Eggcellent Eggs!!Eggcellent Eggs!!By Christina StoryBy Christina Story

OverviewOverview

Egg Industry Parts of the egg Review of parts Grades of eggs Sizes of eggs Review

Egg IndustryEgg Industry In 2003 the United States produced

73.93 billion table eggs. 2003 per capita consumption was

254.1 eggs. High point in per capita egg

consumption was 402 eggs in 1945. Top egg producing state is Iowa

with 44,271 layer hens. California is ranked # 5 with 20,073

layer hens.

Let’s Learn Let’s Learn The Parts of the EggThe Parts of the Egg

ShellShell

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.

Shell

Each egg has up to 17,000 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.

ShellShell

Shell MembraneShell Membrane

Inner and outer shell membrane.

Protect against bacterial penetration Air cell forms between the two

membranes.

Inner shell membrane

Outer shell membrane

AlbumenAlbumen

Also known as “egg white.” Contains more than half the eggs total

protein, potassium and sodium. More opalescent that 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

Albumen

Air CellAir 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.

Air Cell

Germinal DiscGerminal Disc

The entrance leading into the center of 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

ChalazaChalaza

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

Chalaza

Vitelline MembraneVitelline Membrane

Also known as the yolkmembrane.

Clear seal which holds egg yolk. Protects the yolk from breaking. Is weakest at the germinal disc and

weakens with age.

Vitelline Membrane

YolkYolk

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 a source of food for the embryo.

Yolk

Let’s Review!!Let’s Review!!

Review of the Parts of an Review of the Parts of an EggEgg

Yolk

Vitelline Membrane

Chalaza

Germinal Disc

Air Cell

Albumen

Shell

Inner shell membrane

Outer Shell Membrane

Grading of EggsGrading 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.

ExteriorExterior

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.

InteriorInterior

Candling method or the breakout method is used. 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

Sizing of EggsSizing 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:

Pee Wee

Small Medium

Large Extra Large

Jumbo

Less than 42 g

At least 42 g

At least49g

At least 56 g

At least 63 g

70 g or more

Weight

Size

Let’s Review!Let’s Review!

Review QuestionsReview Questions

Q: What determines the grade of an egg? A: Interior and exterior quality

Q: What are the grades of eggs? A: AA, A, B

Q: What determines the “size” of an egg? A: weight in grams

Q: What are the methods for determining the interior quality for grading?

A: the candling or breakout method. Q: What is the top egg producing state in the United States?

A: Iowa Q: What is the per capita consumption of eggs in the US?

A. 254.1 eggs per person

The ENDThe END

Resources:Resources:

www.ext.vt.edu/resources/4h/virtualfwww.ext.vt.edu/resources/4h/virtualfarm/poultry/poultry_eggparts.htmlarm/poultry/poultry_eggparts.html

http://www.eggs.ca/eggfacts/egggrade.asphttp://www.eggs.ca/eggfacts/egggrade.asp http://www.georgiaeggs.org/http://www.georgiaeggs.org/ www.unitedegg.orgwww.unitedegg.org www.aeb.org/learnmore/eggfacts.htwww.aeb.org/learnmore/eggfacts.ht

mm

Thank You!Thank You!