Qality traits of retail eggs produced by alternative and cage rearing systems

Thesis Type: Postgraduate

Institution Of The Thesis: Bursa Uludağ University, Sağlık Bilimleri Enstitüsü, Turkey

Approval Date: 2020

Thesis Language: Turkish

Student: Eda İlhan Tekin



This study, which was conducted to determine the compliance of outer and inner quality traits of retail brown and white grade A table eggs with respect to Turkish Egg Regulation and Standard, a total of 350 eggs comprised of 200 brown (50 from each system), and 150 white (each 50, except free-range) produced by alternative (organic, free-range and barn) and cage systems, were analyzed. Effect of rearing system was statistically significant in brown eggs for shape index, shell weight, shell strength and Haugh Unit (HU), and in white eggs for all outer and inner quality traits except shape index, shell thickness and air cell height (p<0.05). All samples complied with the egg weight requirements, while air cell height of free-range brown eggs was found higher (6.75 mm), thus non-compliant than the indicated upper limit indicated in Turkish Food Codex Egg Directive 2014/55. Cage system white eggs' HU values were in compliance with the Turkish Standard for Chicken Egg - in Shell (TS1068), while this value was lower than the required limits in free-range and cage brown eggs. Cage brown eggs had higher shape index (%79-spherical), while white eggs had lower shell weight (7.26 g); free-range and cage brown eggs had thicker shells (0.32 mm), and organic white and cage brown eggs had the strongest shell; the darkest and the faintest yellow were in cage white and organic eggs, respectively. In conclusion, there is no 'one ideal' rearing system to produce eggs compliant to all quality traits, and thus the systems can have advantages/disadvantages effecting outer and inner quality of eggs.