Purpose: The purpose of this study was to evaluate the thermal inactivation kinetics of Salmonella spp. and L. monocytogenes during pancake cooking process.
Methods: Whirlpak bags containing pancake batter samples were individually inoculated with cocktail strains of Salmonella spp. or L. monocytogenes cocktail to achieve target level of 108 CFU/g. Following inoculation, Whirlpak samples containing inoculated samples were treated at 160, 165, 170 or 175°F in pre-heated water bath. Treatment times varied with the temperature between 15 to 60 s. Product temperatures and come-up times were recorded. The study constituted 3 replicates. Samples inoculated with Salmonella spp. and Listeria monocytogenes were enumerated using scientifically valid methods. Water activity analysis was also performed. Log-transformed data was analyzed using ANOVA. The level of significance used was 5%.
Results: Overall, Salmonella spp. and L. monocytogenes populations significantly decreased (P < 0.05) with increase in treatment temperature and time. L. monocytogenes was relatively heat resistant (P < 0.05) when compared to Salmonella spp. A minimum 4-log reduction in Salmonella spp. and L. monocytogenes was observed when batter samples were treated at 160°F for 30 s and 160°F for 60 s, respectively. Water activity did not significantly differ (P > 0.05) between batter and cooked samples.
Significance: The study findings indicate that properly cooked pancakes (that achieve an internal temperature of 165°F or greater therefore, no longer a slurry and are suitable for sale) achieve acceptable lethality of vegetative pathogens from a food safety standpoint. The data in this study provides scientific basis for the ConAgra Foods frozen manufacturing facility’s food safety plan and support the use of an operational pre-requisite program for finished product quality as opposed to a CCP.