Eggs: A Consumer Guide

Purchase only clean, unbroken, odor-free eggs. Quality is indicated by egg grade, not size. A process called candling, in which eggs are held in front of a light source, allows egg graders and inspectors to observe the size of the air pocket (an indicator of quality and age), the condition of the yolk and the white, and any hidden defects. These factors, along with shell soundness, cleanliness and shape, are used to classify eggs as Grade AA, Grade A or Grade B. ​AA and A are the grades most commonly marketed at retail. Grade AA eggs are the highest quality, but there is no difference in nutritive value among the different grades.

The official size or weight classes are:

For accurate price comparison when purchasing eggs, compare different sizes of the same grade.

All eggs sold at retail must be prepackaged in new cartons. Labels must include the grade, size, candling date, and name and address of the packer, distributor or retail store. Although not required by law, operators are encouraged to stamp cartons with a date by which eggs should be sold, (See Egg Carton Labeling Terms for more information).

The candling, or Julian, date is a three-digit number indicating the specific day of the year on which the eggs were graded, sized and packed. For example, the number 001 would represent Jan. 1, while 365 would be Dec. 31. This number provides an indication of the eggs' freshness.

Eggs cannot be sold at retail more than 45 days after the candling date. To prevent eggs from being sold beyond this time frame, many packers mark cartons with a "sell by" date. The "sell by" date, also called the expiration date, must not exceed 45 days after the candling date. After the expiration date has passed, unsold eggs are returned to the supplier where they may be recertified by trained graders or shipped to egg breaking plants for processing into liquid, frozen or dried eggs.

Yes. "Sell by" or expiration codes indicate freshness, not necessarily wholesomeness. Since egg quality deteriorates over time, "sell by" dates are used to ensure the grade specified on the label is accurate. If stored properly, eggs may be safely consumed several weeks beyond the expiration date.

Yes. Eggs contain 13 vitamins and numerous minerals. One egg provides 10 to 13 percent of the daily reference value for protein--as much as one ounce of lean meat, fish or poultry. Egg protein is the highest quality food protein--second only to mother's milk for human nutrition.

Eggs are nutrient-dense; they provide many nutrients compared to the number of calories they contain. The following chart lists the calorie count for different sizes.

One large egg contains about 4.5 grams of fat, but only 1.5 grams of saturated fat, the kind linked to increased blood cholesterol levels. More than half the egg's total protein content is found in the egg white, which is both fat- and cholesterol-free.

No. Shell color depends on the breed of hen that produced the egg. It does not affect the egg's nutritive value, cooking properties, flavor or quality.

When eggs are cooked for too long or at too high a temperature, they will sometimes turn green. Color change may also occur if the cooking water contains a high level of iron. Although the green tint does not affect flavor or wholesomeness, it may be avoided by cooking at low temperatures and using stainless steel equipment.

Yes. The presence of blood spots on the yolk does not mean the egg is fertilized or unfit to eat. Blood spots occur occasionally when a blood vessel on the yolk sac surface ruptures during egg formation. Easily removed with the tip of a knife, the spots do not affect the egg's nutritive or chemical properties.

Salmonella refers to a type of bacteria that may lead to food poisoning in humans and animals. Eggs, as well as other foods, are susceptible to bacterial growth. However, eggs have several natural barriers that help prevent contamination, such as the shell, enzymes found in the egg white and membranes surrounding the shell and yolk.

Observing the following precautions will help prevent salmonella food poisoning:

• Use only fresh, clean, unbroken, properly refrigerated eggs.
• Avoid mixing yolks and whites with the shell.
• Refrigerate eggs and egg dishes if you do not plan to eat them within an hour.
• Keep cold egg dishes at temperatures below 41 degrees and hot egg dishes above 140 degrees.
• Use homemade eggnog and ice-cream recipes based on cooked, stirred custard.
• Keep hands and utensils clean when cooking.
• Wash hands before and after handling raw poultry products.

Agriculture Department officials conduct annual inspections of about 10,000 businesses that sell, grade, pack or serve eggs and more than 1,000 facilities that traffic large quantities of eggs to wholesalers or retailers. All people who market eggs commercially must be licensed by the Agriculture Department unless they are producers who only sell eggs for personal use.

Agriculture Department inspectors visit supermarkets and other retail outlets to ensure eggs are kept in a sanitary environment, are adequately refrigerated, are whole and undamaged, and meet the grade, weight and date specified on the carton.

People who suspect an Illinois grocery store or other egg outlet is not upholding the law should talk to the facility manager. If the problem persists, they should call the Illinois Department of Agriculture at 1.800.582.0468, TDD 866.287.2999, FAX 217.524.7801 or email at agr.eggs@illinois.gov​

• Leave eggs in their original carton to help prevent them from drying out.
• Store eggs at 41 degrees with the small end of the shell pointed down in the carton.
• Keep eggs away from foods with strong odors, such as onions and garlic, which can affect their flavor.
• Do not store eggs for an extended period of time.