Control of Listeria and Salmonella in Food Processing: The Role of Ozone Technology

Control of Listeria and Salmonella in Food Processing: The Role of Ozone Technology

Listeria monocytogenes and Salmonella spp. remain among the most critical foodborne pathogens worldwide. In fresh and dried fruit and vegetable processing, insufficient control of these microorganisms can lead to product recalls, export rejections, regulatory non-compliance, and serious public health risks.

This article examines the behavior of Listeria and Salmonella throughout food processing environments, the limitations of conventional sanitation methods, and how OCS OZON ozone technology provides an effective, residue-free solution from a process engineering perspective.

Why Are Listeria and Salmonella Such Critical Risks?

Listeria monocytogenes

  • Capable of growth at refrigeration temperatures

  • Highly persistent in moist processing environments

  • Strong biofilm-forming ability on equipment and surfaces

  • Major risk for ready-to-eat (RTE) fresh produce

Salmonella spp.

  • Can survive for long periods in low–water activity foods

  • Highly resistant in dried fruits and dry processing environments

  • Easily spread through cross-contamination

  • Frequently associated with fruit, vegetable, and nut recalls

These characteristics make both pathogens hazards that must be controlled throughout the entire processing chain, not only in the final product.

Limitations of Conventional Disinfection Methods

Traditional chemical disinfectants (e.g., chlorine-based systems) can reduce microbial loads but often show limitations such as:

  • Risk of chemical residues

  • Reduced effectiveness against biofilms

  • Limited impact in cold storage and air sanitation

  • Increased environmental and wastewater burden

As a result, conventional methods alone are often insufficient for robust Listeria and Salmonella control.

Why Is Ozone Technology Effective?

Ozone (O₃) is a powerful oxidizing agent with a high oxidation potential and no chemical residue.
OCS OZON systems generate ozone in a controlled and stable manner, making it suitable for food-grade applications.

Mechanisms of Action Against Listeria and Salmonella

  • Lipid peroxidation of cell membranes

  • Oxidative damage to proteins and key enzymes

  • Disruption of DNA and RNA integrity

  • Breakdown of biofilm structures

This multi-target mode of action enables ozone to deliver rapid, broad-spectrum microbial inactivation.

Ozone Applications in Fresh Fruit and Vegetable Processing

In fresh produce operations, ozone is most commonly applied as aqueous ozone.

Typical process parameters using OCS OZON systems:

  • Ozone concentration: 1–3 mg/L

  • ORP: 700–850 mV

  • Contact time: 2–5 minutes

  • Temperature: 2–8 °C

Under these conditions:

  • 1–3 log reductions of Listeria and Salmonella are commonly achieved

  • Wash water hygiene is continuously maintained

  • Cross-contamination risks are significantly reduced

Pathogen Control in Dried Fruits and Storage Areas

Salmonella is particularly problematic in dried products due to its ability to survive in low-moisture environments. Therefore, control strategies must address not only the product surface but also storage air and processing surfaces.

With OCS OZON gaseous ozone applications:

  • Airborne pathogen loads are reduced

  • Surface biofilms are suppressed

  • Recontamination risks during storage are minimized

This approach is also effective in limiting Listeria persistence in cold storage environments.

Ozone as Part of HACCP and CCP Management

Listeria and Salmonella control often requires designation as Critical Control Points (CCPs).

OCS OZON systems enable continuous monitoring and control of:

  • Ozone concentration

  • ORP levels

  • Contact time

  • Temperature and relative humidity

This transforms ozone from a simple sanitizer into an active and verifiable process control tool.

Conclusion: A Process-Based Strategy Against Listeria and Salmonella

Effective control of Listeria and Salmonella requires a holistic approach covering:

  • Washing lines

  • Processing equipment

  • Storage areas

  • Air and surface sanitation

OCS OZON technology provides:

  • Residue-free disinfection

  • Chemical-free operation

  • Industrial-scale reliability

  • Full compatibility with food engineering principles

As food safety regulations continue to tighten globally, proper process design combined with the right ozone technology offers a decisive advantage in managing Listeria and Salmonella risks.