fish fingers and fish cakes: thermoformer or tray sealer, shelf life 12-18 months
- Whole fish: tray + shrink film or glazing
Operational challenges of low-temperature packaging
The main problem with frozen packaging is ice forming on sealing surfaces, preventing an airtight closure. Machines must operate in cold environments (+2/+8°C) and sealing parameters (temperature, time, pressure) must be calibrated accounting for product and film temperature.
- Sealing temperature 10-15% higher than for fresh product
- Drying product before packaging: reduces ice on seal
- Machines with zone-controlled bar heating: precise adaptation
- Seal integrity test at -18°C: mandatory for seal validation
Packaging frozen seafood products?
Our chambers and thermoformers are tested for cryogenic applications too. Contact us for a consultation.
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