Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 12, 2007
Publication Date: January 1, 2008
Citation: Huang, L., Sites, J.E. 2008. Elimination of Listeria monocytogenes on Hotdogs by Infrared Surface Treatment. Journal of Food Science. 73:M27-M31. Interpretive Summary: Listeria monocytogenes is a pathogen that has been involved in several large-scale outbreaks of foodborne listeriosis associated with eating ready-to-eat (RTE) foods. A new post-lethality intervention technology been developed using infrared heat with an automatic feedback device for precise temperature control to inactivate L. monocytogenes that was surface-inoculated onto beef hotdogs. This study demonstrated that L. monocytogenes can be eliminated if using a proper combination of time and temperature during infrared surface pasteurization. If further developed, this technology may be used by the meat processing industry to reduce or eliminate the risk of foodborne listeriosis.
Technical Abstract: The objective of this research was to develop an infrared pasteurization process with automatic temperature control for inactivation of surface-contaminated Listeria monocytogenes on ready-to-eat meats such as hotdogs. The pasteurization system contained 4 basic elements: an infrared emitter, a hotdog roller, an infrared sensor, and a temperature controller. The infrared sensor was used to monitor the surface temperature of hotdogs while the infrared emitter, modulated by a power controller, was used as a heating source. The surface temperature of hotdogs was increased to set-points (70, 75, 80, or 85 C), and maintained for additional bacterial kill. The infrared surface pasteurization was evaluated using hotdogs that were surface-inoculated with a 4-strain L. monocytogenes cocktail to an average initial inoculum of 7.32 log (CFU/g). On average 1.0, 2.1, 3.0, or 5.3 log-reduction in L. monocytogenes was observed after the surface temperature of hotdogs was increased to 70, 75, 80, or 85 C, respectively. Holding the sample temperature led to additional bacterial inactivation. With a 3 min holding at 80 C or 2 min at 85 C, a total of 6.4 or 6.7 logs of L. monocytogenes were inactivated. This study demonstrated that the infrared surface pasteurization was effective in inactivating L. monocytogenes in RTE meats.