Title: UV-C Inactivation of Francisella tularensis Utah-112 on agar surfaces, stainless steel, and foods Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 1, 2010
Publication Date: July 18, 2010
Citation: Sommers, C., Paoli, G., 2010. UV-C Inactivation of Francisella tularensis Utah-112 on agar surfaces, stainless steel, and foods [abstract]. Institute of Food Technologists Annual Meeting. Chicago, IL. p.1. Technical Abstract: Francisella tularensis has been identified as a microorganism of concern in the field of food security. There is currently very little information on the ability to inactivate F. tularensis on foods using non-thermal processing technologies. The ability of ultraviolet light (UV-C) to inactivate F. tularensis Utah-112 (a mouse pathogen) on the surfaces of thioglycollate agar plates, stainless steel, frankfurters, bratwurst, vegetable frankfurters, and plum tomatoes was investigated. F. tularensis Utah-112 was grown to stationary phase in fluid thioglycollate medium (37C) and surface inoculated onto the various surfaces, treated with UV-C light (5 mW/cm2/s for foods and 100 uW/cm2/s for agar and stainless steel), rinsed from the product surfaces using phosphate buffer, and then incubated on thioglycollate agar plates for 3 days (37C). A 5.7 (0.61) log reduction of the pathogen on thioglycollate agar plates was obtained with a UV-C dose of 4 mJ/cm2 while a 3.5 (0.48) log reduction was obtained on stainless steel surfaces. A UV-C dose of 1 J/cm2 inactivated 2.1(0.06), 1.42(0.27), 2.1 (0.13), and 3.6 (0.11) log of F. tularensis Utah-112 on frankfurters, bratwurst, vegetable frankfurters, and plum tomatoes, respectively. These log reductions for a F. tularensis isolate, which may be the first reported in the scientific literature, are similar to those obtained on agar surfaces, stainless steel, and similar foods for food-borne pathogens including Salmonella spp. Listeria spp., and Staphylococcus aureus.