A Norwegian fish processing plant turned to Evoqua partner Naustor Technology to eliminate a persistent listeria problem in production.
Trond Storebø at Naustor has been installing Evoqua’s ozone generators on board fishing vessels for the past fifteen years, and knows the industry’s requirements well.
He supplied them with one of Evoqua’s new PC Series ozone disinfection systems. The PC Series is a trolley mounted unit that can provide ozonated water instantaneously anywhere in the food processing factory. The ozone is produced inside the on board generator from ambient air and electricity, making it capable of fully autonomous operation. The all stainless-steel PC Series incorporates an on-board oil-free air compressor, pump and off-gas destructor, making it completely safe for operators, with the capability to adjust the ozone output to provide greater flexibility and a broader range of application uses.
“Before the customer started using the mobile ozone system, they used chemicals for sanitisation, but could not get rid of the bacteria,” Trond Storebø said.
“Since the introduction of ozone, they have not detected listeria at all within the plant, process machinery or the final product.”
He explained that ozone acts more quickly than chlorine-based chemicals – at a concentration of 2,5 mg/l disinfection is almost instantaneous – and it destroys the extracellular polysaccharides that form adherent biofilms.
There are instances of food processing facilities and smoke houses having been shut down by government agencies due to listeria-infected products, and listeriosis is serious infection caused by eating contaminated food which can be fatal for those with weakened immune systems.
The causal agent is Listeria monocytogenes and the food industry relies on sodium hypochlorite (bleach), peracetic acid and other chemicals to ensure that food-contact surfaces and equipment are disinfected.
There is increasing evidence of the emergence of chemical-resistant strains of many bacteria, including Listeria, Aeromonas and Bacillus cereus.
Alternative biocides are available but most are less easy to handle and may raise health and safety concerns.
The alternative that has been around for many years but, until recently, has been little used in the food processing industry is ozone, a powerful disinfectant and an environmentally sustainable alternative that leaves no chemical by-products.
“The use of ozone has made the products safer, enhanced the shelf-life for the fresh produce and protects the company’s brand,” Trond Storebø added.
“Employees also noticed reduced smells in the factory because ozone also removes the slippery fish-film from the floor. This has provided a better working environment for everyone, and in addition the use of ozone is a practical application since it is produced safely on site and allows the company the possibility to produce their own disinfectant.”