There's no substantial quality difference between organically and conventionally produced eggs, says a study conducted by the Agricultural Research Service, an agency that operates under the U.S. Department of Agriculture.

ARS food technologist Deana Jones and her team in the agency's egg safety and quality research unit in Athens, Ga., found that, on average, there was no substantial quality difference between types of eggs. So, no matter which specialty egg is chosen, it will be nearly the same quality as any other eggs, researchers say.

Their findings were published recently in the journal Poultry Science.

About 6.5 billion dozen shell egg—with a total value of about $7 billion—are produced annually in the U.S., says the USDA's Economic Research Service.

The ARS team found that the biggest difference between eggs was the size of egg within a carton between brown and white eggs. Though brown eggs weighed more, white shell eggs had higher percentages of total solids and crude fat. The study found, though, that there was no significant difference in the quality of white and brown eggs.

Quality is measured by Haugh units, named after Raymond Haugh. In 1937, he developed the Haugh unit as a correlation between egg weight and the height of the thick albumen, or thickest part of the egg white. The Haugh unit has become the most widely used measurement of interior egg quality and is considered to be the "gold standard" of interior egg quality determination.

Jones and her team conducted a survey of white and brown large-shell eggs with various production and nutritional differences such as traditional, cage-free, free-roaming, pasteurized, nutritionally-enhanced, and fertile. The goal was to determine if physical quality and compositional differences exist among these different eggs.

Among the claims most often addressed on shell egg cartons are husbandry practices, hen nutrition, enhanced egg nutrition (omega-3), organic, and fertile. Pricing for such eggs typically is higher than for standard eggs, but can vary from market to market.