P1-81 Comparison of Heat Resistance of Salmonella during Simulated Commercial Baking of Hard and Soft Cookies

Monday, July 10, 2017
Exhibit Hall (Tampa Convention Center)
Minto Michael , Kansas State University , Manhattan , KS
Jennifer Acuff , Kansas State University , Manhattan , KS
Keyla Lopez , Kansas State University , Manhattan , KS
Lakshmikantha Channaiah , AIB International , Manhattan , KS
George Milliken , Kansas State University , Manhattan , KS
Harshavardhan Thippareddi , University of Georgia , Athens , GA
Randall Phebus , Kansas State University , Manhattan , KS
Introduction: Low moisture bakery ingredients, such as flour, sugar, egg solids and milk powders, can become contaminated with Salmonella; therefore, validated baking processes should be utilized to ensure finished product safety.

Purpose:  This study validated simulated commercial baking processes for hard and soft cookies to control Salmonella, and determined D- and z-values of a seven-serovar Salmonella (Hartford, Newport, Senftenberg, Tennessee, Typhimurium, and two pet food isolates from pet food) cocktail in cookie batters.

Methods: Cookie batters were prepared using flour mist-inoculated with the Salmonella cocktail (ca. seven log CFU/g). Hard and soft cookies were baked at 185°C for 16 min and 165.6°C for 22 min, respectively, followed by 30 min of ambient cooling. D-values of the cocktail in cookie batters were determined using thermal-death-time disks. Studies were designed as randomized complete blocks with three replications as blocks (a=0.05).

Results:  Salmonella populations decreased by >five log CFU/g in hard and soft cookies at 11.5 and 20.5 min of baking, respectively. Salmonella was completely eliminated in hard cookies at the end of baking (as determined by enrichment), whereas in soft cookies, 0.64 log CFU Salmonella/g was present at the end of baking and cooling. Salmonella D-values in hard cookie batter at 60, 65, and 70°C were 59.57, 28.08, and 11.85 min, respectively; while in soft cookie batter they were 62.29, 28.59, and 14.36 min, respectively. The Salmonella z-values in hard and soft cookie batters were 14.53 and 15.77°C, respectively.

Significance: This study validated the baking processes for hard and soft cookies; however, additional research should be conducted if inclusions such as dry fruits, nuts or chocolates are added in to the recipe, as these ingredients might impact the Salmonella lethality. The D- and z-values determined in cookie batters can be used by the bakery industry to evaluate the expected lethality of their baking schedules.