Evaluation of Far Ultraviolet-C Light for Decontamination of Organisms in Whole Milk and Chicken Manure

Background: The dissemination of highly pathogenic avian influenza (HPAI) A(H5N1) in US poultry and dairy cows poses a public health threat. Farm workers caring for infected animals are at risk to acquire infections due to exposure to contaminated milk or poultry feces and secretions. Far ultraviol...

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Bibliographic Details
Main Authors: Samir Memic, Jennifer Cadnum, Curtis Donskey
Format: Article
Language:English
Published: Case Western Reserve University 2025-05-01
Series:Pathogens and Immunity
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Online Access:https://www.paijournal.com/index.php/paijournal/article/view/801
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Summary:Background: The dissemination of highly pathogenic avian influenza (HPAI) A(H5N1) in US poultry and dairy cows poses a public health threat. Farm workers caring for infected animals are at risk to acquire infections due to exposure to contaminated milk or poultry feces and secretions. Far ultraviolet-C (UV-C) light could provide continuous decontamination of surfaces and air in agricultural settings, but efficacy against organisms in whole milk or chicken manure is unclear. Methods: We examined the efficacy of far UV-C light against bacteriophage MS2 and methicillin-resistant Staphylococcus aureus (MRSA) in phosphate-buffered saline (PBS), 5% fetal calf serum, whole milk, or 5%, 10%, and 25% chicken manure, both in liquid suspension and dried on surfaces. We also compared the efficacy of 300 mJ/cm2 doses of far UV-C and 254-nm UV-C light against the test organisms in liquid droplets or droplets dried on surfaces.  Results: For both test organisms, far UV-C achieved significantly smaller log10 reductions in whole milk and in chicken manure suspensions than in PBS or 5% fetal calf serum, both in liquid suspension and when dried on surfaces (P<0.0001). In whole milk, average reductions of both organisms with all doses were <1.2 log10 in liquid suspensions and <2.4 log10 when dried on surfaces. We found 254-nm UV-C was significantly more effective in reducing MRSA and MS2 dried on surfaces in whole milk or in 10% chicken manure (P<0.02) but not in liquid droplets (P>0.05) except 5% chicken manure (P<0.001).  Conclusions: Our results suggest that in the absence of prior cleaning and disinfection far UV-C and 254-nm UV-C light technologies may have limited efficacy as an adjunctive method to reduce the risk for transmission of HPAI from surfaces in high-risk settings on farms.
ISSN:2469-2964