1. K-State home
  2. »College of Agriculture
  3. »ASI
  4. »Research and Extension
  5. »Poultry
  6. »Frequently Asked Questions
  7. »Processing and Marketing

Animal Sciences and Industry

Processing and Marketing Eggs and Poultry Meat

1. What causes eggs to contain blood spots?
Blood spots (hemorrhaging) occur in eggs when a malfunction happens as the yolk breaks away from the ovary. Factories contributing to this problem are genetics, excessive fright (wild birds, rodents, etc. scaring the birds), lack of vitamin K, and access to rodent poisons containing anticoagulant drugs. These eggs are removed during processing but are not harmful.

2. It is true that eggs from the Araucana (Easter Egg) breed of chickens contain less cholesterol than the eggs of other breeds?
There is virtually no difference in egg cholesterol content among the various breeds. An article in a popular gardening magazine once incorrectly published a story that Araucana chickens produced low cholesterol egg and this rumor continues to circulate. This has since been proven wrong by many researchers, including KSU.

3. What are the major egg abnormalities and their causes?
a. Double-yolk eggs. This is the result of two ova (yolks) being ovulated at the same time.

b .Yolk-less (rooster) eggs. If any foreign material gets into the oviduct, it may stimulate the oviduct to secrete albumen in much the same manner as the yolk.

c. Dented or severely misformed eggshells. Caused by a defect of the oviduct, or two eggs touching each other in the oviduct. Usually it is the same hen(s) in a flock that consistently lay eggs with deformed shells.

d. Worm in an egg. Very, very infrequently, a roundworm will get into the oviduct and be incorporated into the egg.

e. Egg inside an egg. Sometimes an egg is laid that is very large and when broken open it contains albumen and another entire egg inside. Perhaps a completed egg moves back up the oviduct and is "re-packaged".

4. What are the small brown spots found in the white of eggs?
These are meat spots which are pieces of tissue from the hen’s reproductive tract. Meat spots do not harm the egg. Eggs with large meat spots are removed during the grading process.

5. How can eggs be cleaned?
Slightly soiled eggs can be cleaned with fine sandpaper or steel wool. Eggs for market or incubation can be washed if done properly. Follow these washing producers:

a. Use an appropriate detergent-sanitizer and follow the manufacturer’s recommendations.

b. Wash in water that is 105-110°F. Leave eggs in water no longer than 3 minutes.

c. Never wash eggs in water that is cooler than the internal temperature of the eggs. Wash as soon as possible after gathering.

d. Change wash water frequently. Dry eggs as quickly as possible.

e. Store eggs at 45°F when done.

6. What causes variability in egg yolk color?
The color in egg yolks and the skin of yellow skinned breeds of chickens comes from the pigment called xanthophylls which is found in green plants and yellow corn. If hens are fed a ration that has very little of these ingredients, their yolks will be a light yellow in color and vice versa. Variability of yolk color in a flock can be due to disease, and from hens fed free choice, which causes variability in the intake of pigmented ingredients between hens.

7. What can hens be fed so the eggs will contain yolks with exotic colors, i.e. red, green, etc.?
Fat soluble dyes, such as Sudan III (red), Sudan Black (green-black), Scarlet B fat (red), and Eliziran Green can be given to hens to cause brightly colored egg yolks. Twenty to forty grams per day administered orally via soluble gelatin capsules will result in the desired colored yolks in 6-8 days. These dyes are available from biological supply houses. But, please don’t sell or eat the eggs - it is illegal!

8. What is the nutrient composition of eggs?
Proportion by weight are: shell - 10%, white - 60%, and yolk - 30%

 Whole EggWhiteYolkShell

9. What is the per capita consumption of eggs in the U.S.?
Per capita consumption has been in the 240's for the last few years.

10. What causes eggs to develop off-odors and flavors?
Most common cause is storage of eggs near flowers, fruits, vegetables, or petroleum products. Eggs pick up off-odors and flavors easily.

11. How long can fresh eggs be stored in the refrigerator?
Good quality eggs can be stored for 3-4 weeks in a properly operating refrigerator. Quality will decline slower if the eggs are left in the carton instead of stored in the egg tray on the door.

12. Can eggs be preserved by freezing?
Whites - Break and separate the eggs, one at a time, being sure that no yolk gets in with the whites. Whites can be frozen without any added ingredients. Pour them into freezer containers, seal tightly, label with data and number of eggs. Whites can also be frozen in ice cube trays for easier measuring, then put in freezer containers. After whites are thawed, allow to set at room temperature for 30 minutes before using.

Yolks or Whole Eggs - The gelatin property of yolk causes it to thicken or gel when frozen. To help retard this gelation, you can add either 1/8 teaspoon salt, 1½ teaspoons sugar or 1½ teaspoons corn syrup per ¼ cup egg yolks (4 yolks) or whole eggs (2 whole eggs). Be sure and label the container with the quantity of eggs and the additive.

13. Is there a danger of feeding pets large amounts of raw eggs?
There is some danger because raw egg white contains avidin which complexes with the vitamin biotin, rendering it unavailable during digestion. Heating or cooking destroys avidin. However, your pet would have to eat an awful large amount of raw eggs before having a problem!

14. How can you determine which size of eggs is the best to buy?
Determine the price difference between the two sizes by the following formula and example:

X-Large eggs $1.05 vs. Large eggs 95 cents/doz.

1.05 minus 95 cents = 10 cents

95 divided by 8 = 12 (magic number)

The number 12 is higher than the price difference so the X-Large eggs are the better buy.

15. What are the stringy strands of material in the white of an egg?
These are the chalaza which center the yolk in place, in the center of the egg. They are more prominent in a fresh than an old egg.

16. Why are eggs oiled?
Sometimes a thin film of odorless, tasteless mineral oil is sprayed on eggs before they are cartoned. The oil replaces the natural bloom or protective coating on the outside of the egg, which is removed during washing. Oiling is not necessary for eggs that will be stored a short time (less than 30 days).

17. What are organic eggs?
They are eggs from hens fed feed ingredients that were grown without chemicals such as pesticides, fungicides, herbicides, or commercial fertilizer. From a nutritional standpoint, organic eggs and regular eggs are the same. Commercial laying rations do not contain added hormones, contrary to some claims.

18. What are the dressing yields for various types of poultry?


Ready-to-cook weight
To live weight (%)
Fowl (old hens and cocks)62-73

19. What causes bone darkening when broiler or fryers are cooked?
This is mainly a problem in a young chicken that has been frozen prior to cooking. Ice crystals formed during freezing rupture the blood cells allowing blood pigments to seep to the surface of the immature and not fully calcified bone. These pigments turn dark during cooking.

20. What causes the difference in color between white and dark poultry meat?
Red fibers, which contain large amount of myoglobin (an iron-containing oxygen carrying compound), predominate in dark meat. These fibers abound in muscles which are used continuously, such as the leg muscles. White fibers contain little myoglobin since they are used little, such as the flight (pectoral) muscles of the domesticated chicken.

21. How long can poultry meat be stored in frozen form?
Up to one year if the freezer is operating at -15°F.

22. Are fertile eggs more nutritious than nonfertile eggs?
No, chemical analyses have shown little difference in the nutritional content of fertile vs. nonfertile eggs.

23. What is "cold storage" eggs?
These are eggs held over 30 days at refrigeration temperatures. Almost no eggs sold at retail today are cold storage eggs.

24. At what temperature should eggs be held for storage?
Always store eggs before use at 45°F.