Understanding Listeria: A Critical Threat to Food Safety

Listeria is a major concern for food processing companies because it thrives in cool, moist environments, making food processing plants particularly vulnerable. It can survive refrigeration and even freezing temperatures, which means it can easily contaminate ready-to-eat products, dairy, meat, and seafood. Once Listeria enters the production environment, it can be difficult to eliminate, leading to recalls, business shutdowns, and serious public health risks.

This article covers key things to know about Listeria and key considerations in controlling Listeria contamination in food production environments. We also highlight why blue light is an ideal solution for eradicating Listeria contamination.

What is Listeria?

Listeria monocytogenes (Lm) is a gram-positive, non-spore-forming, motile, facultatively anaerobic, rod-shaped bacterium commonly found in soil, water, and some animals.
Invasive infection by Lm causes the disease listeriosis.
The manifestations of listeriosis include gastro-intestinal infection, sepsis, meningitis corneal ulcer, pneumonia, myocarditis, and infections in pregnant women, which may result in spontaneous abortion or stillbirth. Listeriosis poses a significant health risk also to newborns, the elderly, and those with weakened immune systems.
Lm is quite hardy and resists the deleterious effects of freezing, drying, and heat remarkably well for a bacterium that does not form spores.

How Does Listeria Affect Food Processing?

Listeria monocytogenes (Lm) is one of the major concerns for environmental contamination of ready-to-eat foods due to its widespread distribution and ability to survive well in the environment of packing- and processing-related surfaces and equipment.
Lm has been associated with such foods as raw milk, pasteurized fluid milk, cheeses (particularly soft-ripened varieties), hard-boiled eggs, ice cream, raw vegetables, fermented raw-meat sausages, raw and cooked poultry, raw meats (of all types), and raw and smoked fish and other seafood.
Lm has the ability to grow at temperatures as low as 0 °C which permits exponential multiplication in refrigerated foods.
Lm tends to form biofilms very rapidly (24-48 hrs). The biofilm production of Lm is presumed to be one of the ways that confer its increased resistance and persistence in different stages of food processing. Biofilm formation enhances Lm’s resilience against adverse conditions such as dryness, disinfectants, antibiotics, rendering complete eradication challenging.

Key Industries at Risk: Ready-to-eat meals, dairy products, meat processing, and seafood.
Impact on Food Processing Companies: Potential product recalls, regulatory penalties, damage to brand reputation, and costly shutdowns for cleaning and sanitizing production lines.

Considerations in cleaning and disinfecting Listeria in food industry with traditional methods

Cleaning with high-pressure water is not recommended, as it can disperse the Listeria contamination everywhere in aerosol form. Cleaning with low-pressure water is better suited.
Heat: often not possible to use for practical reasons.
Alcohol 70%: Ethanol cannot be used extensively for health and safety reasons.
Quaternary ammonium chlorides: Resistance buildup or QAC transfer to food products.
Enzymatic cleaning agents are available on the market and could be an option to regular alkaline foams to remove residual soil, but they are still not commonly used.
It is recommended to rotate between alkaline and acidic disinfectants, but surfaces must be cleaned of chemical residues in between so the different chemicals do not affect each other.
When suspecting the presence of biofilms, it is not enough to do extra cleaning a few times per year. The thorough cleaning should be done daily.
Lm can easily spread from one part of the facility to others for example on the shoes of the operators. Therefore it is important to do frequent sampling in all areas and extend the hygiene practices to cover all key areas.
Only thorough and continuous attention to good hygiene will eradicate Listeria contamination.

Why Spectral Blue? The Innovative Automatic and Continuous Solution for Listeria Control

Advanced Protection Against Listeria
Spectral Blue offers a groundbreaking approach to controlling Listeria contamination. It provides an advanced, touch-free, non-toxic, and eco-friendly solution that helps food processors effectively combat Listeria bacteria without harsh chemicals or damaging the environment.

Key Benefits of Spectral Blue

Non-toxic & Chemical-Free: Spectral Blue uses light wavelengths that are safe for humans and the environment, making it ideal for food processing facilities where traditional chemicals might pose risks or leave residues.
Effective in Challenging Environments: Blue light technology is effective even in cool and moist conditions where Listeria typically thrives, offering consistent protection without the need for liquid chemicals.
Continuous Protection: When integrated into your facility’s operations, Spectral Blue provides ongoing microbial control, reducing the risk of Listeria contamination over time without the need for constant reapplication.
Compliance with Food Safety Standards: Spectral Blue helps companies meet FDA and international food safety regulations, offering a modern solution that supports industry-leading hygiene standards.

How Spectral Blue Works

Step 1: Installation: Spectral Blue MWHI blue light devices can be deployed in food processing environments to illuminate surfaces, conveyor belts, food storage units, or processing lines.
- Because Spectral Blue is safe for people, it can be deployed also in areas where people are working. The high-intensity blue light can be distracting though, so typically a presence sensor is included to turn the lights off when people are close.
Step 2: Immediate Bacterial Control: Once operational, the blue light immediately begins to deactivate harmful bacteria by disrupting their cellular processes, preventing their ability to multiply. It works also through biofilm.
Step 3: Continuous Operation: With no need for manual reapplication, Spectral Blue ensures constant, uninterrupted protection against bacterial threats, safeguarding your facility and products from contamination.

Success Stories: Spectral Blue in Action

Many food processors using Spectral Blue have seen remarkable improvements in hygiene and safety standards. Please see our case studies to see how Spectral Blue has been used in food processing environments.

With reduced Listeria contamination and fewer costly recalls, food companies are able to protect both their brand and customers.

Protect Your Brand and Customers Today

Don’t let Listeria compromise your food processing operation. With Spectral Blue’s advanced blue light technology, you can safeguard your products, maintain compliance, and ensure the highest standards of food safety. Contact us to learn more about how Spectral Blue can bring innovative protection to your facility.