Supercooling and superchilling: A solution to increased shelf life and reduced food waste?
Supercooling and superchilling may increase the shelf life and reduce food waste.
If these technologies were combined with perfusion chilling for meat and fish, then additional benefits such as rapid cooling, low weight loss and novel products could result.
Begun in September 2010, FRISBEE (Food Refrigeration Innovations for Safety, consumers’ Benefit, Environmental impact and Energy optimisation along the cold chain in Europe) was a four-year European Union funded project which objectives included providing new tools, concepts and solutions for improving refrigeration technologies along the European food cold chain.
The project developed new innovative mathematical modelling tools that combine food quality and safety together with energy, environmental and economic aspects in order to predict and control food quality and safety in the cold chain.
As work package leader for dissemination, the IIR published a handbook (pdf format) entitled “Needs and Expectations of European Consumers and Industry regarding Refrigeration” which summarizes the outcomes of the FRISBEE project targeting the general public, consumers and industrials.
As mentioned in the information disseminated via the FRISBEE project*, market opinion remains that fresh foods are better than frozen foods. Thus, demand is increasing to keep food fresh, making requirement for keeping the right temperatures essential. In this context, superchilling and supercooling have enormous potential to enable safe, high quality and long term storage of foods without the consumer perceived detrimental effects of freezing.
Supercooling is the process of lowering the temperature of a product below its usual freezing point without ice formation. In the case of superchilling, the temperature is reduced to around -2°C and some of the water in the product is frozen.
Supercooling: a promising storage technique for pork
In the research paper “Development of supercooling as a storage technique for pork” based on experimental abattoir trials presented by J. Evans and G. Stonehouse during ICR2015, demonstrates the potential of supercooling in pork. Trials were carried out to compare storage life of pork meat which had been supercooled with samples that had been superchilled and conventionally chilled.
The experimental abattoir trials demonstrated that supercooling in pork is possible. The quality of superchilled and supercooled samples was very similar, the only difference being a greater drip loss from the superchilled samples. Therefore, with further development, supercooling could potentially be applied as a future chilling technology for pork processing to control product temperature and extend shelf life. As supercooling without subsequent nucleation could only be achieved at ambient temperatures above -3°C any process developed would require relatively high air temperatures in comparison with a comparable process such as superchilling. This would be advantageous in terms of energy use (high evaporating temperatures) but may not be such a rapid process. Due to the lack of ice nucleation, the energy required for supercooling would be less than comparable processes where ice is formed and, this again, would be an energy benefit.
Available for download in FRIDOC
Superchilling can extend shelf life of prawns by up to 120%
Campden BRI in UK showed that superchilling could increase the shelf life of cook-chill prawns to 22 days. This offers a potential 120% increase on the 10 day chilled shelf life subject to the protocol being implemented commercially. In addition to extending shelf life, Campden BRI claims that superchilling can also reduce energy use and waste. Campden BRI calculated the energy required to produce and distribute both superchilled and chilled farmed salmon. Although superchilling fish requires more energy during manufacture, more fish can be packed into each vehicle - because superchilling negates the need for ice during transportation – decreasing the number of required journeys. The extra energy used to superchill rather than chill was equalled in fuel savings by the time the fish had been driven the 477km from Stornoway to Glasgow.
The extended storage life also provides the opportunity to make chilled product to stock rather than to order, limiting waste from over-production that is not immediately dispatched.
Optimum preservation process conditions for superchilling of pork and salmon
In the FRISBEE project, SINTEF (The Foundation for Scientific and Industrial Research) in Norway identified optimum preservation process conditions for superchilling of pork and salmon, including ice content, temperature level and cooling rates, and assess effect of process conditions on quality.
During autumn 2011, experimental work in lab and pilot scale was performed on salmon
Activities planned were measurements of temperature, ice content, microbial load (spoilage bacteria) and quality measurements due to different chilling technologies through cold chain to retail cabinets for:
- Traditional chilled salmon.
- Superchilled salmon in impingement freezer.
- Superchilled salmon in CBC (Contact Blast Chiller)
The results from these experiments were used to attempt to complete final models for safety and quality aspects of chilled and superchilled salmon as functions of time and temperature.