P1-82 Validation of a Frying Process to Control Salmonella in Donuts

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
Daniel Vega , Kansas State University , Manhattan , KS
George Milliken , Kansas State University , Manhattan , KS
Harshavardhan Thippareddi , University of Georgia , Athens , GA
Randall Phebus , Kansas State University , Manhattan , KS
Lakshmikantha Channaiah , AIB International , Manhattan , KS
Introduction:  Nonpasteurized, low moisture food ingredients, such as flour, sugar and milk powders, can be contaminated with pathogens such as Salmonella; therefore, FSMA mandates that all preventive control processing steps for ready-to-eat human foods be validated to control these foodborne pathogens.

Purpose:  This study validated a simulated commercial donut frying process against a seven-serovar Salmonella (Hartford, Newport, Senftenberg, Tennessee, Typhimurium, and two pet food isolates) cocktail, and determined the thermal inactivation parameters (D- and z-values) of the Salmonella cocktail in donut dough.

Methods:  Bread and pastry flour were mixed, inoculated with Salmonella cocktail, dried to preinoculation weight to achieve ~7.5 log CFU Salmonella/g population, and used to prepare donut dough. The donut frying process was validated using a 190.6°C oil temperature for one minute on each side followed by 30 minutes of ambient air-cooling. Population reductions were determined based on initial raw dough pathogen levels. Salmonella cocktail D-values in donut dough were determined using thermal-death-time disks and hot-water bath. Both studies utilized randomized complete block designs with three replications as blocks (P≤0.05).

Results:  The Salmonella population decreased by approximately one log CFU/g in donuts after one minute of frying; however, Salmonella was completely eradicated by the end of two minutes of frying. The D-values of the Salmonella cocktail in donut dough at 55, 58, and 61°C were 8.55, 2.87, and 2.13 min, respectively. The z-value was 10.03°C.

Significance:  This studied simulated a commercial donut frying process and achieved >7.5 log CFU Salmonella/g reduction in finished donuts when fried for one minute on each side at ~190.6°C oil temperature. As natural Salmonella contamination of ingredients, such as flour, is likely considerably <7 log CFU/g, frying donuts utilizing these validated parameters will provide a high level of assurance on product safety relative to Salmonella or similar vegetative pathogens.