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All About the Egg


While the most familiar egg package is the pulp or foam carton holding one dozen eggs, eggs are now being packed in more different package sizes than ever before. In some regions, cartons or other packs of 6, 8, 12, 18, 30, 36 or 60 eggs are available, making it easy to buy eggs for households of almost any size. To maintain quality, buy only as many eggs as you will use within three to four weeks.

Whether made of pulp, foam or clear plastic, the carton insulates the eggs from jolts. New package designs are constantly being tested to provide the best protection for the eggs. The carton also prevents loss of moisture and carbon dioxide from the eggs and keeps the eggs from picking up undesirable odors and flavors. Because temperatures fluctuate more on the refrigerator door and slamming can cause breakage, it’s best to store eggs in their carton on a middle or lower inside shelf.

Packing machines place eggs in their cartons large end up to keep the air cells in place and the yolks centered.

The carton shows brand, grade, egg size and nutrient content.

Pain Perdu

– See French Toast

Partnership For Food Safety Education

Composed of government agencies, organizations such as American Egg Board, and other nonprofit groups, the Partnership works to educate consumers on the proper handling of foods to prevent foodborne illness.

The Be Food Safe and Fight Bac! programs of the Partnership are based on four simple steps:


Wash hands and surfaces often.


Don’t cross-contaminate.


Cook to proper temperatures.


Refrigerate promptly.

– See Cooking Methods, Doneness Guidelines, Egg Safety, Fight BAC!, Raw Eggs, Salmonella

Pasteurized Eggs

Eggs that have been exposed to heat in order to destroy potential bacteria. Due to the heat process, pasteurized eggs may have slightly lower amounts of heat-sensitive vitamins, such as riboflavin, thiamin and folic acid.

Along with updating recipes to cook them properly — using pasteurized egg products and shell eggs is an option for safely preparing recipes calling for raw or undercooked eggs. Although the rate of egg contamination with Salmonella bacteria is only about 1 in 20,000 eggs, it’s best to choose one of these options when you make raw or only partially cooked recipes – especially when you serve the very young, the elderly, pregnant women or anyone whose immune system is impaired.

Pasteurized shell eggs are especially suitable for preparing egg recipes that aren’t fully cooked, but you can also use them for other recipes, too, including baked goods. The heating process may create cloudiness in the whites and increase the time you need to beat the whites for foam formation. Allow up to about four times as much time for full foam formation to occur in pasteurized egg whites as you would for the whites of regular eggs. Prepare other recipes as usual.

Pasteurized shell eggs must be kept refrigerated. You can store them for at least 30 days from the pack date.

Pasture-Fed Hens

– See Free-Range Eggs


– See Hard or Swiss Meringue


Removing the shell and membranes from a hard-boiled egg.

Opinion among researchers is divided as to whether or not salt in the cooking water helps make hard-boiled eggs easier to peel. Some research indicates that a 1 to 10% salt level (2 to 4 tablespoons per gallon of water) makes unoiled eggs easier to peel, but peelability of oiled eggs is not significantly affected. About 90% of the eggs available at retail are unoiled.

A nicely centered yolk makes very attractive deviled eggs and garnishes. However, as an egg ages, the white thins out which gives the yolk more opportunity to move about freely. This can result in a displaced yolk when you cook the egg. Using the freshest eggs possible will minimize this displacement, but very fresh eggs are more difficult to peel after hard boiling.

The air cell that forms between the shell membranes as the egg ages helps to separate shell from egg but, in very fresh eggs, the air cell is still small. The best compromise for attractive eggs with centered yolks that are relatively easy to peel seems to be using eggs that have been refrigerated for about a week to 10 days. Some new research suggests that yolk centering may be better if you store eggs small-end up for 24 hours before hard-boiling. Immediately after cooking, thoroughly cool eggs in a bowl of ice or under running cold water; five minutes isn’t too long. Peel the eggs right after cooling for immediate use or refrigerate them in the shell in the carton for use within one week. To peel an egg, crackle the shell all over by gently tapping the egg on a table or countertop.

Roll the egg between your hands to loosen the shell. Then peel off the shell, starting at the large end. Hold the egg under running water or dip it in water to make peeling easier.
– See Air Cell; Composition; Cooking Equipment, Piercer; Cooking Methods, Hard-Boiled


Pet Food

Eggs are often an important part of prepared pet-food formulas. Some pet owners also feed eggs to their pets as treats or prepare home-cooked pet food using eggs.

Pickled Eggs

Hard-boiled eggs marinated in vinegar and pickling spices, spicy cider, or juice from pickles or pickled beets.

Unopened containers of commercially pickled eggs keep for several months on the shelf (see specific product for details). After opening, keep refrigerated and use within seven days. Home-prepared pickled eggs must be kept refrigerated and used within seven days. Home canning of pickled eggs is not recommended. Although the acidity of the pickling solution is usually sufficient to prevent the growth of bacteria, it eventually causes the eggs to disintegrate.
– See Cooking Methods, Hard-Boiled; Peeling

Poached Eggs

- See Cooking Methods, Poached


An egg-rich, hollow bread baked in small cups or pans. A very hot oven creates the steam inside the batter that pops the individual breads to magnificent heights.

Pot de Crème

– See Custard-Baked



Refrigeration, drying or freezing are the best ways to preserve egg quality. Fresh eggs are so readily available that long storage periods are rarely necessary. However, centuries before modern methods of egg production, transportation and refrigeration became known, people did their ingenious best to preserve the egg intact.

The ancient Chinese stored eggs up to several years by immersion in a variety of such imaginative mixtures as salt and wet clay; cooked rice, salt and lime; or salt and wood ashes mixed with a tea infusion. Although the Chinese ate them with no ill effects of which we are aware, the eggs thus treated bore little similarity to fresh eggs, some exhibiting greenish- gray yolks and albumen resembling brown jelly.

Immersion in different liquids too numerous to mention was explored, lime water being a favorite in the 18th century. During the early 20th century, water glass was used with considerable success. Water glass, a bacteria-resistant solution of sodium silicate, discouraged the entrance of spoilage organisms and evaporation of water from eggs. It didn’t penetrate the eggshell, imparted no odor or taste to the eggs and was considered to have somewhat antiseptic properties. However, it did a rather poor job at relatively high storage temperatures. Eggs preserved in a water-glass solution and stored in a cool place keep 8 to 9 months.

Dry packing in various substances ranging from bran to wood ashes was used occasionally, but costs of transporting the excess weight of the packing material far exceeded the dubious advantages.

In an attempt to seal the shell pores to prevent loss of moisture and carbon dioxide, a great variety of materials including cactus juice, soap and shellac were investigated with varying degrees of success. The only coating considered fairly efficient was oil, which still is used occasionally today.

Thermostabilization, immersion of the egg for a short time in boiling water to coagulate a thin film of albumen immediately beneath the shell membrane, was rather extensively practiced by housewives of the late 19th century. Mild heating destroyed spoilage organisms but didn’t cook the eggs. If kept in a cool place, thermostabilized eggs coated with oil keep several months, although some mold growth may take place.

During the first half of the 20th century, storing eggs in refrigerated warehouses was a common practice. Preservation was later improved with the introduction of carbon dioxide into the cold storage atmosphere. Today, very few, if any, cold storage eggs find their way to the retail market.
– See Cold Storage, Oiling

Price Per Pound

An easy way to compare the price of eggs with other protein foods.
– See Buying


Egg Production during the year ending November 30, 2011 totaled 91.9 billion eggs, up slightly from 2010. Table egg production, at 79.0 billion eggs, was up 1 percent from the previous year.


Maximum production of top-quality eggs starts with a closely controlled breeding program emphasizing favorable genetic factors. The Single-Comb White Leghorn hen dominates today’s egg industry. This breed reaches maturity early, utilizes its feed efficiently, has a relatively small body size, adapts well to different climates and produces a relatively large number of white-shelled eggs, the color preferred by most consumers. Brown-shelled eggs are now available in most markets, but have long been the traditional favorite in the New England region. Commercial brown-egg layers are hens derived from the Rhode Island Red, New Hampshire and Plymouth Rock breeds which predominated in that area of the country.
 – See Color, shell

Resistance to Disease

Selective breeding is reinforced by good sanitation and vaccination.


Light Control

Of primary importance during both the growing and laying periods, controlled, low-intensity light can be used in house systems to delay sexual maturity until the bird’s body is big enough to produce larger eggs. Intensity and duration of light can be adjusted to regulate production.


Laying houses maintained between 57° and 79ºF (14° and 26ºC) are desirable.


A relative humidity between 40 and 60% is optimal.

Housing Systems 

America’s egg farmers are committed to producing a fresh, high-quality product and therefore are committed to the health and well-being of their hens. Housing systems today vary, but all ensure the hens are provided with adequate space, nutritious feed, clean water, light and fresh air. America’s egg farmers produce eggs from multiple production systems conventional, cage-free, free-range, and enriched colony. All organic systems are free-range.

 Conventional: Eggs laid by hens living in cages with access to feed, water, and security. The cages serve as nesting space as well as for production efficiency. In this type of hen house, the birds are more readily protected from the elements, from disease and from natural and unnatural predators.

Cage-free: Eggs laid by hens at indoor floor operations, sometimes called free-roaming. The hens may roam in a building, room or open area, usually in a barn or poultry house, and have unlimited access to fresh food and water, while some may also forage for food if they are allowed outdoors. Cage-free systems vary and include barn-raised and free-range hens, both of which have shelter that helps protect against predators. Both types are produced under common handling and care practices, which provide floor space, nest space and perches. Depending on the farm, these housing systems may or may not have an automated egg collection system. 

Free-range: Eggs produced by hens that have access to outdoors in accordance with weather, environmental or state laws. In addition to consuming a diet of grains, these hens may forage for wild plants and insects and are sometimes called pasture-fed hens. They are provided floor space, nesting space and perches.

Organic: Eggs produced according to national U.S. Department of Agriculture organic standards related to methods, practices and substances used in producing and handling crops, livestock and processed agricultural products. Organic eggs are produced by hens fed rations having ingredients that were grown without most conventional pesticides, fungicides, herbicides or commercial fertilizers. 

Enriched Colony: A production system that contains adequate environmental enrichments to provide perch space, dust bathing or a scratch area(s), and nest space to allow the layers to exhibit inherent behavior. Enriched colony systems are American Humane Certified.


Since more is known about the nutritional requirements of the chicken than of any other domestic animal, feed rations are scientifically balanced to assure layer health along with optimum quality eggs at least cost. Automatic feeders, activated by a time clock, move feed through troughs that allow for feeding ad libitum. Birds are also provided water at all times via nipple valves separate from the feed troughs.

Poultry rations are designed to contain all the protein, energy (carbohydrates), vitamins, minerals, and other nutrients required for proper growth egg production, and health of the layer hen. Feed might be based on sorghum, grains, corn, cottonseed meal or soybean meal, depending on the part of the country in which the ration is produced and which ingredient is most available and cost effective. The hen’s ration may contain the same types of additives approved for human food. Antioxidants or mold inhibitors (also used in mayonnaise and bread) are added to maintain the quality of the feed. An additive is not approved for use in poultry feed unless adequate research has been undertaken to determine its pharmacological properties and possible toxicity and to discover any potentially harmful effects on animals.

Federal regulations prohibit the feeding of hormones to any kind of poultry in the U.S. Antibiotics are only rarely used when chickens are ill, at which time they seldom lay eggs. If antibiotics are used, FDA regulations require a withdrawal period for laying hens to ensure eggs are free of antibiotics.

How much a layer eats depends upon the stage of life, the hen’s size, the rate of egg production, temperature in the laying house and the energy level of the feed. In general, about 4 pounds of feed are required to produce a dozen eggs. A Leghorn chicken eats about 1/4 pound of feed per day. Layers of brown-shelled eggs are slightly larger and require more feed.

The type of feed affects egg quality. Shell strength, for example, is determined by the presence and amounts of vitamin D, calcium and other minerals in the feed. Too little vitamin A can result in blood spots. Yolk color is influenced by yellow-orange plant pigments in the feed. Maximum egg size requires an adequate amount of protein and essential fatty acids.

Flock Management 

Molting, or loss of feathers, is a natural occurrence common to all birds regardless of species. In the wild, egg quality declines as the hen ages and, at about 18 to 20 months of age, molting occurs and egg production ceases. In conventional egg production, a fairly common practice is to place the flock into a controlled molt. A low-protein diet minimizes stress on the birds as they go through this transition period. After a rest period of 4 to 8 weeks, the birds start producing eggs again. Researchers have found that two periods of controlled molting, one at 14 months and another at 22 months, increases egg production more than one molt at 18 or 20 months, though few egg farmers place flocks into two controlled molts. Controlled molting is not permitted in organic flocks, though natural mottling can occur.

Egg Handling

In most commercial egg production facilities, automated belts gather eggs every day. Gathered eggs are moved into refrigerated holding rooms where temperatures are maintained between 40° and 45ºF (4º and 7ºC).
 – See Cleaning

Egg Processing and Distribution

Some producers sell their eggs nest-run (ungraded) to processing firms which clean, grade, size and carton the eggs and ship them off to retail outlets. Most farms and ranches carry out the entire operation.
– See Egg Products, Egg Products Inspection Act, Grading, Nest-Run Eggs


–See Cream Puffs


A combination of amino acids, some of which are called essential, meaning the human body needs them from the diet because it can’t synthesize them. Adequate dietary protein intake must include all the essential amino acids your body needs daily. The egg boasts them all: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. These amino acids are present in a pattern that matches very closely the pattern the human body needs, so the egg is often the measuring stick by which other protein foods are measured. In addition to the nine essential amino acids, there are nine other amino acids in an egg.

Many different ways to measure protein quality have been developed. According to the Protein Digestibility Corrected Amino Acid Score (PDCAAS), whole egg, whey protein, casein and soy-protein concentrate all score 1 on a scale of 0 to 1. Whole egg exceeds all other protein foods tested with a score of 1.21 (above human needs) in the Amino Acid Score (AAS) rating system. At 3.8, the Protein Efficiency Ratio (PER) of eggs also outscores other proteins. When Nitrogen Protein Utilization (NPU) is evaluated, whole egg at 98% falls just below whey protein and casein (both at 99%). On a scale with 100 representing top efficiency, the Biological Value (BV) of eggs is rated between 88 and 100, with only whey protein rated higher (100).

Altogether each large egg provides a total of 6.29 grams of high-quality, complete protein. For this reason, eggs are classified with meat in the Protein Foods Group. One egg of any size equals one ounce of lean meat, poultry, fish or seafood. In addition to about 12.6% of the Daily Reference Value (DRV) for protein, a large egg provides varying amounts of many other nutrients, too.
– See Biological Value, Buying, Daily Reference Values (DRVs), Food Guide Pyramid, Meat Replacement, Nutrient, Density


A young female chicken less than 1 year old. For egg layers, a pullet is a young female before she reaches sexual maturity and starts laying eggs, around 17-18 weeks.


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