Influence of storage conditions on quality and safety of eggs collected from Lebanese farms

Abstract

Egg is considered a nutritionally complete food and an excellent source of protein. However, storing eggs for a prolonged period of time under uncontrolled temperature results in egg quality deterioration. The objective of this study is to determine the effect of storage conditions (time & temperature) on the egg's internal and external quality parameters as well as the microbiological load of eggs. For that purpose, a total of 2160 (white, brown vaccinated and brown non-vaccinated for salmonella) eggs were collected from Lebanese egg farmers in Bekaa valley and stored at 7 °C, 18 °C, 24 °C and 33 °C/20 °C (cyclic) for 2, 4 and 6 weeks. At each time point and temperature setting, 30 eggs were analysed for external and internal quality traits as well microbiological testing. Results showed that brown eggs had significantly higher weight (P < 0.001), shell thickness (P < 0.01), and darker yolk colour than white eggs. As the storage temperature and time increased, a decrease in Haugh unit (HU) and yolk colour was observed (p < 0.05). In addition, a decrease (p < 0.001) in the egg weight, specific gravity and shell thickness. For the eggs microbial analysis, a total absence was observed for eggs stored at 7 °C at all-time points. The results suggest that the interaction between temperature, time, and group significantly affect the eggs internal and external quality, by causing significant deterioration in HU, yolk colour, weigh, specific gravity, and shell thickness. This work has concluded that eggs should be stored at a refrigerated temperature (7 °C) for a period not exceeding 4 weeks.