Eggs as food

Humans and other hominids have eaten eggs for millions of years, making them a very old and important food. The most common eggs people eat come from fowl, especially chickens. In places like Southeast Asia, people have been eating chicken eggs since around 1500 BCE.

Besides chicken eggs, people also eat eggs from other birds, like ducks and ostriches, though these are not as common. Some people also eat the eggs of reptiles, amphibians, and fish. When we eat fish eggs, we call them roe or caviar.

Today, hens and other egg-laying animals are raised all around the world. The making of chicken eggs has become a huge business, with millions of tons produced every year. There are many discussions about the best ways to raise these animals.

History

Bird eggs have been eaten for a very long time. People found eggs in nature and also raised birds to get more eggs. Chickens were first raised for their eggs in Southeast Asia and the Indian subcontinent long ago. They were taken to places like Sumer, Egypt, and Greece.

In ancient Rome, eggs were used to start meals. People would break the shells to keep away bad spirits.

During the Middle Ages, eggs were not eaten during Lent. This was because they were rich and to save food.

In the seventeenth century in France, people made scrambled eggs with sour fruit juices. This may have started the making of lemon curd.

Dried eggs became important during World War II to feed soldiers. The egg carton was invented in 1911 to keep eggs safe. Today, paper cartons are popular. Over many years, chickens have been bred to lay more eggs.

Varieties

Bird eggs are a common food used in cooking and the food industry. The most common eggs come from chickens, ducks, and geese. Smaller eggs, like quail eggs, are sometimes used in special dishes in Western countries. In Asia, such as China and Thailand, eggs are a regular part of meals.

Larger eggs, such as those from ostriches, are usually a special treat. Gull eggs are considered a delicacy in England and some Scandinavian countries, like Norway. In Africa, guineafowl eggs can be found in marketplaces in spring. Pheasant and emu eggs are edible but less common and may be found at farmers' markets or special grocery stores. In many places, laws protect wild bird eggs, so they can only be collected or sold at certain times of the year.

Production

In 2017, the world made a lot of chicken eggs. China made the most, followed by the United States, India, Mexico, Japan, Brazil, and Russia. During making, eggs are sometimes candled to check how good they are. This helps see the size of the egg's air space and if there might be a baby bird inside.

Anatomy and characteristics

Bird and reptile eggs have a hard shell, egg white, and a yolk inside. The yolk is kept in place by special strings called chalazae. The bigger end of the egg often has a tiny air space that forms after the egg is laid.

The color of the eggshell depends on the type of bird and what it eats. Eggs can be white, brown, or even blue. Egg white is mostly water and protein, and it becomes solid when you cook it. The color of the yolk depends on what the hen eats. Plants with yellow or orange pigments can make the yolk brighter. Sometimes eggs have two yolks or no yolk at all. This happens because of timing during how the egg forms.

Culinary properties

Chicken eggs are used in many dishes, both sweet and savory, such as baked goods, scrambled, fried, poached, boiled, and omelettes. Egg yolks help mix ingredients together and make dishes thicker, like in custards. Egg whites are filled with protein and can be whipped to make light, fluffy desserts such as meringues and mousse.

Eggs change when heated. Cooking eggs safely helps prevent illness from bacteria. Different methods, like soaking eggs in flavored mixtures, can change their taste. For example, tea eggs are flavored with spices, soy sauce, and black tea. Proper storage and preservation, such as using salt or vinegar, help keep eggs fresh and safe to eat.

Nutrition and health effects

Eggs are a great source of protein and choline. The United States Department of Agriculture used to call eggs "Meat" in its old food guide, but now uses MyPlate. Eggs have high-quality protein.

A medium chicken egg has about 70 kilocalories and 6 grams of protein. Cooking eggs changes their nutrition a little. For example, scrambled eggs lose a small amount of vitamin B12, while lightly fried eggs lose a bit more. Hard-boiled eggs lose the most.

The food we give hens can change the eggs. Hens that eat special foods like fish oil or flaxseeds make eggs with more good fats.

Cooked eggs are easier to digest and safer than raw eggs because they reduce the risk of getting sick.

Cholesterol and fat

Most of the calories in eggs come from the fat in the yolk. An egg has about five grams of fat, some of which is good for you. The egg white has almost no fat or cholesterol.

Some people worry about the cholesterol in egg yolks, but eating one egg a day is usually safe for healthy people’s hearts.

Type 2 diabetes

Studies do not agree on whether eating eggs changes the risk of type 2 diabetes. Some studies say eating many eggs might increase the risk, while others say it does not.

Cancer

Some studies say eating many eggs might increase the risk of certain cancers, but other studies do not find this to be true.

Cardiovascular health

Studies also do not agree on whether eggs affect heart health. Some say eating many eggs might increase the risk of heart problems, while others say eating up to one egg a day is safe for most people.

Other

Eating eggs does not seem to increase the risk of high blood pressure or stroke. Eggs also do not seem to cause inflammation in the body.

Contamination

Eggs can sometimes have harmful bacteria like Salmonella enteritidis. To stay safe, wash eggs right after they are laid, keep them cold, and cook them well. Most eggs in the U.S. are safe.

Food allergy

Eggs are one of the most common food allergies for babies. Many babies outgrow their egg allergy as they get older. People with egg allergies need to read food labels carefully.

Farming

See also: Poultry farming

Most chicken eggs we buy to eat are not fertilized. This is because hens are kept without roosters. Both kinds of eggs are safe to eat and have the same nutrition. Fertilized eggs won’t have a developed embryo because cooling them stops the cells from growing.

Eggs are sorted by quality and size. In the United States, the Department of Agriculture checks how clear the egg white is and how round the yolk is. Grade AA and Grade A eggs are best for cooking because they look nice.

The color of an eggshell does not change how the egg tastes, but some places like certain colors. In many parts of the United States, white eggs are common, while brown eggs are popular in places like New England. Brown eggs are also liked in China, France, and the United Kingdom. Some small farms sell eggs of many colors, such as white, brown, speckled, green, and blue.

Cultural significance

Further information: Egg decorating and Easter egg

Eggs are important in many cultures, especially during celebrations. In some places, people decorate hard-boiled eggs for Easter by dyeing or painting them. In parts of the world influenced by Persia, families decorate eggs before the spring equinox during the Persian New Year called Norouz.

In Northern Europe and North America, children often enjoy Easter egg hunts, where adults hide decorated eggs for them to find. In Eastern and Central Europe, and some parts of England, people might tap eggs together to see whose egg stays unbroken. In Barcelona and other Catalan cities, a special tradition during the feast of Corpus Christi involves balancing a hollow eggshell on a fountain’s water jet, making it spin without falling.