Eggs belong to the animal product category. They are laid by female animals. The most common types for human consumption include eggs laid by chickens, ducks, quail, roe and caviar. Bird and reptile eggs consist of an egg yolk and an egg white and a protective egg shell.
Egg varieties carried by retailers include brown- and white-colored eggs. They are further classified by the United States Department of Agriculture (USDA) based on the internal quality and their external appearance. Grades to be distinguished between include Grade AA, Grade A, and Grade B eggs. In the European Union, eggs are not graded by their quality but on their used farming method (organic or conventional, free range, barn range).
Eggs are a common food used in a large variety of dishes as they are a large supplier of protein and other valuable minerals and vitamins. On the breakfast table, they may be enjoyed –depending on the region – as a scrambled egg, hard-boiled egg or as a fried egg with the ‘sunny side up’.