Go Here Test

More Diets

Go Here Test


Eggs: Main Image

Buying Tips

The freshness of the eggs you buy reflects both how recently they were laid and the temperature at which they were stored. Ideally, eggs should be stored at 40°F (4°C) or below, and at a relative humidity of 70 to 80 percent. To avoid food poisoning from Salmonella bacteria, it is important that you buy only eggs that have been well refrigerated. Before purchasing, open the carton and make sure none of the eggs are cracked; if you discover cracked eggs at home, discard them, since bacteria may have contaminated the egg. To determine the freshness of eggs when shopping, test the weight—the heavier the egg, the fresher it is. Air builds up inside the egg as it ages; this pocket of air is the reason hard-boiled eggs are flattened at one end. If you hold a white egg up to the light, you will be able to see the air pocket (brown eggs are too dark for the air pocket to be visible). When eggs are graded, Grade AA eggs may not contain an air cell that exceeds 1/8-inch in depth. The air cell of Grade A eggs may be 3/16 or greater. Grade B eggs have no requirements regarding the air cell. When reviewing dates on the egg carton, note that those packed in plants that are inspected by the USDA display the date they were packed, written as a Julian date, numbering from 1 to 365 to reflect the day of the year (for example, December 29 would be 363). The U.S. Food and Drug Administration (FDA) suggests that eggs can be used up to four weeks from the time they are packed without loss of nutritional quality. The cartons also often carry an expiration date beyond which the eggs should not be sold.



The U.S. Department of Agriculture (USDA) and state governments provide inspection and grading. Grade AA and A eggs are defined as eggs that hold their shape well, with tall yolks and thick egg whites. The chalaza is prominent, another sign of freshness. Grade B eggs may have flattened yolks and the white tends to be thinner; typically these eggs are used by food manufacturers, bakers, and institutions.


The size of the egg is a reflection of the age, weight, and breed of the hen, with mature hens producing larger eggs. Environmental factors that lower the weight of an egg include heat, stress, overcrowding, and poor nutrition. Specific egg sizes are classified according to weight, expressed in ounces per dozen. Most recipes for baked dishes, such as custards and cakes, are based on the use of “Large” eggs.

Battery eggs

This term refers to eggs laid by chickens that are permanently caged. Although they are not required to be labeled as such, eggs are from battery-raised hens unless labeling indicates otherwise.

Brown vs. white

The color of the egg’s shell is a reflection of the breed of hen. Breeds with white feathers and ear lobes, such as White Leghorns, lay white eggs. Those with red feathers or ear lobes lay brown eggs. White eggs are in high demand among most American buyers, but in certain parts of the country, particularly New England, brown shells are preferred. Breeds that lay brown eggs include the Rhode Island Red, New Hampshire, and Plymouth Rock varieties.

Duck eggs

Duck eggs are larger than those laid by chickens, and have a higher fat content. The white tends to be more gelatinous, and the yolks are a brighter yellow. Physical characteristics of the yolk reflect both the duck’s diet and the egg’s freshness. In some cases the duck egg has a stronger flavor than a chicken’s egg. Scrambled or in omelets, duck eggs are well complemented by onions, peppers, mushrooms, or cheeses. Cooks accustomed to using duck eggs use them much like chicken eggs, taking into account their larger size. Some combine duck and chicken eggs to achieve the consistency they want in particular dishes. Professional bakers are said to prefer duck eggs because of their rich yolks and because the baked goods have better texture and hold their shape better. In Asian cuisine, duck eggs are sometimes pickled or preserved to make what are called “Thousand-Year-Old-Eggs.” Some people who are allergic to chicken eggs are able to tolerate duck eggs. Duck eggs are difficult to obtain and may be available only through specialty shops, Asian grocery stores, or by special order.

Fertile eggs

These eggs are laid by hens regularly exposed to a rooster.

Free-range eggs

Eggs labeled “free range” are laid by uncaged chickens that are permitted to exercise and move about. Under genuine free-range conditions, hens are raised outdoors or have daily access to the outside. Some egg farms are described as indoor-floor operations; in this type of environment, the hens are raised indoors, but have some freedom of movement.

Ostrich eggs

The ostrich egg is said to have been a favorite food of Queen Victoria. Each egg contains the equivalent of about two dozen chickens’ eggs. An ostrich egg weighs about 3 pounds (1,360g); it would take roughly 40 minutes to hard-boil an ostrich egg.

Quail eggs

Gourmets report that quail eggs are among the most delicious in the world. The eggs are small and fine (about 1/5 the weight of a chicken’s egg), with richly speckled shells that range in color from dark brown to blue or white. The nutritional content is comparable to that of chicken eggs, with flavor that is comparable or perhaps more delicate. Quail eggs are associated with gourmet cuisine. Some people who are allergic to chicken eggs find that they can tolerate quail eggs.

Copyright © 2024 TraceGains, Inc. All rights reserved.

Learn more about TraceGains, the company.

The information presented in the Food Guide is for informational purposes only and was created by a team of US–registered dietitians and food experts. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements, making dietary changes, or before making any changes in prescribed medications. Information expires December 2024.