is an important public
health problem in the United States and several European countries.
, can be inside perfectly
normal-appearing eggs, and if the eggs are eaten raw or
undercooked, the bacterium can cause illness. During the 1980s,
illness related to contaminated eggs occurred most frequently in
the northeastern United States, but now illness caused by
is increasing in other parts of the country as
well. Consumers should be aware of the disease and learn how to
minimize the chances of becoming ill.
What are the symptoms?
A person infected with the
bacterium usually has fever, abdominal cramps, and diarrhea
beginning 12 to 72 hours after consuming a contaminated food or
beverage. The illness usually lasts four to seven days, and most
persons recover without antibiotic treatment. However, the diarrhea
can be severe, and the person may be ill enough to require
hospitalization. The elderly, infants, and those with impaired
immune systems may have a more severe illness. In these patients,
the infection may spread from the intestines to the blood stream,
and then to other body sites and can cause death unless the person
is treated promptly with antibiotics.
How eggs become contaminated
Unlike eggborne salmonellosis of past decades, the current
epidemic is due to intact and disinfected grade A eggs.
silently infects the ovaries of
healthy appearing hens and contaminates the eggs before the shells
are formed. Most types of
live in the intestinal
tracts of animals and birds and are transmitted to humans by
contaminated foods of animal origin.
Although most infected hens have been found in the northeastern
United States, the infection also occurs in hens in other areas of
the country. In the Northeast, approximately one in 10,000 eggs may
be internally contaminated. In other parts of the United States,
contaminated eggs appear less common. Only a small number of hens
seem to be infected at any given time, and an infected hen can lay
many normal eggs while only occasionally laying an egg contaminated
Who can be infected?
Healthy adults and children are at risk for egg-associated
salmonellosis, but the elderly, infants, and persons with impaired
immune systems are at increased risk for serious illness. In these
persons, a relatively small number of
can cause severe illness. Most of the deaths caused by
have occurred among the elderly in
nursing homes. Egg-containing dishes prepared for any of these
high-risk persons in hospitals, in nursing homes, in restaurants,
or at home should be thoroughly cooked and served promptly.
What is the risk?
In affected parts of the United States, we estimate that one in
50 average consumers could be exposed to a contaminated egg each
year. If that egg is thoroughly cooked, the
organisms will be destroyed and will not make the person sick. Many
dishes made in restaurants or commercial or institutional kitchens,
however, are made from pooled eggs. If 500 eggs are pooled, one
batch in 20 will be contaminated and everyone who eats eggs from
that batch is at risk. A healthy person's risk for infection by
is low, even in the northeastern
United States, if individually prepared eggs are properly cooked,
or foods are made from pasteurized eggs.
What can I do to reduce risk?
Eggs, like meat, poultry, milk, and other foods, are safe when
handled properly. Shell eggs are safest when stored in the
refrigerator, individually and thoroughly cooked, and promptly
consumed. The larger the number of Salmonella present in the egg,
the more likely it is to cause illness. Keeping eggs adequately
refrigerated prevents any Salmonella present in the eggs from
growing to higher numbers, so eggs should be held refrigerated
until they are needed.
Cooking reduces the number of bacteria present in an egg.
However, an egg with a runny yolk still poses a greater risk than a
completely cooked egg. Undercooked egg whites and yolks have been
associated with outbreaks of
infections. Both should be consumed promptly and not be held in the
temperature range of 40 to 140 for more than two hours. Reducing
the risk of
Keep eggs refrigerated.
Discard cracked or dirty eggs.
Wash hands and cooking utensils with soap and water after
contact with raw eggs.
Eat eggs promptly after cooking.
Do not keep eggs warm for more than two hours.
Refrigerate unused or leftover egg-containing foods.
Avoid eating raw eggs (as in homemade ice cream or eggnog).
Commercially manufactured ice cream and eggnog are made with
pasteurized eggs and have not been linked with
Avoid restaurant dishes made with raw or undercooked,
unpasteurized eggs. Restaurants should use pasteurized eggs in any
recipe (such as Hollandaise sauce or caesar salad dressing) that
calls for pooling of raw eggs.
Centers for Disease Control and
Prevention, April 2001
Please be aware that this information is provided to supplement the care
provided by your physician. It is neither intended nor implied to be a
substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER
IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the
advice of your physician or other qualified health provider prior to
starting any new treatment or with any questions you may have regarding a