1. For: ADVS 1110 Introduction to Animal Science
Eggcellent Eggs!!
For:
ADVS 1110
Introduction to Animal Science

2. Types of Eggs

3. Overview
Egg Industry
Parts of the egg
Grades of eggs
Sizes of eggs

4. Egg Industry In 2015 the United States produced 83 billion table eggs.
2015 per capita consumption was eggs.
High point in per capita egg consumption was 402 eggs in 1945.
Per capita consumption reached it lowest in eggs.

5. Egg Industry Current Top Egg Producing States: Iowa- 45,459,000 layers
Ohio- 32,604,000 layers
Indiana- 28,437,000 layers
Pennsylvania- 25,841,000 layers
Texas- 19,302,000 layers
Utah ranks 31st.

6. The Parts of the Egg

7. The Parts of an Egg Albumen Shell Yolk Air Cell Outer Shell Membrane
Chalaza
Inner shell membrane
Germinal Disc
Vitelline Membrane

8. The Primary Components of the Egg:
Shell
Membranes
Albumen
Yolk

9. Shell Egg’s outer covering 9-12% of total weight
The shell is the egg’s first defense against bacterial contamination
Made of mostly calcium carbonate
Shell strength is determined by a hens diet (particularly calcium) and thickness by a hens age.

10. Shell
Each egg has up to 17, pores on the shell surface. A greater number are on the larger end.
Pores allow moisture and CO2 to move out and air to move in to form the air cell.
A protective covering called the cuticle or the bloom covers the shell to block the pores to keep egg fresh and prevent contamination.

11. Shell

12. Shell Membrane Inner and outer shell membrane.
Protect against bacterial penetration
Air cell forms between the two membranes.
Inner shell membrane

13. Albumen Also known as “egg white.”
Contains more than half the eggs total protein, potassium and sodium.
More opalescent than white.
Cloudy appearance comes from CO2 which escapes as the egg ages, so older eggs are clearer than fresh eggs.
Tends to thin out with age.
Albumen

14. Air Cell Empty space between the albumen and the shell.
At the large end of the egg.
When egg is first laid it is warm, as it cools, the content contracts and the inner shell membrane separates from the outer shell membrane forming the air cell.
Air cell becomes larger with age
Size of air cell is used in determining grade of egg.

15. Germinal Disc The entrance leading into the yolk.
Slight depression on the yolk
If the egg were to be fertilized-the sperm would enter through the germinal disc.
Where the females genetic material is found.
Germinal disc

16. Chalaza
Chalaza
Ropey strands of egg white which anchor the yolk in place in the center of the egg white.
The more prominent the chalaza, the fresher the egg.
Does not need to be removed.
Chalaza

17. Vitelline Membrane Also known as the yolk membrane.
Clear seal which holds egg yolk.
Protects the yolk from breaking.
Is weakest at the germinal disc and weakens with age.
Vitelline Membrane

18. Yolk Yellow portion of egg. 33% of the liquid weight of the egg.
Contains all of the fat in the egg and a little less than half of the protein.
Contains more vitamins than the egg white.
The yolk is the main source of nutrients for the embryo.

19. The Parts of an Egg Albumen Shell Yolk Air Cell Outer Shell Membrane
Chalaza
Inner shell membrane
Germinal Disc
Vitelline Membrane

20. Grading of Eggs
Grade is determined by interior and exterior egg quality.
Grade is designated by letters : AA, A, B.
AA is the best grade.
There is no nutritional difference between the grades.
Most B grades are used by institutional egg users and never make their way to the grocery store.

21. Exterior
The shell is checked for cleanliness, strength, texture and shape. Higher grades must be clean.
Cracks or unsound shells are restricted eggs.
Shell should be oval with one end larger than the other.
Thin spots or rough areas may be permitted under B grade of egg.

22. Summary: Exterior Quality Factors
Cleanliness of shell
Soundness of shell (e.g., cracks, checks, and texture, etc.)
Shape

23. Interior
“Candling” method or the breakout method is used. (visual appraisal with light through egg)
Albumen judged based on clarity and firmness.
Should be clear of discolorations or foreign bodies.
Twirling an egg before a candling light will show the thickness of the albumen by observing how fast the yolk moves.
The yolk is graded on distinctness of outline and absence of defects such as a blood spot.
Higher grade eggs have a shallow air cell.
AA <1/8 inch air cell
A >3/16 inch air cell
B No limit on size of air cell

24. Interior
Candling eggs by hand.

25. Interior
Candling a good egg.

26. Summary: Interior Quality Factors
Albumen thickness
Condition of yolk
Size and condition of air cell
Abnormalities (e.g., blood spots, meat spots, etc.)

27. Sizing of Eggs Egg size is determined by weight.
Each carton contains eggs of similar weights.
Grade quality and weight are not related.
6 sizes of eggs:
Size
Pee Wee
Small
Medium
Large
Extra Large
Jumbo

28. Consumer Weight Classes of Eggs: Net Weight Per Dozen
Size
Ounces (per dozen)
Jumbo 30
Extra Large 27
Large 24
Medium 21
Small 18
Peewee 15

29. Question: Which came first the chicken or the egg?

30. The End

31. Questions?