Just Wondering . . .

Purchasing eggs:

1) Is there a nutritional difference between brown eggs and white eggs?

Brown and white eggs have the same nutritional value. Shell color is representative of the breed of hen that produces the egg. White hens produce white eggs and brown hens produce brown eggs. Generally, brown hens are larger and require more feed and therefore their eggs may be slightly higher priced.

2) What is the difference between graded shell eggs bearing the USDA shield and :

The organic/vegetarian egg: Eggs that are labeled organic and have the USDA organic seal on the carton were produced following the USDA National Organic Program. Vegetarian eggs are produced by hens whose feed is free of animal by-products.

A nutrient enhanced egg: Additional nutrients have been added to the feed of the hen in an effort to enrich the nutrient profile of the egg. Nutrient enhanced eggs may have higher levels of a specific nutrient such as omega-3 fatty acid, vitamin E or lutein than the generic shell egg.

The cage free egg: Most hens are housed in large laying facilities that use cage systems. This provides hens with optimal temperature, humidity, feed and water as well as safety. It is designed for the welfare of the bird as well as for production efficiency.

Consumers who object to the cage system of egg production can choose either cage free or free range eggs.

The United Egg Producers Certified Egg: Egg producers have begun voluntarily implementing animal welfare standards that improve the care and handling of egg laying hens. These standards were developed by an independent scientific advisory committee consisting of scientists from governmental agencies, academia and the US Humane Association. For more information see: www.uepcertified.com

The USDA A or AA shield certifies that a representative sample of these eggs have been examined by a US Department of Agriculture grader for quality and size. For further information see www.ams.usda.gov/poultry

3) What does the date on the egg carton mean?

Egg cartons with the USDA grademark must display a “Julian date”*, the date the eggs were packed. Although not required, they may also carry an expiration date beyond which the eggs should not be sold, but are still safe to eat. On cartons with the USDA grademark, this date can not exceed 30 days after the eggs were packed in the carton. Depending on the retailer, the expiration date may be less than 30 days. Eggs packed in cartons without the USDA grademark are governed by the laws of their states.

*Julian date: usually on the short side of the carton, represents the consecutive days of the year with the number 001 as January 1 and December 31 as 365.

4) How long are eggs safe to eat after purchase?

Fresh shell eggs can be stored in their cartons in the refrigerator for four to five weeks beyond the carton’s Julian date with minor loss of quality. Once an egg begins to age, it loses moisture through its porous shell and begins to dry. The membranes that hold the egg structure begin to loosen and the yolk may not be anchored in the center of the white once the egg is broken. An older egg would be most appropriate for a mixed dish, a batter or a hard cooked egg which should be easier to peel than a freshly laid egg.

5) Why do some eggs have dark yellow yolks and some have light yellow?

The color of the egg yolk is dependent upon the feed of the hen. A diet of wheat and white corn meal would produce an almost colorless yolk. If however the hen was fed a diet that includes yellow corn meal and/or marigolds the egg yolk would have a deep yellow color, generally preferred in the US.


2. Caring for eggs:

1) What’s the best way to store eggs?

Eggs should be refrigerated at 40°F to maintain food safety. An egg can age the equivalent of several days if held at room temperature. The best place for the egg is in its carton on an inside refrigerator shelf. Regardless of whether the carton is made of styrofoam or cardboard, the carton will insulate the egg from damage and loss of moisture. It is not advisable to store eggs in the refrigerator door since it subjects the egg to variable temperatures and possible breakage.

2) What should I do if I left my eggs in the car overnight?

Although the temperature of the car may be cool overnight, the exposure to warmer temperatures during the day may make it unsafe to eat. If the eggs have been exposed to temperatures above 40°F for more than 2 hours, they should be discarded. According to USDA food safety advice, “A cold egg left out at room temperature can sweat, facilitating the growth of bacteria. Refrigerated eggs should not be left out more than 2 hours.

3) How long are eggs that have been refrigerated, safe to eat? Raw eggs maintain their freshness for 4-5 weeks after purchase if kept refrigerated continuously.

4) Is testing an egg for freshness by seeing if it floats in a glass of water a good test?

Possibly. As an egg ages it loses moisture through its shell. This decreases the weight of the egg while the volume of the shell doesn’t change. This moisture loss is replaced with air producing an increasing large air sac as the egg ages. The larger the air sac, the lighter the egg. When placed in water, an egg with a large air sac should float while a fresher egg with a smaller air sac should sink. Both eggs would still be safe to eat if cooked thoroughly.

5) How long are hard cooked eggs that have been refrigerated, safe to eat? During the cooking process, some of the egg’s natural defenses are destroyed.

A hard cooked egg can safely be refrigerated for up to one week. 

6) How long can eggs be kept out of the refrigerator after they’ve been cooked?

Like any other naturally high protein food, eggs should only be held at room temperatures (between 70-80°F) for up to 2 hours. If the temperature rises above 80°F, the egg should be refrigerated within 1 hour of exposure to room temperature. Once an egg has been exposed to temperatures higher than 40°F for 2 hours, it must be cooked thoroughly or discarded.

7) Can eggs be frozen?

Fresh eggs can be frozen but must be removed from the shell first, since the water content of the egg will expand when frozen and crack the shell. Separating egg whites from yolks before freezing may be useful for cooking needs.

A useful chart of egg storage times is available at http://www.fsis.usda.gov/Fact_Sheets/Focus_On_Shell_Eggs/index.asp

Egg Storage Chart




Raw eggs in shell

3 to 5 weeks

Do not freeze.

Raw egg whites

2 to 4 days

12 months

Raw egg yolks

2 to 4 days

Yolks do not freeze well.

Raw egg accidentally frozen in shell

Use immediately after thawing.

Keep frozen; then refrigerate to thaw.

Hard-cooked eggs

1 week

Do not freeze.

Egg substitutes, liquid

10 days

Do not freeze.

Egg substitutes, liquid

3 days

Do not freeze.

Egg substitutes, frozen

After thawing, 7 days, or refer to “Use-By” date on carton.

12 months

Egg substitutes, frozen

After thawing, 3 days, or refer to “Use-By” date on carton.

Do not freeze.

Casseroles made with eggs

3 to 4 days

After baking, 2 to 3 months.

Eggnog, commercial

3 to 5 days

6 months

Eggnog, homemade

2 to 4 days

Do not freeze.

Pies, pumpkin or pecan

3 to 4 days

After baking, 1 to 2 months.

Pies, custard and chiffon

3 to 4 days

Do not freeze.

Quiche with any kind of filling

3 to 4 days

After baking, 1 to 2 months.

8) Do eggs cause Salmonella food poisoning?

No, however within the last 20 years eggs have been associated in rare cases with the Salmonella Enteritidis (SE) bacteria. The SE bacteria, has been able to bypass the hen’s natural defenses and live in her reproductive organs. In this case, the entire egg but most likely the yolk could be infected with the Salmonella bacteria. The US Food and Drug Administration estimates that only one in approximately 20,000 eggs produced might be infected with the Salmonella bacteria. Federal and state governments, the egg industry, and the scientific community are working together to solve the problem. Involved government agencies include: USDA’s Food Safety and Inspection Service (FSIS), Agricultural Marketing Service (AMS), and the Animal and Plant Health Inspection Service (APHIS); the U.S. Food and Drug Administration (FDA); and State departments of agriculture.

Government agencies have implemented an Egg Safety Action Plan to eliminate Salmonella Enteritidis illnesses due to eggs. The Action Plan identifies the systems and practices that must be carried out in order to meet the goal of eliminating SE illnesses associated with the consumption of eggs by 2010. The interim goal of the Egg Safety Action Plan is a 50 percent reduction in egg-associated SE illnesses by 2005. Thoroughly cooking your eggs would assure that your eggs are safe to eat.

3. Preparing eggs:

1) Is it okay to let raw eggs come to room temperature before using?

Yes. Eggs can be brought to room temperature within 20-30 minutes to improve their whipping qualities. However, they should be cooked as quickly as possible and should be refrigerated if not cooked within 2 hours.

2) Is it okay to use a cracked raw egg?

No, since the egg shell is one of nature’s protections from infection, discarding any egg whose shell is cracked is recommended.

3) Can you tell a fresh egg from a cooked egg?

You can try spinning an egg (carefully) on a countertop. The cooked egg will spin easily while the raw egg will wobble due to its shifting liquid content.

4) How long should I cook my eggs?

The American Egg Board recommends that hard cooked eggs be placed in cold water and then brought to a boil. Once the water boils, the pot should be covered and removed from the heat and allowed to sit for 15-18 minutes after which time the water should be drained and the eggs cooled in ice water and then refrigerated.

5) Can eggs be microwaved?

Yes, however microwaves are attracted to the fat content of the egg yolk which makes the yolk cook faster than the white. It’s advisable to prick the yolk of an unbeaten egg with a wooden toothpick or the tip of a knife before microwaving. Cook unbeaten eggs at 50% to 30% power. Beaten eggs or foods containing beaten eggs can be cooked at full power. It’s a good idea to cover egg dishes with a lid or plastic wrap to assure more even heating and control any mess.

Note: Eggs in their shells should not be cooked in a microwave due to the lack of ventilation for the steam produced upon cooking. This could result in an explosion which could damage the microwave appliance.

6) Why isn’t it okay to lick the spoon when making cookies, cakes or desserts anymore? What about Caesar salad dressing and homemade eggnog/ice cream/mayonnaise, aren’t they safe if I refrigerate them?

About 20 years ago, a specific strain of Salmonella bacteria became successful at growing in the reproductive organs of the laying hen. In rare cases, estimated to be one in 20,000 eggs, the Salmonella bacteria may infect a shell egg. Due to scientific research and voluntary efforts of egg industry members, egg production is monitored closely and the incidence of Salmonellosis associated with eggs has been substantially diminished. Good home food safety practices which include, vigilant cleaning, thorough cooking, sufficient chilling and separating foods to avoid cross contamination can insure that eggs are always safe to eat.

7) I heard egg whites are better for me if they are raw, it that true?

No, that is not true. In fact, egg whites should not be consumed raw due to food safety concerns. Cooking egg white only changes the structure of the egg protein but there is no loss of quantity or quality.

8) If the eggs are straight from the farm, do they really need to be refrigerated? 

Yes, although eggs that have just been laid are less likely to decay due to spoilage bacteria, they are susceptible to bacterial growth while at room temperature which occurs at a rapid rate at room temperature. It is best to refrigerate eggs at 40°F.

9) What’s the difference between real eggs and egg substitutes?

Shell eggs include both the egg yolk and the egg white while in most cases egg substitutes, available to consumers, are only egg whites which have been pasteurized (quickly heated). Egg substitutes may exhibit different characteristics from shell eggs during cooking.

10) Should I wash the eggs before or after refrigeration?

Commercially produced eggs are washed before packing and do not need additional washing before preparation.

11) How can I safely prepare recipes that call for raw eggs?

The USDA recommends the following alterations to standard raw egg recipes:

Egg mixtures are safe if they reach 160 °F, so homemade ice cream and eggnog can be made safely from a cooked egg-milk mixture. Heat it gently and use a food thermometer.

Dry meringue shells are safe. So are divinity candy and 7-minute frosting, made by combining hot sugar syrup with beaten egg whites. Avoid icing recipes using uncooked eggs or egg whites.

Meringue-topped pies should be safe if baked at 350 °F for about 15 minutes. Chiffon pies and fruit whips made with raw, beaten egg whites cannot be guaranteed to be safe. Instead, substitute pasteurized dried egg whites, whipped cream, or a whipped topping.

To make a recipe safe that specifies using eggs that aren’t cooked, heat the eggs in a liquid from the recipe over low heat, stirring constantly, until the mixture reaches 160 °F. Then combine it with the other ingredients and complete the recipe.

To determine doneness in egg dishes such as quiche and casseroles, the center of the mixture should reach 160 °F when measured with a food thermometer.

4. Nutritional Benefit of eggs:

1) Are eggs high in saturated fat?

NO, in fact a large egg only provides 1.5 grams of saturated fat while they provide 2.6 grams of healthy mono and poly unsaturated fats.

2) Are eggs fattening?

NO, a large egg only supplies 75 calories which is very little considering the nutrition and satisfaction from hunger that an egg provides.

2) Are there any trans fats in eggs?

Eggs contain less than 0.5grams of trans fats which is the acceptable limit for foods to claim no trans fat content.

4) I’m worried about my cholesterol, should I just eat the egg whites?

The egg yolk provides the majority of the vitamins and minerals found in an egg including about 40% of the protein. While everyone is different and has different medical histories, scientific research has not shown an association between egg consumption and heart disease. Since a small percentage of the population appears to be sensitive to dietary cholesterol intake which causes increases in their LDL blood cholesterol levels, it is advisable to have your blood cholesterol (LDL) levels checked regularly if you are concerned. Cutting back on saturated and trans fat intake is the most effective way to reduce your blood cholesterol levels.

5) Will eating eggs increase my risk of getting heart disease?

There have been many years of research devoted to this topic and no well controlled scientific study has proven a relationship between egg consumption and heart disease. In fact, a study at Harvard Medical School that considered the health of 117,000 men and women found that the consumption of 1 egg a day is unlikely to have an impact on the risk of heart disease or stroke. (Hu et al, JAMA 1999, 281(15):1387). However, there are some members of the population that have been found to be sensitive to dietary cholesterol intake in which case they should monitor their blood cholesterol levels (LDL: HDL) before and after a period of a few weeks of egg consumption to determine what effect egg consumption has on them.

6) How many eggs can I eat in a day? In a week?

Depending on your personal medical history there is no specific restriction on egg intake. Like any food, moderation should be your guide.

7) Can eggs help me to lose weight?

Eggs provide a considerable amount of high quality protein for the number of calories that they offer. Protein consumption has been found to make one feel more satisfied which leads to greater weight loss. A recent study done at Wayne State University showed that obese subjects who ate a breakfast of 2 eggs and toast where less hungry later in the day and considered themselves more satisfied than subjects who consumed an equal calorie breakfast consisting of a bagel and yogurt. (Vander Wal et al, J Am Coll Nutr, 2005, 24(6): 510) 

8) Can eggs help my eyesight?

Yes, egg yolks contain lutein and zeaxanthin, two substances that are stored in the eye which are thought to protect the eye from damage due to aging associated with ultraviolet light exposure. Recent research has shown that eggs have a very well absorbed form of lutein and zeazanthin, substances which can protect the eye from the risk of cataracts and age related macular degeneration.

9) Are “designer” eggs worth the price?

Depending on your total dietary intake, eggs enhanced with extra nutrients such as omega-3 fatty acids can correct some nutrient deficiencies in your diet. Other specialty eggs offer the consumer a choice dependent on their beliefs and dietary practices.

10) What is a fertile egg?

Generic shell eggs are not fertile. They are only the reproductive product of the laying hen that has not had contact with a male rooster. Eggs that are sold as fertile eggs signify that a rooster was present when the eggs were laid and can be incubated and possibly developed into chicks. Fertile eggs are not more nutritious than non fertile eggs, do not keep as well as nonfertile eggs and are more expensive to produce. Fertile eggs may contain a small amount of male hormone, but there are no known advantages.

11) What nutrients do I get from eating eggs?

The egg is a powerhouse of nutrition for its size and caloric content. According to USDA National Nutrient Database for Standard Reference #18, A large egg contains the following nutritional profile: 






74 kcal


55 kcal


6.29 g

3.6 g

2.70 g

Total fat

4.97 g

0.06 g

4.51 g


0.39 g

0.24 g

0.61 g


0 g

0.0 g

0.0 g


27 mg

2 mg

22 mg


0.92 mg

0.03 mg

0.46 mg


6 mg

4 mg

1 mg


96 mg

5 mg

66 mg


67 mg

54 mg

19 mg



55 mg

8 mg



0.01 mg

0.39 mg



0.008 mg

0.013 mg



0.004 mg

0.009 mg


15.0 mcg

6.6 mcg

9.5 mcg


0.035 mg

0.001 mg

0.030 mg


0.239 mg

0.145 mg

0.090 mg


0.035 mg

0.035 mg

0.004 mg

Pantothenic Acid

0.179 mg

0.063 mg

0.508 mg

Vitamin B6

0.071 mg

0.002 mg

0.059 mg


24 mcg

1 mcg

25 mcg

Vitamin B12

0.65 mcg

0.03 mcg

0.33 mcg

Vitamin A

244 IU

0 IU

245 IU

Vitamin E

0.48 mg

0.00 mg

0.44 mg

Vitamin D

18 IU

0 IU

18 IU

Vitamin K

0.1 mcg

0.0 mcg

0.1 mcg


212 mg

0 mg

210 mg


166 mcg

0 mcg

186 mcg

12) Where do eggs fit into the new USDA MYPYRAMID eating plan?

Eggs are a member of the meat, poultry, fish, eggs, beans and legumes food group (purple band). One egg is considered equivalent to one serving or one ounce.

Back to Top


Scroll to Top