How Does Salmonella Infect Eggs?
Bacteria can be on the outside of a shell egg. That’s because the egg exits the hen’s body through the same passageway as feces is excreted. That’s why eggs are washed and sanitized at the processing plant. Bacteria can be inside an un cracked, whole egg. Contamination of eggs may be due to bacteria within the hen’s ovary or oviduct before the shell forms around the yolk and white. SE doesn’t make the hen sick. It is also possible for eggs to become infected by Salmonella Enteritidis fecal contamination through the pores of the shells after they’re laid.

What Part Carries Bacteria?
Researchers say that, if present, the SE is usually in the yolk or "yellow." However, they can’t rule out the bacteria being in egg whites. So everyone is advised against eating raw or undercooked egg yolks and whites or products containing raw or undercooked eggs.

Should eggs be eaten Raw?
No one should eat foods containing raw eggs. This includes "health food" milk shakes made with raw eggs, Caesar salad, Hollandaise sauce, and any other foods like homemade mayonnaise, ice cream which the egg ingredients are not cooked.

Why Should Eggs Be Refrigerated?
Temperature fluctuation is critical to safety. With the concern about Salmonella, eggs gathered from laying hens should be refrigerated as soon as possible. After eggs are refrigerated, they need to stay that way. 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.

Should You Wash Eggs before Storage?
No. When the egg is laid, a protective coating is put on the outside by the hen.

Why Do Hard-Cooked Eggs Spoil Faster than Fresh Eggs?
When shell eggs are hard cooked, the protective coating is washed away, leaving bare the pores in the shell for bacteria to enter and contaminate it. Hard-cooked eggs should be refrigerated within 2 hours of cooking and used within a week.

Safe Storage
Make sure eggs refrigerated after purchase in the store. Any bacteria present in an egg can multiply quickly at room temperature.

Bringing Eggs Home from the Store
Take eggs straight home and store them immediately in the refrigerator set at 5 °C or below. Keep them in their carton and place them in the coldest part of the refrigerator, not in the door. Don’t wash eggs. That could remove the protective coating on the shell and increase the potential for bacteria on the shell to enter the egg.

Is It Safe to Use Eggs That Have Cracks?
Bacteria can enter eggs through cracks in the shell. Never purchase cracked eggs. However, if eggs crack on the way home from the store, break them into a clean container, cover it tightly, keep refrigerated, and use within 2 days. If eggs crack during hard cooking, they are safe.

How Are Eggs Handled Safely?
Proper refrigeration, cooking, and handling should prevent most egg-safety problems. Persons can enjoy eggs and dishes containing eggs if these safe handling guidelines are followed.

Wash hands, utensils, equipment, and work areas with hot, soapy water before and after contact with eggs.

Don’t keep eggs out of the refrigerator more than 2 hours.

Raw eggs and other ingredients, combined according to recipe directions, should be cooked immediately or refrigerated and cooked within 24 hours.

Serve cooked eggs and dishes containing eggs immediately after cooking, or place in shallow containers for quick cooling and refrigerate at once for later use. Use within 1 to 2 days.

What is the Cholesterol Content of Eggs?
The most recent studies show that cholesterol content of one large egg to be 213 milligrams. All of the cholesterol is in the yolk.
An egg is a good source of complete protein, vitamins A and B-12, riboflavin, folacin, iron, zinc, and phosphorus.

Does the Color of the Shell Affect the Egg’s Nutrients?
No. The breed of the hen determines the color of her eggs.

Is the Appearance of Eggs Related to Food Safety?
Sometimes, but not usually. Variation in egg color is due to many factors.

Blood spots are caused by a rupture of one or more small blood vessels in the yolk at the time of ovulation. It does not indicate the egg is unsafe.

A cloudy white (albumen) is a sign the egg is very fresh. A clear egg white is an indication the egg is aging.

The color of yolk varies in shades of yellow depending upon the diet of the hen. If she eats plenty of yellow-orange plant pigments, such as from marigold petals and yellow corn, the yolk will be a darker yellow than if she eats a colorless diet such as white cornmeal. Artificial color additives are not permitted in eggs.

A green ring on a hard-cooked yolk is a result of overcooking, and is caused by sulphur and iron compounds in the egg reacting on the yolk’s surface. The green color can also be caused by a high amount of iron in the cooking water. Scrambled eggs cooked at too high a temperature or held on a steam table too long can also develop a greenish cast. The green color is safe to consume.

How Do Time and Refrigeration Affect Egg Quality?
The egg, as laid at 105 °F, normally has no air cell. It forms as the egg cools, usually in the large end of the egg, and develops between the two shell membranes. The air cell is formed as a result of the different rates of contraction between the shell and its contents.
Over time, the white and yolk of an egg lose quality. The yolk absorbs water from the white. Moisture and carbon dioxide in the white evaporate through the pores, allowing more air to penetrate the shell, and the air cell becomes larger. If broken open, the egg’s contents would cover a wider area. The white would be thinner, losing some of its thickening and leavening powers. The yolk would be flatter, larger and more easily broken. The chalazae (kah-LAY-zuh), the twisted cord-like strands of egg white that anchor the yolk in the center of the white, would be less prominent and weaker, allowing the yolk to move off center. Refrigeration slows the loss of quality over time.

What Does It Mean When an Egg Floats in Water?
An egg can float in water when its air cell has enlarged sufficiently to keep it buoyant. This means the egg is old Crack the egg into a bowl and examine it for an off-odor or unusable appearance before deciding to use or discard it. A spoiled egg will have an unpleasant odor when you break open the shell, either when raw or cooked.

Safe Cooking Methods        
Many cooking methods can be used to cook eggs safely including poaching, hard cooking, scrambling, frying and baking. However, eggs must be cooked thoroughly until yolks are firm. Scrambled eggs should not be runny.

What factors affect the color of meat ?
Myoglobin, a protein, is responsible for the majority of the red color. Myoglobin doesn't circulate in the blood but is fixed in the tissue cells and is purplish in color. When it is mixed with oxygen, it becomes oxymyoglobin and produces a bright red color. The remaining color comes from the hemoglobin which occurs mainly in the circulating blood, but a small amount can be found in the tissues after slaughter.

Color is also influenced by the age of the animal, the species, sex, diet, and even the exercise it gets. The meat from older animals will be darker in color because the myoglobin level increases with age. Exercised muscles are always darker in color, which means the same animal can have variations of color in its muscles.

In addition, the color of meat can change as it is being stored at retail and in the home. When safely stored in the refrigerator or freezer, color changes are normal for fresh meat and poultry.

Does a change in color indicate spoilage?
Change in color alone does not mean the product is spoiled. Color changes are normal for fresh product. With spoilage there can be a change in color -- often a fading or darkening. In addition to the color change, the meat will have an off odor, be sticky or tacky to the touch, or it may be slimy. If meat has developed these characteristics, it should not be used.

If the color of meat changes while frozen, is it safe?
Color changes, while meats are frozen, occur just as they do in the refrigerator. Fading and darkening, for example, do not affect their safety. These changes are minimized by using freezer-type wrapping and by expelling as much air as possible from the package.

When displayed at the grocery store, why is some meat bright red and other meat very dark in color?
Optimum surface color of fresh meat (i.e., dark cherry-red for lamb; grayish-pink for pork) is highly unstable and short-lived. When meat is fresh and protected from contact with air (such as in vacuum packages), it has the purple-red color that comes from myoglobin, one of the two key pigments responsible for the color of meat. When exposed to air, myoglobin forms the pigment, oxymyoglobin, which gives meat a pleasingly cherry-red color. The use of a plastic wrap that allows oxygen to pass through it helps ensure that the cut meats will retain this bright red color. However, exposure to store lighting as well as the continued contact of myoglobin and oxymyoglobin with oxygen leads to the formation of metmyoglobin, a pigment that turns meat brownish-red. This color change alone does not mean the product is spoiled.

What causes iridescent colors on meats?
Meat contains iron, fat, and other compounds. When light hits a slice of meat, it splits into colors like a rainbow. There are various pigments in meat compounds that can give it an iridescent or greenish cast when exposed to heat and processing. Wrapping the meat in airtight packages and storing it away from light will help prevent this situation. Iridescence does not represent decreased quality or safety of the meat.

What causes grayish or green color on cured meats?
Exposure to light and oxygen causes oxidation to take place, which causes the breaking down of color pigments formed during the curing process. Chemicals in the cure and oxygen, as well as energy from ultraviolet and visible light, contribute to both the chemical breakdown and microbial spoilage of the product.

What is the usual color of raw poultry?
Raw poultry can vary from a bluish-white to faint yellow. All of these colors are normal and are a direct result of breed, exercise, age, and/or diet. Younger poultry has less fat under the skin, which can cause the bluish cast.

Does a change in color indicate spoilage?
Change in color alone does not mean the product is spoiled. Color changes are normal for fresh product. With spoilage there can be a change in color -- often a fading or darkening. In addition to the color change, the poultry will have an off odor, be sticky or tacky to the touch, or it may be slimy. If poultry has developed these characteristics, it should not be used.

If the color of poultry changes while frozen, is it safe?
Color changes, while poultry are frozen, occur just as they do in the refrigerator. Fading and darkening, for example, do not affect their safety. These changes are minimized by using freezer-type wrapping and by expelling as much air as possible from the package.

What color and temperature is safely cooked poultry?
Safely cooked poultry can vary in color from white to pink to tan. Check the temperature in several locations, being sure to include the wing joint. All the meat—including any that remains pink—is safe to eat as soon as all parts reach at least 75° C.

What causes dark bones in cooked poultry?
Darkening of bones and meat around the bones occurs primarily in young (6-8 weeks) broiler-fryer chickens. Since the bones have not calcified or hardened completely, pigment from the bone marrow seeps through the bones and into the surrounding area. Freezing can also contribute to this darkening. The poultry is safe to eat when all parts have reached at least 75 ° C.

Why is some cooked poultry pink?
Chemical changes occur during cooking. Oven gases in a heated gas or electric oven react chemically with hemoglobin in the meat tissues to give it a pink tinge. Often meat of younger birds shows the most pink because their thinner skins permit oven gases to reach the flesh. Older animals have a fat layer under their skin, giving the flesh added protection from the gases. Older poultry may be pink in spots where fat is absent from the skin.