Superchilling to improve quality and shelf-life
Greg Jones, Food Microbiologist
Members have voted for a new project on superchilling for improved product shelf-life and quality. Previous work has demonstrated its considerable potential. This new project will provide manufacturers and retailers with clear evidence of which products could benefit most from use of superchilling. Listen to Greg Jones explaining what the technique is and its potential benefits.
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Superchilling is the practice of taking a product down to below the temperature at which it would usually be chilled, down to about minus one and a half to minus two degrees C, at this point part of the product is frozen and part of it is liquid.
Superchilling allows one to extend the shelf-life of the product. For example, we looked at some prawns, we took those in at superchill temperatures, kept them at superchill temperatures for 10 days and then proved that they had a subsequent chilled shelf life of 10 days. This effectively doubled the shelf life of those prawns.
The methodology is very, very simple, all you need is a standard blast chiller and current mechanical refrigeration techniques are well able to hold at minus one and a half to minus two degrees C. So, it really is a case of leaving a product in a standard chiller for a slightly longer time before then moving it into a standard cold storage area running at a slightly colder temperature than usual.
Our experiments so far have shown that it is safe, we have done a limited number of experiments to show that Listeria does not grow at superchill temperatures. However, if one is following a good HACCP plan then the products should be safe anyway, so superchilling does not make a product any less safe it really is dependent on the product and how it is manufactured when it comes to safety.
Challenges can be establishing when a product reaches that point at which it is partially frozen rather totally frozen, and then another challenge is to maintain superchill temperatures in storage whilst the product is under control of the manufacturer. This can be achieved using standard refrigeration units and we have done that here at Campden BRI and we have not found it to be too great a challenge.