Title: Ultraviolet Light (254 nm) Inactivation of Listeria monocytogenes on frankfurters that contain potassium lactate and sodium diacetate Authors
Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 2, 2008
Publication Date: March 1, 2009
Citation: Sommers, C.H., Cooke, P.H., Fan, X., Sites, J.E. 2009. Ultraviolet Light (254 nm) Inactivation of Listeria monocytogenes on frankfurters that contain potassium lactate and sodium diacetate. Journal of Food Science. 74(3):M114-M119. Interpretive Summary: Listeria monocytogenes, a foodborne pathogen, is an occasional contaminant on frankfurters. The levels of L. monocytogenes on frankfurters are very low, typically less than one cell of the pathogen per gram of meat. A technology that inactivates even modest numbers of L. monocytogenes could therefore reduce the numbers of recalls and foodborne illness outbreaks caused by L. monocytogenes. Ultraviolet light is an FDA approved technology for decontaminating the surfaces of foods. Potassium lactate and sodium diacetate are FDA approved antimicrobial compounds that are used in frankfurters to prevent the growth of L. monocytogenes during refrigerated storage. In this study we found that the use of ultraviolet light, when used in combination with potassium lactate and sodium diacetate, resulted in greater than a 99 percent reduction in the levels of L. monocytogenes on the surfaces of frankfurters following 2 months refrigerated storage. In addition ultraviolet light had no effect of frankfurter quality. This work will assist meat processors provide safer ready-to-eat meat products to consumers.
Technical Abstract: Listeria monocytogenes, a psychrotrophic food-borne pathogen, is an occasional post-process contaminant on ready-to-eat meat (RTE) products including frankfurters. Potassium lactate (PL) and sodium diacetate (SDA) are FDA approved antimicrobials that inhibit the growth of L. monocytogenes when incorporated into the formulation of fine emulsion sausage. Ultraviolet C light (UVC) is an FDA approved technology for the decontamination of food surfaces. In this study the ability of UVC to inactivate L. monocytogenes on frankfurters that contained PL and SDA, either before or after packaging, was investigated. UVC irradiation of frankfurters that were surface-inoculated with L. monocytogenes resulted in a 1.31, 1.49 and 1.93 log reduction at doses of 1, 2, and 4 J/cm2, respectively. UVC treatment had no effect on frankfurter color or texture at UVC doses up to 4 J/cm2. Frankfurter meat treated with UVC doses up to 16 J/cm2 did not increase mutagenesis in the Ames Assay, either with or without exogenous metabolic activation. UVC treatment of single layer frankfurter packs at a dose of 1 J/cm2 per side resulted in a 0.97(0.14) log reduction of L. monocytogenes. Following 8 weeks of refrigerated storage L. monocytogenes levels decreased by only 0.65 log in non-UVC-treated frankfurter packs versus 2.5 log in the UVC treated packs. Because the numbers of L. monocytogenes associated with contaminations of ready-to-eat meats are typically very low, the use of UVC in combination with PL and SDA has the potential to reduce the number of frankfurter recalls and foodborne illness outbreaks.