Journal of Food Processing & Technology

Abstract

Inactivation of Francisella tularensis Utah-112 on Food and Food Contact Surfaces by Ultraviolet Light

Christopher H. Sommers, O. Joseph Scullen, George C. Paoli, and Saumya Bhaduri

Francisella tularensis is the causative agent of tularemia, a plague-like illness that affects animals and humans, and has caused large illness pandemics in the last century. It has also been used as a biological warfare agent, and tularemia can be contracted through consumption of contaminated food and water. In this study the use of a U.S. Food and Drug Administration approved technology, 254 nm ultraviolet light (UV-C), to inactivate F. tularensis Utah-112 (a rodent pathogen) on food and food contact surfaces was investigated. The D10 value, the UV-C dose needed to inactivate one log of microorganism, was approximately 0.71 mJ/cm2 on agar plates using a low UV-C intensity of 100μW/cm2/s. When a commercial UV-C conveyor was used (5 mW/cm2/s) 0.5 J/cm2 inactivated >7 log CFU of F. tularensis Utah 121 on agar plates. At 0.5 J/cm2 UV-C inactivated >4 log CFU of Utah-112 in beef, chicken, catfish, frankfurter, and bratwurst exudates inoculated onto stainless steel coupons, and >7 log CFU was eliminated at 1 J/cm2 UV-C. Similar results were obtained when the exudates were inoculated onto high density polypropylene. Approximately 0.5 log CFU was inactivated on chicken breast, beef steak, and catfish fillets, and approximately 1.9 log CFU on frankfurters and bratwurst at a UV-C dose of 1 J/cm2. These results indicate routine use of UV-C during food processing would provide workers and consumers some protection against F. tularensis.