HOW ARE EGG FARMERS RESPONDING?
What is United Egg Producers (UEP) doing about this situation?
EGG STRUCTURE AND COMPOSITION
Doesn't the egg shell help protect an egg from bacteria?
Yes and no. The structure and composition of an egg provides many natural barriers to prevent passage of bacteria into the egg and discourage growth inside the egg. These natural protective barriers include the shell, the shell and yolk membranes, and layers of the white. The structure of the shell and shell membranes prevent bacteria from entering the egg. Both the shell membranes and white contain lysozyme, a substance that helps prevent contamination by physically damaging the bacteria. The layers of white also discourage bacterial growth because they are alkaline, bind nutrients bacteria need, and contain nutrients in a form that bacteria cannot use. The thick white discourages the movement of bacteria towards the yolk, which contains nutrients bacteria need. The last layer of white is composed of thick ropey strands, called chalazae, which holds the yolk centered in the egg where it receives the maximum protection from bacteria by all the other layers.
How often does a hen lay an egg?
The time from ovulation to laying is about 25 hours. Then about 30 minutes later, the hen will begin to form another egg.
How do bacteria, like Salmonella, infect eggs?
Bacteria can be both on the outside and inside of a shell egg. Eggs can become infected by fecal contamination when the egg exits the hen's body or by
dirt or dust in the environment; that's why eggs are washed and sanitized at the processing plant. Bacteria can also be inside an uncracked, whole egg. Contamination of eggs may be due to bacteria within the hen's ovary or oviduct being transferred into the contents before the shell forms around the yolk and white. The inside of an egg was once considered almost sterile. Over the years, however, scientists have found that Salmonella Enteritidis has the ability to grow both in the egg yolk and white.
What part inside the egg carries bacteria?
Researchers say that, if present, most bacteria is usually in the yolk. The yolk contains nutrients bacteria need to grow. Bacteria have also been found to grow in the white, however not as often as in the yolk. This is why the Egg Safety Center and FDA advise not to eat raw or undercooked egg yolks and whites or products containing raw or undercooked eggs.
What determines whether an egg is white or brown?
The breed of the chicken determines shell color of an egg—the white hens lay white eggs and the brown hens lay brown eggs. Brown chickens are usually larger and require more food to make an egg, which is why brown eggs cost more than white eggs.
Is the internal appearance of eggs related to egg safety?
The appearance of eggs may sometimes be related to food safety, but not usually. Variation in egg color is due to many factors. See the table below for some variations in egg appearance.