Techniques to save energy in the cold chain, including processing and cooling methods, were explored at a seminar in Solihull in the West Midlands last week.
The event was organised by the Food Refrigeration and Process Engineering Research Centre (FRPERC), Bristol University, and sponsored by the Department for Environment, Food and Rural Affairs and the Carbon Trust.
“The interaction between food processing and refrigeration is not something many are going into at the moment,” said Judith Evans, FRPERC senior research project manager. “Thinner products, improving the heat transfer co-efficient, offer benefits, and there are benefits in two-stage chilling, bringing the surface temperature down fast, then working on the core temperature.”
The physical nature of products could affect the way in which they could be chilled and frozen said Evans - the issue would affect pies with air gaps, for example.
There was considerable further potential for ambient cooling - after cooking, food could be left to cool by as much as 30-40°C in controlled conditions before further freezing or chilling. “If you increase the cooling time by a small amount - it has to be done properly - there is very little effect on food safety,” said Evans.
The energy needed to further lower the temperature of food cooled in this way was significantly less than that used to chill or freeze food at an earlier point. Air cycled from the existing factory environment could be used in this process.
“There are still quite low levels of monitoring equipment,” said Evans. “There’s a huge area for training on measuring energy use - how and where you should do it and what you should do with it when you get that data.”
Freeze-drying and adsorption techniques offered quicker and more energy-efficient ways of freezing food, said Evans. However, the cost of such technology was still high.
Some of the biggest problems leading to inefficient use of freezer and chiller equipment included processors buying the wrong equipment for the job and poor staff training in kit use. Lack of properly trained staff was also an issue, leading to equipment being improperly maintained.
The three-year FRPERC project was finishing at the end of June, said Evans, and findings were being made available at the website http://www.frperc.bris.ac.uk. The work had formed a springboard for spin-off pilot energy saving programmes. However, the project organisers needed the input of processors to progress in many areas.
Evans also invited processors that had studied energy conservation in freezing and chilling, from initial processing to transportation, to feed their findings into the FRPERC group. Interested parties can email Judith Evans.