Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/20/2007
Publication Date: 1/1/2008
Citation: Sommers, C.H., Geveke, D.J., Fan, X. 2008. Flash Pasteurization inactivation of Listeria innocua on frankfurters that contain potassium lactate and sodium diacetate. Journal of Food Science. M1-M3.
Interpretive Summary: Listeria monocytogenes, a bacterium involved in foodborne illness, is an occasional contaminant on frankfurters. Both steam and antimicrobial compounds can be used to control the survival and growth of Listeria on the surface of frankfurters. In this study flash steam pasteurization (FP), in combination with the commonly used antimicrobials potassium lactate and sodium diacetate, were used to inactivate Listeria innocua on frankfurter surfaces. Listeria innocua is a nonpathogenic surrogate microorganism that can be used in open-air pilot plants in place of L. monocytognes. The use of steam (121C, 1.5s) inactivated 99 percent of the Listeria on frankfurters, while the antimicrobials inhibited the growth of survivors for 2 months during refrigerated storage. The treatments had no effect on frankfurter color or texture. Because the numbers of Listeria that contaminate frankfurters are typically very low, frankfurter manufacturers can use FP in combination with potassium lactate and sodium diacetate to provide safer frankfurters for consumers.
Technical Abstract: Listeria monocytogenes, a psychrotrophic food-borne pathogen, is a recurring 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. Flash (steam) pasteurization (FP) has been shown to reduce levels of L. monocytogenes, and its surrogate L. innocua, on frankfurter surfaces. The ability of FP to inactivate, and prevent the growth of the L. monocytogenes surrogate L. innocua, in a pilot plant setting, was investigated. FP treatment (1.5s, 121C) of single layers of frankfurters that were surface-inoculated with either 5 log, 4 log, or 3 log CFU/g of L. innocua immediately before FP (1.5s, 121C) resulted in log reductions of 1.97 (0.11), 2.03 (0.10), or 2.07 (0.14), respectively. Inoculum level had no effect on the inactivation of L. innocua. Following 8 weeks of refrigerated storage (4C) L .innocua levels decreased by 0.5 log in non-FP-treated frankfurter packs, while the 2 log reduction of L. innocua was maintained for FP treated frankfurters. FP (1.5s, 121C) had no effect on frankfurter color or texture. Because the numbers of L. monocytogenes associated with contaminations of ready-to-eat meats are typically very low, the use of FP in combination with PL and SDA has the potential to reduce the number of frankfurter recalls and foodborne illness outbreaks.