The process of superchilling involves reducing the temperature of foods to around -2°C so they become partially frozen. The products can then be stored at that temperature until being released into the chill chain.
According to the findings, the greatest extension in shelf-life was achieved with prawns, where superchilling could increase the shelf-life of cook-chill prawns to 22 days. This offered up to a 120% increase on the 10-day chilled shelf-life subject to the protocol being used commercially. The effects of superchilling on poultry and gammon were also tested.
“Superchilling is not a novel technique. It is used on an ad-hoc basis to build stock in times of high demand, such as Christmas or a ‘barbecue’ weekend,” said Dr Greg Jones, a microbiologist at Campden BRI and the project coordinator.
‘Without compromising quality’
“Up until now, there has been little data to supps use more widely and little information on the impact of its wider use on product safety. Our research shows that it can be used to extend shelf-life without compromising quality or safety.”
Campden BRI also demonstrated that superchilling could reduce energy use and waste.
Researchers 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 so fewer journeys were required.
The extra energy used to superchill rather than chill was equalled in fuel savings by the time the fish had been driven the 445km from Stornoway to Glasgow.
Extended storage life
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.
Further advantages identified included a longer ‘minimum life on receipt’ for retailers, reduced start-up and shut-down losses due to the possibility of longer production runs, and a reduction in overtime payments from reducing weekend workload.
The research was part of Department for Environment, Food and Rural Affairs-funded project in conjunction with industrial partners Marks & Spencer, Pinguin Foods, Lyons Seafoods, The Scottish Salmon Company, Tulip and the poultry processor Moy Park.