Scientists trial charged-water irrigation system to boost food safety
The research could also help keep irrigation pipes clean and give growers the ability to irrigate with water previously deemed too poor to be used on vegetables.
Electrolysed oxidising water techniques (EO) are already used to sanitise water used on produce post-harvest to kill bacteria and extend shelf life, but using them pre-harvest on a large scale is a new concept.
The water is sanitised when it passes electrodes, which convert chloride salts in the water into chlorine.
The three-year project began in June with growers recruited in South Australia and New South Wales for on-farm trials.
University of South Australia scientist Enzo Lombi, who is behind the project, said the technology was scalable and could be used to sanitise thousands of litres of water an hour—enough to service entire farms.
He said the technology would be most effective at treating leafy crops that are consumed fresh, such as lettuce, spinach and parsley.
“The technology basically converts the chloride in the water into chlorine, which is a very strong oxidising agent that kills off the micro-organisms,” Professor Lombi said.
The research will mainly look at human pathogens like salmonella and ecoli, but will also look out for any positive effects in eliminating crop diseases.
“With more and more demand for food safety now is the right time to test it out and it should be cheap enough so it is affordable for farmers,” he said.
The sanitised water would also help clean biofilms from irrigation pipes and allow farmers to access water sources not previously deemed suitable for irrigation because of high microbial content.
Prof. Lombi believes the certified-organic EO water could play a significant role in organic farming.
“I’m sure there will also be some unexpected things we find along the way, and the follow-up might be that we find that it is also useful as an alternative to pesticides in organic farming,” Prof Lombi said.
“We have a pretty heavy laboratory component where we can do some really detailed studies on whether it works for example to reduce the risk of pathogens growing on crops. In the second and third year we will continue with the lab studies while we also have on-farm trials at a least two locations.”
The vegetable industry is one of the Australia’s biggest horticultural segments with an annual production of around 3.5m tonnes and a value of $A8.7bn (US$6.9bn).
John Lloyd, chief executive of Hort Innovation, the grower-owned R&D company which is backing the study, said the use of EO water as an irrigation treatment would complement Australia’s famously strict food safety standards.
“Growers want to build on these standards even further by investing in research to stamp out product recalls and maximise consumer confidence. An additional layer of food safety protection can only help achieve that,” he said.