ShareIs super-cooling better than chilling for seafood products?
Super-cooled storage is a novel technique that better preserves the texture and freshness of fish and extends shelf life compared to chilling.
Global production of aquatic products was estimated at 178 million tonnes in 2020, representing a sale value of USD 406 billion. [1]
According to IIR member DNV, the global production of marine seafood (including fishery and aquaculture) is forecast to increase by 20% by 2050. [2] In many regions, seafood demand per capita is expected to increase faster than consumption of terrestrial meat and vegetarian foods, such as plants, eggs, and milk. However, the lack of cold chain infrastructure represents the main barrier to this growth in regions such as Sub-Saharan Africa or India.
Indeed, freezing is the main method of preserving fishery and aquaculture products for food purposes, accounting for 63% of all processed aquatic animal production for human consumption. [1] Previously frozen fish is often defrosted and sold chilled, which can lead to a drastic decrease in quality.[3] Methods of low-temperature preservation of food include freezing, chilling, controlled freezing point storage, super-chilling, and super-cooling. Super-cooled storage is a novel preservation method that stores food below the freezing temperature without forming ice crystals. [3]
According to a review article published in IJR, super-cooled storage could be an interesting alternative to chilling, offering longer shelf life and lower temperature to inhibit microbial activity.
Fish typically have a 5 to 10-day shelf life throughout logistics and marketing, as they are stored chilled. A study has shown that super-cooled fresh tuna can be stored at -3.2°C for 8 days in a non-frozen state, extending the shelf life by 230% in comparison to normal chilling. [4] Studies also indicate that bacterial growth is significantly lower following several days of super-cooled storage at -1°C, compared with storage at 1°C.
Maintaining the super-cooled state is the biggest challenge for this technique as it requires to keep the temperature lower than the initial freezing point, but higher than the nucleation point. Moreover, the freezing point temperature and the attainable degree of super-cooling differ for each aquatic product, so it is difficult to determine an accurate freezing point to cover all species.
Liu X-Y et al. believe that technologies such as using cryoprotectants, controlled cooling rates and applied physical fields can help achieve precise regulation of freezing and nucleation points of aquatic products.
Sources
[1] FAO. 2022. The State of World Fisheries and Aquaculture 2022. Towards Blue Transformation. Rome, FAO. https://doi.org/10.4060/cc0461en
[2] DNV. Seafood Forecast to 2050. https://www.dnv.com/news/dnv-launches-seafood-forecast-to-2050-at-cop28-251303
[3] Liu, X. Y., Zhang, X. L., Wang, G. B., Mo, F. Y., & Zhang, X. R. (2023). Application of super-cooled storage of aquatic products: A review. International Journal of Refrigeration. https://doi.org/10.1016/j.ijrefrig.2023.06.022
[4] Kang T, Shafel T, Lee D, Lee CJ, Lee SH, Jun S. Quality Retention of Fresh Tuna Stored Using Supercooling Technology. Foods. 2020; 9(10):1356. https://doi.org/10.3390/foods9101356