Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/8/2006
Publication Date: 8/13/2006
Citation: Groulescu, C., Juneja, V.K., Ravishankar, S. 2006. Effects and interactions of sodium lactate, sodium diacetate, and pediocin on the thermal inactivation of starved cells of listeria monocytogenes on the surface of bologna. Meeting Abstract.
Technical Abstract: The effects and interactions of sodium lactate, sodium diacetate, and pediocin on the thermal inactivation of starved cells of Listeria monocytogenes on the surface of bologna were investigated. The heating temperatures used in the study were 56.3 to 60 degrees C and the antimicrobials were: sodium lactate (SL), 0.0 to 4.8%w/w; sodium diacetate (SDA), 0.0 to 0.25%w/w; and pediocin (P), 0.0 to 10000AU. Thermal treatment of bologna was done in vacuum packaged bags submerged in a circulating water bath set at the specified temperatures. The samples were plated on the modified Oxford formulation, and brain heart infusion agars. Decimal reduction times (D-values) were calculated using linear regression. The observed D-values ranged from 2.8 min at 60 degrees C to 24.61 min at 56.3 degrees C. Injury ranged from 9.1 to 76 %, and it was seen in all experiments under all conditions studied. The observed D-values were analyzed using second order response surface regression for temperature, SL, SDA, and pediocin and a multiple second order regression equation was developed. The predicted D-values were calculated, and they showed a good correlation with the observed D-values. A predictive model was developed. Temperature had the most significant effect on the inactivation of starved cells of L. monocytogenes on the surface of bologna. The combination of temperature with all the antimicrobials (SL, SDA and pediocin) showed significant effect in inactivating the starved cells of L. monocytogenes. The combinations between pediocin and SL, and pediocin and SDA showed significance also. The combination of SL and SDA rendered L. monocytogenes on the surface of bologna less resistant to heat. The model can predict D-values for any combinations of temperature, SL, SDA and pediocin within the tested range of factors.