Eggs
   
 
 
Inspection of Eggs by density

The Inspection of eggs by this method is carried out by water, wherein eggs samples to be inspected are put in a container filled with water and the results are interpreted as  following:-

  • If the egg rests lying on its side touching the bottom of the container, its age is less than 24 hours.

  • if the egg rests at the bottom of the container, forming an angle of 30o with its surface, its age would be around 4 days.

  • If the egg rests at the bottom of the container, rising from one of its sides and forming 45o angle with its surface, its age would be around one week.

  • If the egg floats and a big part thereof appears above the water surface, then it is old and not safe for consumption.

Inspection by light

The basis working of this method depends on the transparency of the eggs and light penetration therein, and the inspection is carried by putting the eggs in an apparatus  (comprising a box closed from all sides, with  one side having a hole of the size of an egg and fitted with an electric bulb) between a source of light and the eye, where the existence of yolk rounded in a transparent medium can be observed.

An unsafe egg would appear in one or more of the following conditions.

  • Egg white and yolk are mixed

  • Yolk adheres to the shell of the egg

  • Yolk is mottled
  • Egg white seems dark and mixed with other colours
  • If the air-vacuum appears big and foreign bodies appear inside the egg
 
 

To avoid the possibility of foodborne illness, fresh eggs must be handled carefully. Even eggs with clean, uncracked shells may occasionally contain bacteria called Salmonella that can cause an intestinal infection. The most effective way to prevent egg-related illness is by knowing how to buy, store, handle and cook eggs—or foods that contain them—safely. That is why the U.S. Food and Drug Administration (FDA) requires all cartons of shell eggs that have not been treated to destroy Salmonella must carry the following safe handling statement:

 
 

Buy Right

  • The eggs and make sure that the eggs are clean and the shells are not cracked.

  • Refrigerate promptly. Store eggs in their original carton and use them within 3 weeks for best quality.

Keep Everything Clean

  • Before preparing any food, remember that cleanliness is key! Wash hands, utensils, equipment, and work surfaces with hot, soapy water before and after they come in contact with eggs and egg-containing foods

 
   

Cook Thoroughly

Thorough cooking is perhaps the most important step in making sure eggs are safe.

  • Do not consume raw or undercooked eggs.

  • Cook eggs until both the yolk and the white are firm. Scrambled eggs should not be runny.

  • Casseroles and other dishes containing eggs should be cooked thoroughly to 75 °C Use a food thermometer to be sure.

  • Avoid recipes that call for eggs that are raw or undercooked when the dish is served -e.g. Milk shakes, homemade mayonnaise and ice cream.

 
   

Serve Safely

Bacteria can multiply in temperatures from 5° C to 60 °C, so it's very important to serve foods safely.

  • Serve cooked eggs and egg-containing foods immediately after cooking.

  • For buffet-style serving, hot egg dishes should be kept hot, and cold egg dishes kept cold.

  • Eggs and egg dishes, such as quiches or soufflés, may be refrigerated for serving later but should be thoroughly reheated to 75° C before serving.

 
 
 

Chill Properly

  • Cooked eggs, including hard-boiled eggs, and egg-containing foods should not sit out for more than 2 hours. Within 2 hours either reheat or refrigerate.

  • Refrigerate leftover cooked egg dishes and use within 24 hrs.. When refrigerating a large amount of a hot egg-containing leftover, divide it into several shallow containers so it will cool quickly.

 
   
 

Taking eggs to work or school or picnic

If taking eggs to work school or picnic then take full boiled eggs preferbly.
   
   
 
   
 

BLOOD SPOTS

Also called meat spots. Occasionally found on an egg yolk. Contrary to popular opinion, these tiny spots do not indicate a fertilized egg. Rather, they are caused by the rupture of a blood vessel on the yolk surface during formation of the egg or by a similar accident in the wall of the oviduct. Less than 1% of all eggs produced have blood spots.

COLOR

Egg shell and yolk color may vary, but color has nothing to do with egg quality, flavor, nutritive value, cooking characteristics or shell thickness

Shell:

The color comes from pigments in the outer layer of the shell and may range in various breeds from white to deep brown. The breed of hen determines the color of the shell. Breeds with white feathers and ear lobes lay white eggs; breeds with red feathers and ear lobes lay brown eggs. White eggs are most in demand among American buyers. In some parts of the country, however, particularly in New England, brown shells are preferred. The Rhode Island Red, New Hampshire and Plymouth Rock are breeds that lay brown eggs. Since brown-egg layers are slightly larger birds and require more food, brown eggs are usually more expensive than white.

White:

Egg albumen in raw eggs is opalescent and does not appear white until it is beaten or cooked. A yellow or greenish cast in raw white may indicate the presence of riboflavin. Cloudiness of the raw white is due to the presence of carbon dioxide which has not had time to escape through the shell and thus indicates a very fresh egg.

Yolk:

Yolk color depends on the diet of the hen. If she gets plenty of yellow-orange plant pigments known as xanthophylls, they will be deposited in the yolk. Hens fed mashes containing yellow corn lay eggs with medium yellow yolks, while those eating wheat or barley yield lighter-colored yolks.

Sometimes there is a greenish ring around hard-cooked egg yolks. It is the result of sulfur and iron compounds in the egg reacting at the surface of the yolk. It may occur when eggs are overcooked or when there is a high amount of iron in the cooking water. Although the color may be a bit unappealing, the eggs are still wholesome and nutritious and their flavor is unaffected. Greenish yolks can best be avoided by using the proper cooking time and temperature and by rapidly cooling the cooked eggs.

Occasionally several concentric green rings may be seen in hard-cooked egg yolks. A yolk develops within the hen in rings. Iron in the hen's feed or water as the rings are formed may cause this coloring.

 
 

AIR CELL

The empty space between the white and shell at the large end of the egg.

As the egg ages, moisture and carbon dioxide leave through the pores of the shell, air enters to replace them and the air cell becomes larger.

ALBUMEN

Also known as egg white. Albumen accounts for most of an egg's liquid weight, about 67%. It contains more than half the egg's total protein, niacin, riboflavin, chlorine, magnesium, potassium, sodium and sulphur. The albumen consists of 4 alternating layers of thick and thin consistencies. From the yolk outward, they are designated as the inner thick or chalaziferous white, the inner thin white, the outer thick white and the outer thin white. Egg white tends to thin out as an egg ages because its protein changes in character. That's why fresh eggs sit up tall and firm in the pan while older ones tend to spread out.

Albumen is more opalescent than truly white. The cloudy appearance comes from carbon dioxide. As the egg ages, carbon dioxide escapes, so the albumen of older eggs is more transparent than that of fresher eggs.

When egg albumen is beaten vigorously, it foams and increases in volume 6 to 8 times. Egg foams are essential for making souffles, puffy omelets and sponge cakes.

CHALAZA

Ropey strands of egg white which anchor the yolk in place in the center of the thick white. They are neither imperfections nor beginning embryos.

The more prominent the chalazae, the fresher the egg. Chalazae do not interfere with the cooking or beating of the white and need not be removed, although some cooks like to strain them from stirred custard.

GERMINAL DISC

The entrance of the latebra, the channel leading to the center of the yolk. The germinal disc is barely noticeable as a slight depression on the surface of the yolk. When the egg is fertilized, sperm enter by way of the germinal disc, travel to the center and a chick embryo starts to form.

MEMBRANES:
 

  • Shell Membranes
    Just inside the shell are two shell membranes, inner and outer. After the egg is laid and it begins to cool, an air cell forms between these two layers at the large end of the egg.

  • Vitelline Membrane:
    This is the covering of the yolk. Its strength protects the yolk from breaking. The vitelline membrane is weakest at the germinal disc and tends to become more fragile as the egg ages.

SHELL

The egg's outer covering, accounting for about 9 to l2% of its total weight depending on egg size. The shell is the egg's first line of defense against bacterial contamination.

The shell is largely composed of calcium carbonate (about 94%) with small amounts of magnesium carbonate, calcium phosphate and other organic matter including protein.

Seven to 17 thousand tiny pores are distributed over the shell surface, a greater number at the large end. As the egg ages, these tiny holes permit moisture and carbon dioxide to move out and air to move in to form the air cell. The shell is covered with a protective coating called the cuticle or bloom. By blocking the pores, the cuticle helps to preserve freshness and prevent microbial contamination of the contents.

YOLK

The yolk or yellow portion makes up about 33% of the liquid weight of the egg. It contains all of the fat in the egg and a little less than half of the protein.

With the exception of riboflavin and niacin, the yolk contains a higher proportion of the egg's vitamins than the white. All of the egg's vitamins A, D and E are in the yolk. Egg yolks are one of the few foods naturally containing vitamin D.

The yolk also contains more phosphorus, manganese, iron, iodine, copper, and calcium than the white, and it contains all of the zinc.

Double-yolked eggs are often produced by young hens whose egg production cycles are not yet completely synchronized. They're often produced, too, by hens who are old enough to produce Extra Large eggs.

In fertilized eggs, the yolk is the site of embryo formation

It is the yolk which is responsible for the egg's emulsifying properties.

FERTILE EGGS

Eggs which can be incubated and developed into chicks. Fertile eggs are not more nutritious than nonfertile 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.

FRESHNESS

How recently an egg was laid has a bearing on its freshness but is only one of many factors. The temperature at which it is held, the humidity and the handling all play their part. These variables are so important that an egg one week old, held under ideal conditions, can be fresher than an egg left at room temperature for one day. The ideal conditions are temperatures that don't go above 4°C and a relative humidity of 70 to 80%.

Proper handling means prompt gathering, washing and oiling of the eggs within a few hours after laying. Most commercially produced eggs reach supermarkets within a few days of leaving the laying house. If the market and the buyer handle them properly, they will still be fresh when they reach the table.

As an egg ages, the white becomes thinner and the yolk becomes flatter. These changes do not have any great effect on the nutritional quality of the egg or its functional cooking properties in recipes. Appearance may be affected, though. When poached or fried, the fresher the egg, the more it will hold its shape rather than spread out in the pan. On the other hand, if you hard cook eggs that are at least a week old, you'll find them easier to peel after cooking and cooling than fresher eggs.