External and Internal Quality Characteristics of Eggs Sourced in Supermarkets, General Dealers, and Vendors in Gaborone, Botswana

Egg quality characteristics influence consumer acceptance and preference of one egg over another. Several factors that impact egg quality include storage before and after dispatch, rearing conditions, temperature, handling, diseases, and the age of the eggs. The present study evaluated internal and external quality traits of eggs sourced from supermarkets, general dealers, and vendors in Gaborone, Botswana. One hundred and twenty eggs (24 eggs per location) were sourced from four supermarkets, seven general dealers, and 10 vendors in Gaborone. Parameters measured were egg weight (g), length (mm), width (mm), average shell thickness (mm), shell weight (g), surface area (cm2), volume (cm3), shape index, Haugh unit (HU), and shell weight per unit surface area (SWUSA, mg/cm2) of the eggs. The current results indicated that egg weight and surface area were the highest for eggs sourced from supermarkets. Heavier eggs correlated with better HU scores, indicating richer and denser yolk, while surface area plays a role in moisture loss and potential shell strength. Eggs purchased from supermarkets and general dealers had noticeably greater egg weights, egg volumes, shell percentages, and SWUSA. Eggs from supermarkets had the greatest egg content weight, whereas those purchased from vendors had the lowest. The HU was highest for supermarket eggs compared to other egg sources. It was observed that eggs bought from supermarkets had superior internal and external quality traits compared to those from general dealers and vendors. It was concluded that eggs from vendors had lower quality due to inadequate storage and cooling facilities compared to supermarkets and general dealers.