T3-05 An Assessment of Time/Temperature Combinations for Salmonella Lethality Achieved when Baking Cookies in Vehicles 

Monday, August 1, 2016: 9:30 AM
241 (America's Center - St. Louis)
Natalie Seymour, North Carolina State University, Raleigh, NC
Katrina Levine, North Carolina State University, Raleigh, NC
Ellen Thomas, North Carolina State University, Raleigh, NC
Eric Laber, North Carolina State University, Raleigh, NC
Benjamin Chapman, North Carolina State University, Raleigh, NC
Introduction: Consuming raw or undercooked baked goods is a risk for foodborne illness and has been linked to over 175 illnesses associated with five outbreaks. Pathogens including Salmonella spp. and E. coli O157:H7 have been associated with these products. The media has popularized attempts to bake cookies inside a vehicle on hot, sunny days, assuming a car simulates an oven without knowledge of safety.

Purpose: No data is currently available on the time/temperature profiles of a low-moisture raw cookie product during car baking and the safety of the final products. The goal was to see if vehicle-baked cookies reach a safe time/temperature combination.

Methods: The internal temperatures of car-baked cookies (n=8, 5 replicates) were measured during the summer of 2014 in North Carolina using two types of vehicles and two types of cookies. A data logger inserted into each of eight cookies, two of each type per vehicle, monitored temperature in five-minute intervals. Two additional data loggers monitored internal temperatures of each vehicle. Qualitative observations were taken at regular intervals and the experiment was repeated on five separate days of varying outside temperature.

Results: Based on the literature, a 3-log reduction of Salmonella can be achieved at 65°C for 10 minutes or 74°C for 1.5 minutes when water activity is 0.82.  All cookies achieved a safe time/temperature combination within four hours. Maximum internal temperatures ranged from 65.5°C to 88.6°C. Fifty-eight percent (n=36) reached 74°C in an average of 61 minutes and 39% reached 65°C in an average of 76 minutes. Cookies did not brown, were softer than traditional oven-baking and took an average of 183 minutes to appear set.

Significance: This experiment shows with average daytime temperature highs of 33°C (n=5), it is possible to bake cookies in a vehicle and achieve a 3-log reduction of Salmonella spp. within two hours.