The researchers used a prototype retractable device to generate plasma, which is created by heating a gas to form positive and negative ions.
This separates the bonds between oxygen molecules within the packaging to create ozone gas – already a well-known germicide. This then works on the food surface to kill microbes there.
Having been created in this way, the ozone molecules naturally revert back to oxygen molecules after a couple of hours. This is more than enough time to destroy any pathogen, fungus or mould, which would otherwise pose a health hazard or impair the taste of the food.
Can extend product shelf life
The developers, Dr Declan Diver and Hugh Potts of the University’s School of Physics and Astronomy, claim the technology can extend product shelf life by at least a day, reducing waste.
The system does not need substantial amounts of oxygen in packs to work, Diver told FoodProductionDaily.com. Trials had been conducted on packs containing just 5% oxygen, he said.
However, it still requires a small amount of oxygen to work, so some oxidative damage of food would have to be accounted for, he added. "It will produce oxidative damage in high fat foods, so there's a taste issue there."
Beverages
And because the application applied only to food surfaces, this called into question its use for beverages, he said. "It's not immediately obvious how this would apply to liquids - once the surface gets sloshed around, you would have to deal with microbial contamination again."
The gadget is being brought to market by a spin-off company called Anacail, which means ‘shield’, ‘protect’ or ‘preserve’ in Gaelic, which is seeking partners to commercialise it.
The firm was set up in January 2011 and recently raised £750,000 of start-up funding from IP Group, which specialises in commercialising technologies, and the Scottish Investment Bank, a division of Scottish Enterprise.
‘Doesn’t require chemical additives’
“We’re very excited about the applications of our product,” said Anacail chief executive Dr Ian Muirhead. “It’s safe and easy to use, doesn’t require any change in current packaging of food products to be effective, and it doesn’t require any chemical additives – the sterilisation effect comes directly from oxygen via our plasma head.
“Although ozone can be harmful to humans, it has a very limited lifespan before it returns to oxygen and it doesn’t leave behind any dangerous residues so it’s perfectly safe to use in food decontamination. It’s a very effective way to destroy or inhibit the growth of bacteria and viruses.
‘Seeking development partners’
“We’re currently seeking development partners to scale our product into full manufacture. Although we’re initially concentrating on offering Anacail products to the food industry, the process could be equally useful in for the sterilisation of medical and dental equipment and perhaps even for use in the home.”
The efficacy of Anacail’s prototype has been proven at UK laboratories including Campden BRI in Gloucestershire, England.
Tests have shown an increase in shelf-life for products including bread and muffins and a significant reduction of many pathogens in poultry including campylobacter, pseudomonas, and E.coli, claims Anacail.
And while ozone can be toxic for humans, the company stresses that it quickly disperses in packaging long before products end up on shelves and leaves no harmful residues.