Person putting food waste in a bin

Reducing food waste using cold plasma technology

The word ‘plasma’ is usually associated with the sci-fi worlds of fusion energy. But harnessing this natural form of matter could benefit food waste reduction for astonishingly low prices, helping producers and consumers across the world to boost food security, increase resilience, and reduce inequality.

This innovative technology can also sterilise medical devices in the healthcare sector, bringing unique and cost-effective advantages to patients and practitioners.

It all revolves around plasmas, which are often described as the fourth natural state of matter after liquid, solid or gas. “All you need is air, and if you apply an electrical voltage in a clever way you get a plasma,” says the University of Liverpool’s Dr James Walsh, who leads the plasma generation side of the project at Liverpool’s new Centre for Plasma Microbiology. “This plasma is a mix of electrons, ions and reactive chemicals that can react with microbes like bacteria and kill them very quickly.”

Benefits of using plasma technology in food production

Cleansed of microbes in seconds, the result is food with much improved shelf life which could save millions of pounds of produce per day in the UK. The plasma used is safe and early tests suggest it does not affect the food’s taste or nutritional profile, and has many advantages over existing treatments. For example, because the plasma is created from air that naturally diffuses around food – think a punnet of strawberries with space around each fruit – the sterilising effects reach to the bottom of the box, unlike UV light treatment which has shadowing problems.

The benefits of plasmas don’t end there. The whole operation takes place at room temperature (the ‘cold’ part of the ‘cold plasma’ equation) negating the need for high-cost, high-energy systems. “The big advantage is that it’s consumables free and uses the air around it. We just provide a tiny amount of electricity, tens of watts, which is less than a lightbulb uses,” Walsh explains.

University of Liverpool researchers working with industry

Walsh is currently testing a pilot system in industrial settings, working with collaborators including supermarket Sainsbury’s and their three leading suppliers of fruit and vegetables, fine tuning the device so food can be treated on a conveyor in less than a second. Utilising the flexible Liverpool Model for working with industry, the final device should cost under £10,000 and can be retrofitted to existing machines. This compatibility with existing processing infrastructure vastly increases its commercial and export potential, making it attainable for low and middle-income countries.

The three-year Innovate UK-funded project has a total grant value of £350,000, with approximately half the funds coming from the UK Government, and half from industry. It forms part of the multi-partner £11 million ‘Improving food chain efficiency’ programme.

To find out more about this project contact James Walsh

The relevant research publications are available here

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