Background and methodology
The goal of this study was to evaluate the quality of eggs available in Poland’s Tri-City market from conventional and organic poultry production systems. The study used analytical methods set by the Ministry of Agriculture and Rural Development in Poland, along with weight proportion of egg components, their pH, condition and index of egg white, and flattening and index of the yolk. Eggs came from two poultry facilities: one with all hens on one floor (conventional) and another that was a certified organic, free-range farm. Ten batches of eggs from each facility were examined. Each batch was comprised of 10 eggs. The study was conducted from June to July 2004.
Of the examined eggs from conventional facilities, 38 percent were classified as Class A eggs, 60 percent as Class B eggs and 2 percent as Class C eggs. An opposite proportion was observed for organic eggs: Class A eggs dominated (64 percent), whereas 32 percent of the examined eggs were Class B eggs and 4 percent Class C eggs. The size of air cell in organic eggs ranged from 2 to 5 mm, while in the conventional eggs the average was 4.3 mm. In this case, a statistically significant correlation was detected between both types of eggs. The examined eggs differed in weight and percent distribution of specific components. Free-range eggs, on average, had heavier yolks, a higher pH and dense white index than the conventional eggs. The type of hen raising method had a statistically significant influence on white index, yolk index and pH of yolk.
Smiechowska, M., and Dmowski, P. (2005). Influence of raising method on the quality of hen eggs. Polish Journal of Food and Nutrition Sciences, 14/55, SI 1,117-120. Available on-line at: http://journal.pan.olsztyn.pl//pdfy/2005/1s/21_smiechowska.pdf.