Stevens, Scott Michael (2005-08). Microbial intervention strategies for Salmonella and Campylobacter reduction in commercial turkey processing. Master's Thesis.
Thesis
One objective of the present investigation was to compare Salmonella and Campylobacter recovery incidence from commercially processed turkeys immediately prior to and following pre-chill and immersion chiller intervention strategies being used in three distinct turkey processing facilities. In each plant, on a single day of processing, 100 carcass rinse samples prior to and following each post-evisceration, pre-chill intervention and following immersion chilling were obtained for Salmonella and Campylobacter recovery. Two of three plants demonstrated a trend of decreased Salmonella on carcasses following the Inside Outside Bird Wash (IOBW), with reductions of 13%, and 11% being observed for Plants 1 and 2, respectively. Results for reductions of Campylobacter contamination were not as straightforward, with only Plant 3 showing decreased levels (11% reduction) following the IOBW. Plant 2 used an additional pre-chill intervention, a low pressure, acetic acid final wash, which was not shown to be effective in causing an additional reduction in either Salmonella or Campylobacter on carcasses. In all three plants, properly managed immersion chilling systems were the most effective microbial intervention for achieving Salmonella andCampylobacter reduction on processed turkey carcasses. While not as effective, the IOBW present in each plant likely contributed to the effectiveness of immersion chiller interventions. If managed properly these intervention points have demonstrated themselves as a viable means to effectively reduce Salmonella and Campylobacter on processed turkeys. Another objective was to modify the scalder environment to an alkaline pH and determine the effects of thermal killing of Salmonella and Campylobacter. In each plant, on a single day of processing, 50 carcass rinse samples prior to and following scald tank immersion and following feather removal were obtained for Salmonella and Campylobacter recovery. Modification of the scald water to alkaline conditions (pH 9- 10) did not result in increased thermal killing of Salmonella or Campylobacter on turkey carcasses, as hypothesized before the investigation. Alkaline conditions are known to facilitate a more efficacious pluck and aid in the detachment of bacteria. Due to this, the bacteria that were recovered at these points on the processing line could have had an impact on the observed data.
