Submitted to: Food Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/2015
Publication Date: 2/21/2015
Citation: Sommers, C.H., Sheen, S. 2015. Inactivation of avirulent Yersinia pestis on food and food contact surfaces by ultraviolet light and freezing. Food Microbiology. DOI: 10.1016/j.fm.2015.02.008.
Interpretive Summary: Yersinia pestis is the causative agent of plague, and can occasionally cause naso-pharangeal or gastrointestinal illness in people through consumption of contaminated meat. Ultraviolet light (UV-C: 254 nm), a green and sustainable chemical free technology, is now used in the health care industry to kill microorganisms and is now being adopted by the food processing industry for the same purpose. In this study we investigated the ability of UV-C to kill Y. pestis suspended in drip from chicken, beef, and catfish fillets placed on stainless steel and plastics commonly used by the food processing industry in conveyors and other food processing equipment. We found that a low UV-C dose of 0.5 J/cm2 killed 99.99% of the Y. pestis in the exudates on the stainless steel and plastics. In addition, the UV-C was able to kill > 90% of the Y. pestis on beef steaks, boneless and skinless chicken breasts, and catfish fillets. Freezing foods also killed 90% of the Y. pestis. These results indicate that routine use of UV-C during food processing would provide workers and consumers some protection against Y. pestis. The results of this study will allow regulatory agencies and the radiation and food processing industries to conduct risk analysis and provide safer meat to consumers. Consumers, especially those who are immuno-compromised (eg. cancer patients, diabetics, and the HIV/AIDS population) will benefit from having more information about foods treated with alternative processes such as ultraviolet light.
Technical Abstract: Yersinia pestis, the causative agent of plague, can occasionally be contracted as a naso-pharangeal or gastrointestinal illness through consumption of contaminated meat. In this study, the use of 254 nm ultraviolet light (UV-C) to inactivate a multi-isolate cocktail of avirulent Y. pestis on food and food contact surfaces was investigated. When a commercial UV-C conveyor was used (5 mW/cm2/s) 0.5 J/cm2 inactivated >7 log of the Y. pestis cocktail on agar plates. At 0.5 J/cm2, UV-C inactivated ca. 4 log of Y. pestis in beef, chicken, and catfish, exudates inoculated onto high density polypropylene or polyethylene, and stainless steel coupons, and > 6 log was eliminated at 1 J/cm2. Approximately 1 log was inactivated on chicken breast, beef steak, and catfish fillet surfaces at a UV-C dose of 1 J/cm2. UV-C treatment prior to freezing of the foods did not increase the inactivation of Y. pestis over freezing alone. These results indicate that routine use of UV-C during food processing would provide workers and consumers some protection against Y. pestis.