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Supercharged air electrifies the fight against microbial contamination

Technology & Data

cold plasma fruit treatment

Dr Sukhvinder Pal (SP) Singh, a Food Safety Scientist at NSW DPI, will present as part of APAL’s upcoming webinar series on Thursday 14 May about a highly promising new method of treating apples to minimise microbial food safety risks. The technology has the potential to greatly improve food safety and reduce postharvest losses due to decay.

What is it?

Supercharged air (otherwise known as “cold plasma”) is created by applying an electric current to normal air or a gas. Ionising the air produces highly reactive free radicals found to have broadspectrum antimicrobial activity capable of killing bacteria, viruses and moulds.

How does it work?

“Imagine an automatic carwash”, says SP. “The car moves through the carwash and is showered on all sides by soap and water. Supercharged air treatment is just like this – the fruit will move through a tunnel where it will be showered with supercharged air from all directions.”

The free radicals created by the supercharged air only live for milli or nanoseconds but in that time they attack and damage the DNA and cell membrane of pathogens living on the food surface. SP notes that this is a surface treatment only, and supercharged air is ineffective in attacking any problems lurking below the surface of the fruit.

What are the benefits?

The two main methods of treatment currently in use are chemical treatment and heat. Chemical treatments such as chlorine are becoming increasingly unpopular with consumers, with a global push to move away from chemicals that are not environmentally friendly, and customer concern about chemical residue on foods.

“Heat treatment that can be tolerated by most fresh produce is not good enough to kill Salmonella, E.coli and other foodborne pathogens”, says SP. “You would have to raise the heat and duration to levels that would damage the heat-sensitive fruit.”

Supercharged air treatment:

  • leaves zero chemical residue
  • can operate at ambient temperature
  • takes between 30 seconds to two minutes (depending on the pathogens targeted)
  • can be retrofitted to existing systems and is suitable for in-line processes
  • has broadspectrum antimicrobial activity including killing dangerous bugs such as salmonella and listeria
  • can be used alone or in combination with another treatment
  • is an energy efficient decontamination technology
  • improves post-harvest decay control.

When will supercharged air treatments be available?

SP’s team has finished the experimental stage and is now scaling up with a commercial partner. The team expects to demonstrate the new decontamination tool to industry in 2020 and work with growers and packers to continuously improve the technology.

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