Storey's Guide to Raising Chickens (59 page)

Certain species of bacteria (such as
Streptococcus
and
Staphylococcus
) tolerate dry conditions and are therefore able to survive on an egg’s shell. These bacteria dwindle during storage but are replaced by other species (including
Pseudomonas
) that cause eggs to rot. The presence of
Pseudomonas
may be detected by a pink, iridescent, or deep green color in an egg’s white and perhaps by a sour smell emitted when the egg is broken open. A variety of molds (
Penicillium
,
Alternaria
,
Rhizopus
) that get on the shells of eggs washed in dirty water or stored in humid conditions may also penetrate the shell and cause spoilage.

Salmonella
bacteria may be either on the shell or inside the egg when it is laid. These bacteria can cause serious illness in humans but only if allowed to multiply, which happens when a contaminated egg is held for too long at room
temperature. The problem gets worse if the egg is combined with other eggs in a mixture left on the counter and then undercooked or served as is.

Although you are unlikely to get
Salmonella
poisoning from your own carefully homegrown eggs, cooking them puts you on the safe side by destroying any
Salmonella
that might be present. A thoroughly cooked egg has its white cooked through and its yolk at least beginning to thicken — the yolk need not be hard, but it should not be runny. Cook eggs slowly to make sure they’re heated all the way through.

Keep hot foods containing eggs at 140°F (60°C) or warmer and cold foods at 40°F (4°C) or cooler. Including acid ingredients, such as lemon juice or vinegar, in foods and recipes containing raw eggs retards bacterial growth. Even so, eat such foods immediately or keep them refrigerated.

To avoid food poisoning follow these tips:

Collect eggs often, and refrigerate them promptly.

Discard seriously dirty or cracked and leaking eggs.

Wash hands and utensils after handling raw eggs.

Immediately cook or refrigerate foods prepared with raw or undercooked eggs, and cook them within 24 hours.

Cook eggs and egg-rich foods to 160°F (71°C) and serve them immediately, or cool quickly and refrigerate.

Promptly refrigerate leftovers, and use them within 4 days.

Eggs have often been called the perfect food. One egg contains almost all the nutrients necessary for life, lacking only vitamin C. It also contains the antioxidants
lutein
and
zeaxanthin
, which help prevent the eye disease
macular degeneration
, and
choline
, which aids the functioning of your brain and helps reduce your risk of heart disease.

A large egg is approximately 31 percent yolk, 58 percent white, and 11 percent shell. Aside from the shell, an egg has about 75 percent water, and the remainder is about 12 percent protein and 12 percent fat.

The yolk is basically an oil-water emulsion containing proteins, fats, pigment, and a number of minor nutrients. Yolks contain
lecithin
, which acts as an emulsifier for making mayonnaise and hollandaise sauce. Some evidence shows that lecithin may affect the human brain function by improving memory, as well as help reduce cholesterol. Unfortunately, most of an egg’s cholesterol and calories are also in the yolk. The exact caloric value of an egg depends on its size.

The white is made up of water combined with several different kinds of protein. Egg protein is complete, since it contains all the essential amino acids. It is
among the highest-quality protein found in food, second only to mother’s milk. One large egg contains approximately 6.25 grams of protein, roughly equivalent to 1 ounce (28 g) of lean meat, poultry, fish, or legumes.

One of the proteins in raw eggs,
avidin
, ties up the vitamin
biotin
as part of an egg’s defenses against bacteria, since most bacteria can’t grow without biotin. Pets are sensitive to the effects of avidin and should not routinely be fed raw eggs. A human would have to eat two dozen raw eggs a day to be affected. Cooking an egg inactivates the avidin.

Many people have the mistaken belief that fertile eggs are more nutritious than infertile eggs. The idea is encouraged by unscrupulous sellers who cater to health-conscious consumers and find they can charge more by claiming that their fertile eggs are more nutritious than the infertile eggs commonly sold in supermarkets. In truth, a sperm contributes an insignificant amount of nutrients to a fertilized egg.

Another idea promoted in health-food circles is that eggs with colored shells are more nutritious than white-shell eggs. Although eggs from backyard or pastured hens are likely to have brown or blue-green shells, in contrast to the white shells of commercial eggs, the shell color itself has nothing to do with an egg’s nutritional value.

The nutritional difference is not in the shell color but in how the eggs are produced. White-shell eggs produced by hens on pasture will be more nutritious than eggs with colored shells laid by caged hens. The eggs laid by hens with access to pasture or other green feeds, no matter what color the shell, contain less cholesterol and saturated fat, more vitamins A, D & E, and more beta carotene, folic acid, and omega-3 polyunsaturated fatty acids than factory-farm-produced eggs laid by caged hens. Eggs from hens fed flax seed also have more omega-3s.

CALORIE CONTENT OF EGGS

Cholesterol is a fatty substance found in the bodies of chickens and humans alike. It is required for both the synthesis of vitamin D from sunshine and the production of sex hormones. But it can also collect in the bloodstream and clog the arteries. Thanks to media scare tactics, many people have the impression that all the cholesterol you eat goes straight into your bloodstream. Not true.

Most of the cholesterol in your body is manufactured within your body. The amount of manufactured cholesterol is regulated by your liver, based on your dietary intake. Some people have better controlling mechanisms than others.

Cholesterol in the foods you eat does somewhat increase your blood cholesterol, but a healthy body compensates by producing less or excreting more cholesterol to maintain the proper blood level. Medical practitioners who don’t buy into the cholesterol panic point out that even if all the cholesterol in an egg went into your bloodstream — which isn’t likely — you’d have to eat five jumbo eggs a day to raise your cholesterol level from 150 to 152.

Saturated fat in your diet is the greater culprit in increasing your blood cholesterol. Many foods that contain cholesterol are high in saturated fat. An egg is the rare exception — it is high in cholesterol but contains little saturated fat. The yolk of one large egg contains about 210 milligrams of cholesterol and 1.5 grams of saturated fat — compared to no more than 22 grams of saturated fat recommended for a person eating two thousand calories per day.

A study reported in
Medical Science Monitor
showed that eating one or more eggs a day does not increase the risk of heart disease or stroke among healthy adults but may decrease blood pressure. And a review of 30 years of cholesterol research published in the
Journal of the American College of Nutrition
concluded that eating eggs has little relationship to high blood cholesterol or the incidence of heart disease.