Zapping fruit with plasma beams could extend shelf life

03 Mar 2011

Mouldy fresh fruit could become a thing of the past thanks to cold plasma beams that extend its shelf life by up to five days, according to an academic heading a new study into the technology.

Strawberry fields mould-free forever? Cold plasma technology in action

Millions of tonnes of soft fruit – sold in both its native state and added to various food products – are wasted each year, after mould develops on fragile produce that deteriorates rapidly after picking.

But a new six-month collaborative study between the universities of Nottingham and Loughborough and fruit association Berry World, is looking at how cold plasma technology could help address the problem, potentially revolutionising supply chains and effecting massive cost savings for food manufacturers, retailers and consumers.

Technology drawn from medical science

Doctors already use cold plasma technology to clean bacteria from wounds, and the academic team made the chance discovery that it could be applied to food when looking at how the tiny controllable plasma beams (which are similar to lightning) can be used to kill micro-organisms and sterilise surfaces.

Dr Cath Rees, from University of Nottingham School of Biosciences said that promising experiments thus far showed “fabulous” results, with fresh fruit shelf life extended by up to five days in best-case scenarios.

Rees said: “Soft fruit is notoriously difficult to keep ‘fur free’ for long, as it bruises easily when handled and becomes contaminated. Cold plasma technology would present a way of eradicating moulds early in the packing process.”

Uneven results thus far

However, she said the team’s early results had been uneven: “A lot depends upon the state of the fruit, humidity levels, temperature and storage issues that affect the food surface. All these issues affect the optimal application of the technology. Our data is mainly observational right now, and we need to collect more novel food processing and safety data before this technology goes mainstream, and prove that it causes no changes in fruit or leaves residues.”

Rees added that the cross-institutional team will have assessed relevant parameters within the next six months to a year. It will then have a better idea about how the technology works, and will be able to assess when it could begin to be used within food production after viable machines are developed.

“We’re working on a very small scale right now, and there is interest in the technology within other fields in regard to scaling-up the technology on a mass scale: Loughborough is taking care of the engineering side [within the current project]."

The study is being funded by a grant from the East Midlands Food and Drink iNet, which is based in Nottingham.

Source: University of Nottingham School of Biosciences