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From: The eUpdate, 07.27.10
No Differences Seen in Physical Quality of Retail Eggs
Study did not address nutritional quality
Commercially available eggs showed no substantial differences from one another in physical quality, no matter what production system was used, a study found. Specialty eggs such as cage-free, fertile, or nutritionally enhanced specialty types showed no differences in physical quality from traditional eggs, the researchers found.
“Although significant differences were found between white and brown shell eggs and production methods, average values for quality attributes varied without one egg type consistently maintaining the highest or lowest values,” said Deana R. Jones, PhD, a research food technologist in the U.S. Department of Agriculture’s (USDA) Agricultural Research Service. Dr. Jones was first author of a paper describing the study’s findings (Jones DR, Musgrove MT, Anderson KE, et al. Poult Sci. 2010;89(3):582-587).
The researchers purchased a variety of large white and brown eggs with various production and nutritional differences (traditional, cage-free, free-roaming, pasteurized, nutritionally enhanced, and fertile) from retail outlets in Athens, Ga. They measured the physical quality of the eggs using Haugh units, tools that are widely used for the measurement of interior egg quality. The research did not address flavor or overall nutritional quality.
Haugh unit values ranged from 66.67 (for cage-free and docosahexaenoic acid-enhanced) to 84.42 (for traditional white). Brown eggs had greater weight and greater static compression shell strength than white eggs, the researchers found. Percentage of total solids was greatest in cage-free eggs, and crude fat was greatest in nutritionally enhanced white eggs.
Dr. Jones explained in an e-mail to Food Quality magazine that egg candling, widely used to assess egg quality, is subjective. She said the USDA has accepted the Haugh unit, which uses a correlation between egg weight and the height of the thick albumen, as a valid and reliable method for determining egg quality.