Inactivation of Listeria innocua on Frankfurters by Ultraviolet Light and Flash Pasteurization

Abstract

Listeria monocytogenes, a psychrotrophic foodborne pathogen, is a recurring postprocess contaminant on ready-to-eat meat (RTE) products including frankfurters. Flash (Steam) Pasteurization (FP) and ultraviolet light (254 nm-UVC) has been shown to reduce levels of L. monocytogenes and L. innocua on frankfurters. In this study, the use of UVC light followed by FP to inactivate L. innocua, a nonpathogenic surrogate for L.monocytogenes, on frankfurters that contained sodium diacetate and potassium lactate (SDA/PL) in a pilot-plant setting was investigated. Application of UVC (1.0 J/cm2), followed by FP (0.75 s steam/121 degrees C) resulted in inactivation of 3.19 log L. innocua, while application of UVC (4.0 J/cm2), followed by FP (3 s steam/121 degrees C) resulted in inactivation of 3.89 log of L. innocua. A refrigerated storage study (8 degrees C) of frankfurters that contained SDA/PL that were treated with UVC followed by FP revealed the growth of L. innocua was inhibited for approximately 8 wk following application of the interventions. The use of UVC in combination with FP had little effect on frankfurter color and texture. The combination of UVC, FP, and SDA/PL was found to be an effective hurdle process for decontamination of frankfurter surfaces.