Changes in Lighting Conditions May Negatively Impact Perception of Doneness of Cooked Turkey Patties

Introduction: Undercooked poultry is a potential source of foodborne illnesses. It is recommended that a food thermometer be used to check the temperature of cooked meat; however, researchers report that most consumers do not use a thermometer, instead using visual appearance as a doneness indicator. Perception of visual appearance relies on many factors, including lighting conditions. The effects of the changes in home lighting options in recent years on perception of color and perhaps doneness of meat are unknown.

Purpose: This study evaluated the effect of lighting sources on consumer perception of doneness and likelihood to eat turkey patties cooked to different internal temperatures.  

Methods: Consumers (n=104) viewed standardized photographs of turkey patties cooked to six different internal temperatures, rated the perceived level of doneness of the patties and how likely they were to eat a patty that looked like the picture. Samples were viewed under five different lighting sources: 60 watt incandescent, and halogen, compact fluorescent, LED, and daylight LED lights at nominally the same lumen output. 

Results: Lighting source significantly changed the perception of doneness of the samples. Soft white LED and halogen lights increased the perception of doneness the most, with a higher percentage of viewers awarding “Just about right” scores to samples that were not at the recommended safe temperature. Several participants reported that they would eat the patties that were less done than “just about right.” Perception of doneness and likelihood to eat showed a discrepancy that should be further evaluated.

Significance: Recent changes in lighting regulations can affect perceptions of meat color, making it more likely that consumers will view poultry patties as done when they have not reached the appropriate temperature.  This lends strength to the message of using food thermometers as the only reliable method of determining doneness of meat patties.