Chicken egg (left) and quail eggs (right), types of egg commonly used as food

An egg is a round or oval body laid by the female of many animals, consisting of an ovum surrounded by layers of membranes and an outer casing, which acts to nourish and protect a developing embryo and its nutrient reserves. An ovum (plural ova) is a Haploid Female reproductive cell or Gamete. An embryo (from Greek:, plural, lit "that which grows" from en- "in" + bryein "to swell be full" is a multicellular Most edible eggs, including bird eggs and turtle eggs, consist of a protective, oval eggshell, the albumen (egg white), the vitellus (egg yolk), and various thin membranes. Birds ( class Aves) are bipedal endothermic ( Warm-blooded) Vertebrate animals that lay eggs. Turtles are Reptiles of the Order Testudines (all living turtles belong to the Crown group Chelonia) most of The term eggshell is a term for the outer covering of a hard-shelled egg, and some forms of eggs with soft outer coats Albumen redirects here For other uses see Albumen (disambiguation. An egg yolk is the part of an egg which serves as the Food source for the developing Embryo inside Every part is edible, although the eggshell is generally discarded. Nutritionally, eggs are considered a good source of protein and choline. Proteins are large Organic compounds made of Amino acids arranged in a linear chain and joined together by Peptide bonds between the Carboxyl Choline is an Organic compound, classified as a water-soluble Essential nutrient and usually grouped within the Vitamin B complex

Roe and caviar are edible eggs produced by fish. Roe or hard roe is the fully ripe internal ovaries or egg masses of Fish and certain marine Animals such as Shrimp, Scallop Caviar is the processed, Salted Roe of certain species of Fish, most notably the Sturgeon ( black caviar) and the Fish are aquatic Vertebrate animals that are typically ectothermic (previously Cold-blooded) covered with scales, and equipped with two

Culinary use

See also: List of egg dishes

Ostrich egg (right), compared to chicken egg and quail eggs

Bird eggs are a common food and one of the most versatile ingredients used in cooking. The following is a list of egg dishes Plain egg dishes Coddled egg Fried egg Boiled egg Birds ( class Aves) are bipedal endothermic ( Warm-blooded) Vertebrate animals that lay eggs. Food is any substance usually composed primarily of Carbohydrates Fats water and/or Proteins that can be eaten or drunk by an They are important in many branches of the modern food industry. The food industry is the complex global collective of diverse Businesses that together supply much of the Food energy consumed by the World population. ^[1] The most commonly used bird eggs are those from the chicken. The chicken ( Gallus gallus, sometimes G gallus domesticus) is a domesticated Fowl which is traditionally believed to have descended from Duck and goose eggs, and smaller eggs such as quail eggs are occasionally used as a gourmet ingredient, as are the largest bird eggs, from ostriches. For duck as a food see Duck (food; for other meanings see Duck (disambiguation. Goose (plural geese) is the English name for a considerable number of Birds belonging to the family Anatidae. Quail is a collective name for several genera of mid-sized Birds in the Pheasant family Phasianidae, or in the family Odontophoridae. The Ostrich ( Struthio camelus) is a large Flightless bird native to Africa (and formerly the Middle East) Gull eggs are considered a delicacy in England,^[2] as well as in Scandinavian countries, particularly in Norway. Gulls (often informally Seagulls) are birds in the family Laridae England is a Country which is part of the United Kingdom. Its inhabitants account for more than 83% of the total UK population whilst its mainland Norway ( Norwegian: Norge ( Bokmål) or Noreg ( Nynorsk) officially the Kingdom of Norway, is a Constitutional In some African countries, guineafowl eggs are commonly seen in marketplaces, especially in the spring of each year. The guineafowl (sometimes called guineahen are a family of birds in the same order as the Pheasants turkeys and other game birds and is native to ^[3] Pheasant eggs and emu eggs are perfectly edible but less widely available. Pheasants are a group of large Birds in the order Galliformes. The Emu ( Dromaius novaehollandiae, is the largest Bird native to Australia and the only extant member of the Genus ^[2] Sometimes they are obtainable from farmers, poulterers, or luxury grocery stores. Most wild bird's eggs are protected by laws in many countries, which prohibit collecting or selling them, or only permit these during specific periods of the year. ^[2]

Fried chicken egg

Most commercially produced chicken eggs intended for human consumption are unfertilized, since the laying hens are kept without roosters. A rooster (also called a cock or chanticleer) is a male Chicken ( Gallus gallus) the female being called a Hen. Fertile eggs can be purchased and eaten as well, with little nutritional difference. Fertile eggs will not contain a developed embryo, as refrigeration prohibits cellular growth for an extended amount of time.

Chicken eggs are widely used in many types of dishes, both sweet and savory. Eggs can be pickled, hard-boiled, scrambled, fried and refrigerated. Pickling, also known as brining or corning, is the process of preserving Food by Anaerobic fermentation in Brine (a solution They can also be eaten raw, though this is not recommended for people who may be especially susceptible to salmonella, such as the elderly, the infirm, or pregnant women. Salmonella is a Genus of rod-shaped Gram-negative enterobacteria that causes Typhoid fever, Paratyphoid fever In addition, the protein in raw eggs is only 51% bio-available, whereas that of a cooked egg is nearer 91% bio-available, meaning the protein of cooked eggs is nearly twice as absorbable as the protein from raw eggs. ^[4] As an ingredient egg yolks are important emulsifier in the kitchen, and the proteins in eggs white makes all kinds of foams and aerated dishes possible. An emulsion ( IPA: /ɪˈmʌlʃən/ is a mixture of two Immiscible (unblendable liquids

Soft-boiled quail eggs, with potato galettes

Quail eggs are considered a delicacy in many countries. They are used raw or cooked as tamago in sushi. In Japanese cuisine, is Vinegared Rice, usually topped with other ingredients including fish various meats and vegetables In Colombia, quail eggs are considered less exotic than in other countries, and a single hard-boiled quail egg is a common topping on hot dogs and hamburgers, often fixed into place with a toothpick. Colombia (kəˈlʌmbɪə officially the Republic of Colombia () is a country in northwestern South America. Boiled eggs are eggs (typically Chicken 's eggs cooked by immersion in boiling water with their shells unbroken A hot dog is a type of fully-cooked cured and/or smoked moist Sausage of soft even texture and flavor A hamburger (or burger) is a Sandwich consisting of a cooked ground Meat Patty, usually Beef, placed in a sliced bun or between A toothpick is a small stick of Wood, Plastic, Bamboo, Metal or other substance used to remove detritus from the Teeth, usually after

A boiled egg can be distinguished from a raw egg without breaking the shell by spinning it. Boiled eggs are eggs (typically Chicken 's eggs cooked by immersion in boiling water with their shells unbroken A hard-boiled egg's contents are solid due to the denaturation of the protein, allowing it to spin freely, while viscous dissipation in the liquid contents of a raw egg causes it to stop spinning within approximately three rotations. Denaturation is a process in which Proteins or Nucleic acids lose their structure (tertiary structure by application of some external stress or compound for Proteins are large Organic compounds made of Amino acids arranged in a linear chain and joined together by Peptide bonds between the Carboxyl Viscosity is a measure of the resistance of a Fluid which is being deformed by either Shear stress or Extensional stress. In Physics, dissipation embodies the concept of a Dynamical system where important mechanical modes such as Waves or Oscillations lose Energy

The albumen, or egg white contains protein but little or no fat. It is used in cooking separately from the yolk, and can be aerated or whipped to a light, fluffy consistency. The albumen is the healthiest bit of the egg. Beaten egg whites are used in desserts such as meringues and mousse. Meringue is a type of Dessert made from whipped Egg whites and caster sugar. Mousse ( is a form of creamy Dessert typically made from egg and Cream (classically no cream only egg yolks egg whites sugar and chocolate or other Ground egg shells are sometimes used as a food additive to deliver calcium. Food additives are substances added to food to preserve flavour or improve its taste and appearance Calcium (ˈkælsiəm is the Chemical element with the symbol Ca and Atomic number 20 ^[5] Boiled eggs that are difficult to peel are usually too fresh. Fresh eggs have a lower pH, and this does not allow the shell to separate easily from the underlying albumen. pH is the measure of the acidity or alkalinity of a Solution. Albumen redirects here For other uses see Albumen (disambiguation. When put into vinegar the shell will dissolve slowly.

Flavor

Although the age of egg and the conditions of its storage have a greater influence, the bird's diet does affect the flavor of egg. ^[6] For example, when a brown-egg chicken breed eats rapeseed or soy meals, its intestinal microbes metabolize them into fishy-smelling triethylamine, which ends up in the egg. Rapeseed ( Brassica napus) also known as rape, oilseed rape, rapa, rapaseed and (in the case of one particular group of Triethylamine is the Chemical compound with the formula N(CH2CH33 commonly abbreviated Et 3N ^[6] The unpredictable diet of free-range hens will produce unpredictable eggs. ^[6]

Problems with cooking

If a boiled egg is overcooked, a greenish ring sometimes appears around egg yolk. This is a manifestation of the iron and sulfur compounds in the egg. Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 Sulfur or sulphur (ˈsʌlfɚ see spelling below) is the Chemical element that has the Atomic number 16 It can also occur when there is an abundance of iron in the cooking water. The green ring does not affect the egg's taste; overcooking, however, harms the quality of the protein (chilling the egg for a few minutes in cold water until the egg is completely cooled prevents the greenish "ring” from forming on the surface of the yolk).

Cooking also increases the risk of atherosclerosis due to increased oxidization of the cholesterol contained in the egg yolk. Atherosclerosis is a Disease affecting arterial Blood vessels It is a chronic inflammatory response in the walls of arteries in large part due to the accumulation Beta oxidation is the process by which Fatty acids in the form of Acyl-CoA molecules are broken down in Mitochondria and/or in Peroxisomes to Cholesterol is a Lipid found in the Cell membranes and transported in the Blood plasma of all Animals It is an essential component of mammalian An egg yolk is the part of an egg which serves as the Food source for the developing Embryo inside ^[7]

Substitutes

For those who do not consume eggs, alternatives used in baking include other rising agents or binding materials, such as ground flax seeds or potato flour. Flax (also known as common flax or linseed) (binomial name Linum usitatissimum) is a member of the genus Linum Flour is a powder made of Cereal grains It is the key ingredient of Bread, which is a staple food in many countries and therefore the availability Tofu can also act as a partial binding agent, since it is high in lecithin due to its soy content. Tofu, also (the Japanese Romaji spelling doufu (the Chinese Pinyin spelling often used in Chinese recipes or bean curd (the literal Applesauce can be used as well as arrowroot and banana. Apple sauce (or applesauce) is a Purée made from Apples It can use peeled or unpeeled apples and a variety of spices or additives such as Cinnamon Arrowroot, or obedience plant ( Maranta arundinacea) is a large perennial Herb of genus Maranta found in Rainforest For the fruit see Banana. For other meanings see Banana (disambiguation. Extracted soybean lecithin, in turn, is often used in packaged foods as an inexpensive substitute for egg-derived lecithin. Lecithin is any of a group of yellow-brownish fatty substances occurring in animal and plant tissues and in egg yolk composed of Phosphoric acid, Choline,

Other egg substitutes are made from just the white of the egg for those who worry about the high cholesterol and fat content in eggs. These products usually have added vitamins and minerals as well as vegetable-based emulsifiers and thickeners such as xantham gum or guar gum. Xanthan gum is a Polysaccharide used as a Food additive and Rheology modifier. Guar gum, also called guaran, is a Galactomannan. It is primarily the ground Endosperm of Guar beans The guar seeds are dehusked milled These allow the product to maintain the nutrition found in an egg as well as several culinary properties of real eggs. This makes it possible for food like Hollandaise sauce, custard, mayonnaise, as well as most baked goods to be prepared using these substitutes. Hollandaise sauce is an Emulsion of Butter and Lemon juice using Egg yolks as the emulsifying agent usually seasoned with Salt and Custard is a range of preparations based on Milk and eggs thickened with heat Mayonnaise (sometime abbreviated to mayo in American English and other languages is a thick Condiment made primarily from Vegetable oil and Egg

Preservation

Salted duck egg

The simplest method to preserve an egg is to treat it with salt. Salt is a Dietary mineral composed primarily of Sodium chloride that is essential for Animal life but toxic to most land plants Salt draws water out of bacteria and molds, which prevents their growth. The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have WikipediaManual_of_Style#National_varieties_of_English --> Molds (or ^[8] The Chinese salted duck egg is made by immersing duck eggs in brine, or coating them individually with a paste of salt and mud or clay. Salted duck egg is a Chinese preserved food product made by soaking Duck eggs in Brine, or packing each egg in damp salted Charcoal Brine (lat saltus) is Water saturated or nearly saturated with Salt (NaCl In computer gaming, a MUD ( Multi-User Dungeon, Domain or Dimension) is a multi-player computer game that combines elements of Clay is a naturally occurring material composed primarily of fine-grained Minerals which show plasticity through a variable range of Water content, and The eggs stop absorbing salt after about a month, having reached chemical equilibrium. In a Chemical process, chemical equilibrium is the state in which the chemical activities or Concentrations of the reactants and products have no net change ^[8] Their yolks become an orange-red colored solid, but the white remains liquid. They are boiled before consumption and often served with rice congee.

Pickled egg, colored with beetroot juice

Another method is to make pickled eggs, by boiling them first and immersing them in a mixture of vinegar, salt, and spices like ginger or allspice. Preparation After the eggs are hard boiled the shell is removed and they are submerged in a solution of Vinegar, salt spices and other seasonings Ginger is commonly used as a cooking spice throughout the world Allspice, also called Jamaica pepper,"Kurundu" Myrtle pepper, pimento, or newspice, is a Spice which is the dried unripe Frequently, beetroot juice is added to impart a red color to the eggs. The beet or beetroot is a Flowering plant species ( Beta vulgaris) in the family Chenopodiaceae. ^[9] If the eggs are immersed in it for a few hours, the distinct red, white, and yellow colors can be seen when the eggs are sliced. ^[9] If marinated for several days or more, the red color will reach to the yolk. ^[9] If the eggs are marinated in the mixture for several weeks or more, vinegar's acetic acid will dissolve much of the shell's calcium carbonate and penetrate the egg, making it acidic enough to inhibit the growth of bacteria and molds. Acetic acid, also known as ethanoic acid, is an organic chemical compound, giving Vinegar its sour taste Calcium carbonate is a Chemical compound with the Chemical formula Ca[[Carbon C]] O 3 In Computer science, ACID ( Atomicity Consistency Isolation Durability) is a set of properties that guarantee that Database transactions are ^[8] Pickled eggs made this way will generally keep for a year or more without refrigeration. ^[8]

Century egg

A century egg or thousand-year-old egg is preserved by fermenting an egg in a mixture of clay, wood ash, salt, lime, and rice straw for several weeks to several months, depending on the method of processing. Century egg, also known as preserved egg, hundred-year egg, thousand-year egg, and thousand-year-old egg, is a Chinese cuisine Clay is a naturally occurring material composed primarily of fine-grained Minerals which show plasticity through a variable range of Water content, and Calcium oxide ( CaO) commonly known as burnt lime, lime or quicklime, is a widely used Chemical compound. After the process is completed, the yolk becomes a dark green, cream-like substance with a strong odor of sulfur and ammonia, while the white becomes a dark brown, transparent jelly with a comparatively mild, distinct flavor. The transforming agent in a century egg is its alkaline material, which gradually raises the pH of the egg from around 9 to 12 or more. In Chemistry, an alkali (from Arabic: Al-Qaly القلي القالي) is a basic, ionic salt of an Alkali metal pH is the measure of the acidity or alkalinity of a Solution. ^[10] This chemical process causes an "inorganic version" of fermentation, which breaks down some of the complex, flavorless proteins and fats of the yolk into simpler, flavorful ones.

History

Bird eggs have been valuable foodstuff since prehistory, in both hunting societies and more recent cultures where birds were domesticated. Stone Age Paleolithic See also Paleolithic, Recent African Origin, Early Homo sapiens, Early human migrations "Paleolithic" In Thebes, Egypt, the tomb of Haremhab, built about 1420 BCE, shows a depiction of a man carrying bowls of ostrich eggs and other large eggs, presumably those of the pelican, as offerings. Thebes ( Thēbai) was a city in Ancient Egypt located about 800 km south of the Mediterranean on the east bank of the river Nile ( A pelican is a large water Bird with a distinctive pouch under the beak belonging to the Bird family Pelecanidae. ^[11] In ancient Rome, eggs were preserved using a number of methods, and meals often started with an egg course. Ancient Rome was a Civilization that grew out of a small agricultural community founded on the Italian Peninsula as early as the 10th century BC ^[11] The Romans crushed the shell in their plate to prevent evil spirits from hiding there. ^[1] In the Middle Ages, eggs were forbidden during Lent because of their richness. Lent, in some Christian denominations, is the forty-day-long liturgical season of fasting and prayer before Easter. ^[1] It is possible that the word mayonnaise was derived from moyeu, the medieval French word for the yolk meaning center or hub. Mayonnaise (sometime abbreviated to mayo in American English and other languages is a thick Condiment made primarily from Vegetable oil and Egg ^[1]

Egg scrambled with acidic fruit juices were popular in France in the 17th century; this may have been the origin of lemon curd. ^[6]

The dried egg industry developed in the 19th century, before the rise of the frozen egg industry. ^[12] In 1878, a company in St. Louis, Missouri started to transform egg yolk and white into a light-brown, meal-like substance by using a drying process. ^[12] The production of dried eggs significantly expanded during World War II, for use by the United States Armed Forces and its allies. World War II, or the Second World War, (often abbreviated WWII) was a global military conflict which involved a majority of the world's nations, including ^[12]

The egg carton was invented by Joseph Coyle in Smithers, British Columbia, to solve a dispute about broken eggs between a farmer in Bulkley Valley and the owner of the Aldermere Hotel. An egg carton is a Carton designed for carrying and transporting whole eggs These cartons have a dimpled form in which each dimple accommodates an individual Smithers is a town located in northwestern British Columbia, Canada, approximately halfway between Prince George and Prince Rupert. The Bulkley Valley is located in west central British Columbia, Canada. Early egg cartons were made of paper. ^[13]

Anatomy and characteristics

See also: Egg (biology)

Schematic of a chicken egg:
1. In most Birds and Reptiles an egg ( Latin ovum) is the Zygote, resulting from Fertilization of the Ovum. Eggshell
2. Outer membrane
3. Inner membrane
4. Chalaza
5. Exterior albumen
6. Middle albumen
7. Vitelline membrane
8. Nucleus of pander
9. Germinal disk
10. Yellow yolk
11. White yolk
12. Internal albumen
13. Chalaza
14. Air cell
15. Cuticula

The shape of an egg is an ovate spheroid with one end larger than the other end. Equation A spheroid centered at the origin and rotated about the z axis is defined by the implicit equation \left(\frac{x}{a}\right^2+\left(\frac{y}{a}\right^2+\left(\frac{z}{b}\right^2 The egg has cylindrical symmetry along the long axis.

An egg is surrounded by a thin, hard shell. Inside, the egg yolk is suspended in the egg white by one or two spiral bands of tissue called the chalazae (from the Greek word khalazi, meaning hailstone or hard lump. The chalaza (from Greek - khalaze - meaning "hailstone" is a structure inside animal eggs and plant Ovules It attaches or suspends the Yolk )

Air cell

The larger end of the egg contains the air cell that forms when the contents of the egg cool down and contract after it is laid. Chicken eggs are graded according to the size of this air cell, measured during candling. Candling is a method used in Embryology to study the growth and development of an Embryo inside an egg. A very fresh egg has a small air cell and receives a grade of AA. As the size of the air cell increases, and the quality of the egg decreases, the grade moves from AA to A to B. This provides a way of testing the age of an egg: as the air cell increases in size, the egg becomes less dense and the larger end of the egg will rise to increasingly shallower depths when the egg is placed in a bowl of water. A very old egg will actually float in the water and should not be eaten. ^[14] Although there is no significant link between shell color and nutritional value, there is often a cultural preference for one color over another. For example, in most regions of the United States, chicken eggs are generally white; while in the northeast of that country and in the United Kingdom, they are generally light-brown. The United States of America —commonly referred to as the The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located In Brazil and Poland, white chicken eggs are generally regarded as industrial, and brown or reddish ones are preferred. |utc_offset = -2 to -4 |time_zone_DST = BRST |utc_offset_DST = -2 to -5 |cctld Poland (Polska officially the Republic of Poland

White (Albumen)

Main article: Egg white

Yolk

Main article: Egg yolk

The yolk in a newly laid egg is round and firm. Albumen redirects here For other uses see Albumen (disambiguation. An egg yolk is the part of an egg which serves as the Food source for the developing Embryo inside An egg yolk is the part of an egg which serves as the Food source for the developing Embryo inside As the yolk ages it absorbs water from the albumen which increases its size and causes it to stretch and weaken the vitelline membrane (the clear casing enclosing the yolk). The vitelline membrane is a structure directly adjacent to the outer surface of the Plasma membrane of an Ovum. The resulting effect is a flattened and enlarged yolk shape.

Yolk color is dependent on the diet of the hen; if the diet contains yellow/orange plant pigments known as xanthophylls, then they are deposited in the yolk, coloring it. For the drug referred to as "pigment" see Black tar heroin. Xanthophylls (originally phylloxanthins) are yellow Pigments from the Carotenoid group A colorless diet can produce an almost colorless yolk. Farmers may enhance yolk color with artificial pigments, or with natural supplements rich in lutein (marigold petals are a popular choice), but in most locations, this activity is forbidden. As a pigment This Xanthophyll, like its sister compound Zeaxanthin, has primarily been used as a natural colorant due to its Orange-red Color

Abnormalities

A hardboiled double-yolked egg, cut in half

Some hens will lay double-yolked eggs as the result of unsynchronized production cycles. Although heredity causes some hens to have a higher propensity to lay double-yolked eggs, these occur more frequently as occasional abnormalities in young hens beginning to lay. Usually a double-yolked egg will be longer and thinner than an ordinary single-yolk egg. Double-yolked eggs occur rarely, only leading to observed successful hatchings under human intervention, as the unborn chickens would otherwise fight each other and die. ^[15]

It is also possible for a young hen to produce an egg with no yolk at all. Yolkless eggs are usually formed about a bit of tissue that is sloughed off the ovary or oviduct. This tissue stimulates the secreting glands of the oviduct and a yolkless egg results.

Health issues of eating chicken eggs

Cholesterol and fat

More than half the calories found in eggs come from the fat in the yolk; a 100 gram chicken egg contains approximately 10 grams of fat. People on a low-cholesterol diet may need to reduce egg consumption, although only 27% of the fat in egg is saturated fat (Palmitic,Stearic and Myristic acids) that contains LDL cholesterol. Saturated fat is Fat that consists of Triglycerides containing only saturated Fatty acids Explanation Fat that occurs The egg white consists primarily of water (87%) and protein (13%) and contains no cholesterol and little, if any, fat. Albumen redirects here For other uses see Albumen (disambiguation.

There is debate over whether egg yolk presents a health risk. Some research suggests dietary cholesterol increases the ratio of total to HDL cholesterol and, therefore, adversely affects the body's cholesterol profile; ^[16] whereas other studies show that moderate consumption of eggs, up to two per day, does not appear to increase heart disease risk in healthy individuals. High-density lipoproteins ( HDL) is one of the 5 major groups of Lipoproteins ( Chylomicrons, VLDL, IDL, LDL, HDL Heart disease is an Umbrella term for a variety for different diseases affecting the Heart. ^[17] Harold McGee argues that the cholesterol in the yolk is not what causes a problem as fat (particularly saturated) is much more likely to raise cholesterol levels than the actual consumption of cholesterol. Harold McGee is an American author who writes about the Chemistry, technique and history of food and cooking and has written two books on kitchen science ^[14] A 2007 study of nearly 10,000 adults demonstrated no correlation between moderate (6 per week) egg consumption and cardiovascular disease or strokes except in the sub-population of diabetic patients which presented an increased risk of coronary heart disease. Cardiovascular disease or cardiovascular diseases refers to the class of diseases that involve the Heart or Blood vessels ( arteries and A stroke is the rapidly developing loss of brain functions due to a disturbance in the blood vessels supplying blood to the brain Diabetes mellitus (ˌdaɪəˈbiːtiːz or /ˌdaɪəˈbiːtəs/ /məˈlaɪtəs/ or /ˈmɛlətəs/ often referred to simply as diabetes ( Ancient Greek: grc Coronary disease (or coronary heart disease) refers to the failure of Coronary circulation to supply adequate circulation to Cardiac muscle and surrounding ^[18] Other research supports the idea that a high egg intake increases cardiovascular risk in diabetic patients. ^[19] However, some "no correlation" findings have come under attack by independent observers for flawed methodology and financial ties to the egg industry. ^[20]

Contamination

A health issue associated with eggs is contamination by pathogenic bacteria like Salmonella enteritidis. A pathogen (from Greek πάθος pathos "suffering passion" and γἰγνομαι (γεν- gignomai (gen- "I give birth to" infectious The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have Salmonella enterica is a rod shaped Flagellated Gram-negative Bacterium, and a member of the Genus Salmonella Contamination of eggs exiting a female bird via the cloaca may also occur with other members of the Salmonella group, so care must be taken to avoid the egg shell becoming contaminated with fecal matter. In zoological anatomy a cloaca is the posterior opening that serves as the only such opening for the intestinal and urinary tracts of certain animal species Feces, faeces, or fæces (see spelling differences) is a waste product from an animal's digestive tract expelled through the Anus In commercial practice, eggs are quickly washed with a sanitizing solution within minutes of being laid. The risk of infection from raw or undercooked eggs is dependent in part upon the sanitary conditions under which the hens are kept.

Health experts advise people to refrigerate eggs, use them within two weeks, cook them thoroughly, and never consume raw eggs [1]. As with meat, containers and surfaces that have been used to process raw eggs should not come in contact with ready-to-eat food. In modern English usage meat most often refers to Animal tissue used as food mostly Skeletal muscle and associated Fat, but it may also refer

A study by the U. S. Department of Agriculture in 2002 (Risk Analysis April 2002 22(2):203-18) suggests the problem is not as prevalent as once thought. It showed that of the 69 billion eggs produced annually, only 2. 3 million of them are contaminated with salmonella - equivalent to just one in every 30,000 eggs - thus showing that salmonella infection is quite rarely induced by eggs. However, this has not been the case in other countries where Salmonella enteritidis and Salmonella typhimurium infections due to egg consumptions are major concerns ^{[21], [22], [23]}. Salmonella enterica is a rod shaped Flagellated Gram-negative Bacterium, and a member of the Genus Salmonella Salmonella enterica is a rod shaped Flagellated Gram-negative Bacterium, and a member of the Genus Salmonella

Egg shells act as hermetic seals which guard against bacteria entering, but this seal can be broken through improper handling or if laid by unhealthy chickens. A hermetic seal is a seal which for practical purposes is considered airtight Most forms of contamination enter through such weaknesses in the shell.

Food allergy

One of the most common food allergies in infants is eggs. A food allergy is an adverse immune response to a food protein ^[24] Infants usually have the opportunity to grow out of this allergy during childhood, if exposure is minimized. Generally, physicians will recommend feeding only the yolks to infants because of the higher risk of allergic reaction to the egg white. Allergy is a disorder of the Immune system often also referred to as Atopy.

The egg allergy is prevalent enough in the United States that food labeling practices now include eggs, egg products and the processing of foods on equipment that also process foods containing eggs in a special allergen alert section of the ingredients on the labels.

Chicken egg sizes

Chicken eggs are graded by size, for the purpose of sales. The United States Department of Agriculture grades them by weight per dozen. The most common US size of chicken egg is 'Large' and is the egg size commonly referred to for recipes. The following egg masses have been calculated on the basis of the USDA grades:

In Europe, modern egg sizes are defined as follows:

In Australia, the Australian Egg Corporation defines the following sizes in its labelling guide. The Australian Egg Corporation Limited ( Australian Egg Corporation) is the major marketer of eggs in Australia ^[25]

In Western Australia, two additional sizes are also standardized by the Golden Eggs Corporation^[26]

In New Zealand sizes are based on the minimum mass per egg: ^[27]

Issues in mass production

Main article: Battery cage

Commercial factory farming operations often involve raising the hens in small crowded cages, preventing the chickens from engaging in natural behaviors such as wing-flapping, dust-bathing, scratching, pecking, perching and nest-building. Western Australia is a state occupying the entire western third of the Australian continent. New Zealand is an Island country in the south-western Pacific Ocean comprising two main landmasses (the North Island and the South Island For other uses of the words gram or gramme see Gram (disambiguation. In Industrial agriculture, battery cages (called laying cages in the United States are a confinement system used primarily for egg-laying hens. Factory farming is the practice of raising Farm animals in confinement at high stocking density where a farm operates as a Factory &mdash a practice typical in Such restrictions can lead to pacing and escape behavior. Escape response, escape reaction, or escape behaviour is a possible reaction in response to stimuli indicative of danger in particular it initiates ^[28]

Many hens confined to battery cages, and some raised in cage-free conditions, are de-beaked to prevent harming each other and cannibalism. Debeaking, also called beak trimming is the partial removal of the Beak of Poultry, especially Chickens and Turkeys Most commonly Cannibalism (from Spanish es ''caníbal'' in connection with cannibalism among the Antillean Caribs, also called anthropophagy (from Greek ἄνθρωπος According to critics of the practice, this can cause hens severe pain to the point where some may refuse to eat and starve to death. Some hens may be force molted to increase egg quality and production level after the molting. Induced molting (or forced molting) is the practice by the commercial egg industry of artificially provoking a complete flock of hen to molt simultaneously ^[29] Molting can be induced by extended feed withdrawal, water withdrawal or controlled lighting programs.

Laying hens are often slaughtered between 100 - 130 weeks of age when their egg productivity starts to decline. ^[30] Due to modern selective breeding, laying hen strains differ from meat production strains. This article focuses on selective breeding in domesticated animals In biology strain is a low-level Taxonomic rank used in three related ways As male birds of the laying strain do not lay eggs and are not suitable for meat production, they are generally culled at the hatchery. ^[31]

Free-range eggs are considered by some advocates to be an acceptable substitute to factory farmed eggs. The main difference between Free range and factory farmed eggs is that the birds are permitted to roam freely within the farmyard and only kept in Sheds or Henhouses Free range laying hens are given outdoor access instead of being contained in crowded cages. Free range is a method of Farming Husbandry where the Animals are allowed to roam freely instead of being contained in any manner Questions on the actual living conditions of free range hens have been raised as there is no legal definition or regulations for eggs labeled as free range in the US. ^[32]

In the US, increased public concern for animal welfare has pushed various egg producers to release eggs under a variety of different standards. Animal welfare refers to the viewpoint that it is morally acceptable for humans to use nonhuman animals for food in animal research, as clothing and in entertainment The most widespread standard in use is used by United Egg Producers and is a volunteer program known as United Egg Producers Certified(UEP Certified). ^[33] The program includes guidelines with regard to housing, feed, water, air, space allowance, beak trimming, molting, handling, and transportation; however, critics such as The Humane Society have alleged UEP Certification misleadingly allows for a significant amount of animal cruelty. A humane society may be a group that aims to stop human or animal Suffering due to Cruelty or other reasons although in many countries it is now used mostly for societies ^[34] Other standards include "Cage Free", "Natural", "Certified Humane", and "Certified Organic. " Of these standards, "Certified Humane", which carries requirements for stocking density and cage-free keeping, among others, and "Certified Organic", which requires hens have outdoor access and are fed only organic, vegetarian feed, among other requirements, are the most stringent. ^{[35] [36]}

Cultural influences

Main articles: Egg decorating, Easter egg, and Egging

Hanácké kraslice, Easter eggs from the Haná region, the Czech Republic

A popular Easter tradition in some parts of the world is the decoration of hard-boiled eggs (usually by dyeing but often by spray-painting). Egg decorating is the art or craft of decorating eggs It is quite a popular art/craft form because of the attractive smooth oval shape of the egg Egging refers to the act of throwing Eggs at houses cars or people The Czech Republic ( ˈt͡ʃɛskaː ˈrɛpuˌblɪka short form in Česko ˈt͡ʃɛskɔ also called Czechia, Easter ( Greek: Πάσχα Pascha or Pasxa) is the most important religious feast in the Christian Liturgical year. Adults often hide the eggs for children to find, an activity known as an Easter egg hunt. A similar tradition of egg painting exists in areas of the world influenced by the culture of Persia. Egg decorating is the art or craft of decorating eggs It is quite a popular art/craft form because of the attractive smooth oval shape of the egg The Persian Empire was a series of Iranian empires that ruled over the Iranian plateau, the original Persian homeland and beyond in Western Asia Before the spring equinox in the Persian New Year tradition (called Norouz), each family member decorates a hard-boiled egg and sets them together in a bowl. An equinox is the event of the Sun passing over the Earth's equator in its annual cycle Nowrūz ( /noruz/ ↔, (English New Day various local pronunciations and spellings) is the traditional Iranian New year Holiday celebrated

Although a food item, eggs are sometimes thrown at houses, cars, or people generally on Halloween. Halloween, or Hallowe’en, is a Holiday celebrated on the night of October 31. This act, known commonly as egging in the various English-speaking countries, is a minor form of vandalism and, therefore, usually a criminal offense and is capable of damaging property (egg whites can degrade certain types of vehicle paint) as well as causing serious eye injury^[37]. Egging refers to the act of throwing Eggs at houses cars or people The following is a list of Sovereign states and territories where English is an Official language, in order of Population. Vandalism is the behaviour attributed to the Vandals in respect of Culture: ruthless Destruction or spoiling of anything beautiful or Venerable In the sociological field, crime is the breach of a rule or Law for which some governing authority or force may ultimately prescribe a Punishment On Halloween, for example, trick or treaters have been known to throw eggs (and sometimes flour) at property or people from whom they received nothing. Halloween, or Hallowe’en, is a Holiday celebrated on the night of October 31. Eggs are also often thrown in protests, as they are inexpensive and nonlethal, yet at the same time very messy when broken.

Notes and references

External links

• Nutritional values of eggs
• Nutritional value of free range eggs compared with factory eggs
• Criticism of the validity of the "Animal Care Certified" logo used by United Egg Producers(UEP)
• British Egg Industry and the Lion Mark
• Henderson's Chicken Breed Chart
• Fact Sheet on FDA's Proposed Regulation: Prevention of Salmonella Enteritidis in Shell Eggs During Production
• Hatching Quail Eggs In A Classroom