Minimising your food safety risk: 12 months on from the Rock Melon Listeria outbreak

12 months on from the Rock Melon Listeria outbreak in NSW that claimed seven lives, we reflect on the importance of implementing your own sanitising controls for fresh produce to minimise your food safety risk and how eWater Sanitiser can be used in the process.

The investigation into this listeria outbreak was released in October 2018, and concluded the contaminated fruit came from a single farm in New South Wales, and the outbreak was largely caused by the weather. The report said the farm's hygiene and sanitary procedures were "on par with or better than most other rockmelon-growing operations across Australia".


Despite this, heavy rains in December and dust storms that followed covered the farm's paddocks in dust, and "significantly increased" the amount of listeria on the fruit. In addition, inspections by the NSW Food Authority found there was also an opportunity for the introduction of Listeria after washing through contact with surfaces or equipment that may have had traces of Listeria monocytogenes. This includes dust blown from fans used to dry the fruit after washing, and from porous material on packing tables that was not able to be effectively cleaned at the time.

Listeria is a common bacteria found in most environments, but it can be dangerous for people with poor immune systems, such as small children and the elderly. Rockmelons on the farm were washed in a chlorine solution and scrubbed prior to packing. "The wash water was not recirculated, sanitiser was constantly monitored and applied through an auto-dosing system, and all water coming into the facility was treated and considered potable," the report said.

What is Listeriosis?

1. Listeriosis is a serious and sometimes fatal bacterial infection.
2. Symptoms can include fever, headaches, cramps, aches and pains, nausea and diarrhea.
3. It can be fatal in newborns, elderly people and people with a weakened immune system.

Mitigating Your Food Safety Risk

It is clear from this unfortunate case that while the proper sanitising procedures were in place, mitigating the risk of contamination cannot solely be the responsibility of the producer. In fact, despite supplier accreditation’s and audit results, to mitigate your own risk you need take the step on ensuring your food safety program includes a control point for effectively removing bacteria such as listeria present on all fresh produce.

washing rockmelon.jpg

As listeria can live on the skin of the rock melon, contamination can occur at any point from preparation to sale, so it is imperative that controls are implemented from the beginning of the production cycle to the end. By having this step as a control point in your food safety program you are minimising the risk to your customers.

Using eWater Sanitiser to kill Listeria

At the time of the outbreak, eWater Systems released a special paper to highlight the effectiveness of Electrolysed Water at killing Listeria and other common food bacteria. We have taken key points from this paper to highlight the role eWater Sanitiser can play in mitigating the risks of food contamination.

eWater Sanitiser with fresh produce

Washing Fresh Produce with Electrolyzed Water

A study published by the Department of Food Science and Technology at the University of Georgia determined that electrolysed water (eWater) achieved complete inactivation of Escherichia coli (Ecoli) and Listeria.

Further verification of eWater came in 2017 when the Department of Food Sciences at Rutgers University found soaking lettuce heads in eWater sanitiser significantly reduced levels of Salmonella, E. coli and Listeria compared to tap water and acid sanitisers.

The NSW Vulnerable Persons Food Safety Scheme Consultative Committee (VPFSSCC) have even recommended that eWater be used as an alternative sanitiser, especially in environments where listeria is of concern.


eWater Sanitiser on Stainless Steel Surfaces

Spraying Stainless Steel with Electrolysed Water

A separate study by the Department of Food Science and Technology, University of Georgia investigated the ability of eWater to inactivate listeria on stainless steel surfaces, such as those used in food preparation areas. Researchers exposed stainless steel coupons to listeria for several hours then submerging the coupons in eWater for periods ranging from 10 to 300 seconds.

“Results obtained from this study demonstrated that 300s Electrolysed Water treatment on stainless steel surfaces significantly reduced the number of biofilm-forming bacteria from 1.9 x 10" CFUB2.5 cm2 to below detection levels. Electrolysed Water treatment is an effective means of inactivating biofilm forming bacteria on equipment surface during cleaning.”

To read the complete paper see this link

What this meant for our customers

For many of our customers, the integration of eWater Sanitiser within their food safety program is central to managing and mitigating the risk in their operations from potential outbreaks.


A primary benefit of the eWater Hygiene System is that it is an on-site generator of solution. This means that it can be designed into the kitchen environment at the correct operational points. The result is an efficient and effective supply of sanitising solution that integrates straight into the food prep processes of the kitchen.

With eWater Hygiene Systems being approved by HACCP as a producer of food safe sanitising solution, operators can be confident that they are using a system that supports their food safety program without placing additional operational burden on the team.

For further information regarding eWater Hygiene Systems or how our solutions can be effectively integrated into your food safety plan please contact our expert team.