P1-62 Ultraviolet Light as a Post-lethality Treatment against Listeria monocytogenes on Bologna and Its Impact on Quality Attributes

Monday, July 29, 2013
Exhibit Hall (Charlotte Convention Center)
Deepika Suresh, Auburn University, Auburn, AL
Manpreet Singh, Auburn University, Auburn, AL
Introduction: Listeria monocytogenes is an important foodborne pathogen and a serious public health issue due to its severity of infection and high fatality rate. These high incidences are due to consumption of Listeria-contaminated foods, especially Ready-To-Eat (RTE) foods that do not require any additional heating/cooking post-processing, mandating post-lethality treatment to mitigate this pathogen.  

Purpose: To evaluate the efficacy of ultraviolet light against log and stationary phases of Listeria monocytogenes on bologna and its impact on quality and shelf life.

Methods: Listeria monocytogenes serotype 4a was cultured in Brain Heart Infusion (BHI) broth at 37°C. Cells were harvested at log and stationary phase, subjected to low (3–4 mW/sq. cm) and high (7-8 mW/sq. cm) intensity of UV. Listeria monocytogenes was inoculated on bologna followed by 30 min of attachment time; and then subjected to UV radiation from 0 to 300 s. Cells were recovered on Modified Oxford agar (MOX) after 24 h of incubation at 37°C. Additionally, shelf life along with quality attributes such as color and lipid oxidation (TBARS) were assessed over a period of 8 weeks on bologna stored at 0 and 4°C under vacuum.

Results: Populations of L. monocytogenes were significantly reduced (P < 0.05) after 150 s of UV exposure and subsequent reductions (P < 0.05) were observed up to 300 s irrespective of UV intensities. Higher (P < 0.05) reductions were observed in the log phase as compared to the stationary phase cells. Significant differences (P < 0.05) were observed in the L, a, b values at different storage temperature and exposure time over 8 weeks of storage. However, UV did not affect the lipid oxidation of bologna irrespective of the storage temperatures and time.

Significance: Significant reduction in L. monocytogenes population without affecting the quality attributes of bologna suggest the potential use of UV light as a post process intervention for RTE meats.