In June 2024, Atria - a leading Nordic food company - tested the Spectral Blue SALO XL blue light disinfection device against Listeria monocytogenes in a biosafety cabinet used for handling control strains. The multi-wavelength, high-intensity (MWHI) blue light emitted by the device eliminated 100% of the Listeria colonies.
Listeria monocytogenes is one of the most challenging pathogens for the food industry due to its ability to survive even in cold storage. This bacterium is also notorious for forming biofilms that are difficult to eliminate. Foods contaminated with L. monocytogenes pose a serious health risk for consumers. Consequently, the food industry invests heavily in contamination control measures. The most innovative food processing companies are continuously seeking new methods to prevent L. monocytogenes growth within their facilities.
To evaluate the Spectral Blue device, Atria installed it in one of their laboratory's biosafety cabinets. The testing environment and procedure mirrored their routine food quality analysis practices, meaning that strong performance in the test would likely translate to similar results in real-world use.
The Listeria monocytogenes samples were prepared in appropriate dilution series and applied to metal discs. Nine discs were evenly distributed within the biosafety cabinet under the blue light device. An additional sample was placed in a separate cabinet under similar conditions but shielded from blue light exposure. The nine discs were then treated with MWHI blue light for 8 hours (from 9 pm to 5 am). Finally, all 10 samples were analyzed according to ISO 11290-2:2017 to determine the number of viable L. monocytogenes colonies
After the treatment, the nine samples exposed to MWHI blue light were all completely inactivated, with a viable CFU count of zero. The dark control showed no reduction in viable CFU count.
The results demonstrate that Spectral Blue is highly effective against the most challenging food-borne microbes and can be utilized in biosafety cabinets to prevent cross-contamination and reduce the risk of infection to staff.
- Download the complete test report under Science > Laboratory test results.