Links to Other Disorders
Common Sources of Foodborne Illness
Points To Remember
Foodborne illness results from eating food contaminated with bacteria (or
their toxins) or other pathogens such as parasites or viruses. The illnesses
range from upset stomach to more serious symptoms, including diarrhea, fever,
vomiting, abdominal cramps, and dehydration. Although most foodborne infections
are undiagnosed and unreported, the Centers for Disease Control and Prevention
estimates that every year about 76 million people in the United States become
ill from pathogens in food. Of these, up to 5,000 die.
Harmful bacteria are the most common causes of foodborne illnesses. Some
bacteria may be present on foods when you purchase them. Raw foods are not
sterile. Raw meat and poultry may become contaminated during slaughter.
Seafood may become contaminated during harvest or through processing. One
in 20,000 eggs may be contaminated with Salmonella inside the egg shell.
Produce such as lettuce, tomatoes, sprouts, and melons can become contaminated
with Salmonella, Shigella, or Escherichia coli (E. coli) O157:H7. Contamination
can occur during growing, harvesting, processing, storing, shipping, or
final preparation. Sources of contamination are varied; however, these items
are grown in the soil and therefore may become contaminated during growth
or through processing and distribution. Contamination may also occur during
food preparation in the restaurant or in the person's kitchen.
When food is cooked and left out for more than 2 hours at room temperature,
bacteria can multiply quickly. Most bacteria grow undetected because they
do not produce an "off" odor or change the color or texture
of the food. Freezing food slows or stops bacteria's growth but does not
destroy the bacteria. The microbes can become reactivated when the food
is thawed. Refrigeration may slow the growth of some bacteria, but thorough
cooking is needed to destroy the bacteria.
In most cases of foodborne illness, symptoms resemble intestinal flu and
may last a few hours or even several days. Symptoms can range from mild
to serious and include:
Some people are at greater risk for bacterial infections because of their
age or immune status. Young children, pregnant women and their fetuses,
the elderly, and people with lowered immunity are at greatest risk.
Some micro-organisms, such as Listeria monocytogenes and Clostridium botulinum,
cause far more serious illness than vomiting or diarrhea. They can cause
spontaneous abortion or death.
In some people, especially children, hemolytic uremic syndrome (HUS)
can result from infection by a particular strain of bacteria, E. coli
O157:H7, and can lead to kidney failure and death. HUS is a rare disorder
that affects primarily young children between the ages of 1 and 10 years
and is the leading cause of acute renal failure in previously healthy
children. The child may become infected after consuming a contaminated
food, such as meat (especially undercooked ground beef), unpasteurized
apple cider or apple juice, or raw sprouts.
The most common symptoms of infection are vomiting, abdominal pain, and
diarrhea, which may be bloody. In 5 to 10 percent of cases, HUS develops
about 2 to 6 days after the onset of illness. This disease may last from
1 to 15 days and is fatal in 3 to 5 percent of cases. Symptoms of HUS
include fever, lethargy, irritability, and pallor. In about half the cases,
the disease progresses until the kidneys are unable to remove waste products
from the blood and excrete them into the urine (acute renal failure).
A decrease in circulating red blood cells and blood platelets and reduced
blood flow to organs may lead to multiple organ failure. Seizures, heart
failure, inflammation of the pancreas, and diabetes can also result. However,
most children recover completely.
You need to see a doctor right away if you have any of the following
symptoms, with or without gastrointestinal symptoms:
Signs of shock, such as weak or rapid pulse; shallow breathing; cold,
clammy, pale skin; shaking or chills; or chest pain.
Signs of severe dehydration, such as dry mouth, sticky saliva, decreased
urine output, dizziness, fatigue, sunken eyes, low blood pressure, or
increased heart rate and breathing.
Confusion or difficulty reasoning.
Your doctor may be able to diagnose foodborne illness from a list of what
you've recently eaten and results from the proper laboratory tests. Diagnostic
tests for foodborne illness should include examination of the feces. A
sample of the suspected food, if available, can also be tested for bacteria
and their toxins as well as for viruses and parasites.
Most cases of foodborne illness are mild and can be treated by increasing
fluid intake, either orally or intravenously, to replace lost fluids and
electrolytes. In cases with gastrointestinal or neurologic symptoms, people
should seek medical attention.
In the most severe situations, such as HUS, the patient may need hospitalization
in order to receive supportive nutritional and medical therapy. Maintaining
adequate fluid and electrolyte balance and controlling blood pressure
are important. Doctors will try to minimize the impact of reduced kidney
function. Early dialysis is crucial until the kidneys can function normally
again, and blood transfusions may be needed.
Most cases of foodborne illness can be prevented through proper cooking
or processing of food, which kills bacteria. In addition, because bacteria
multiply rapidly between 40°F and 140°F, food must be kept out
of this "danger zone."
To prevent harmful bacteria from growing in food, always
Refrigerate foods promptly. If you let prepared food stand at room temperature
for more than 2 hours, it may not be safe to eat. Set your refrigerator
at 40°F or lower and your freezer at 0°F.
Cook food to the appropriate temperature (145°F for roasts, steaks,
and chops of beef, veal, and lamb; 160°F for pork, ground veal, and
ground beef; 165°F for ground poultry; and 180°F for whole poultry).
Use a thermometer to be sure! Foods are properly cooked only when they
are heated long enough and at a high enough temperature to kill the harmful
bacteria that cause illness.
Prevent cross-contamination. Bacteria can spread from one food product
to another throughout the kitchen and can get onto cutting boards, knives,
sponges, and countertops. So keep raw meat, poultry, seafood, and their
juices away from other foods that are ready to eat.
Handle food properly. Always wash your hands before touching food and
after using the bathroom, changing diapers, or handling pets, as well
as after handling raw meat, poultry, fish, shellfish, or eggs. Clean surfaces
well before preparing food on them.
Keep cold food cold and hot food hot.
Maintain hot cooked food at 140°F or higher.
Reheat cooked food to at least 165°F.
Refrigerate or freeze perishables, prepared food, and leftovers within
Never defrost food on the kitchen counter. Use the refrigerator, cold
running water, or the microwave oven.
Never let food marinate at room temperature; refrigerate it.
Divide large amounts of leftovers into small, shallow containers for quick
cooling in the refrigerator.
Remove the stuffing immediately from poultry and other meats and refrigerate
it in a separate container.
Do not pack the refrigerator. Cool air must circulate to keep food safe.
Food irradiation is the treatment of food with high energy such as gamma
rays, electron beams, or x rays as a means of cold pasteurization, which
destroys living bacteria, to control foodborne disease. The United States
relies exclusively on the use of gamma rays, which are similar to ultraviolet
light and microwaves and pass through the food leaving no residue or "radioactivity."
Food irradiation is currently approved for wheat, potatoes, spices, seasonings,
pork, poultry, red meats, whole fresh fruits, and dry or dehydrated products.
Although irradiation destroys many bacteria, it does not sterilize food.
Even if you're using food that has been irradiated by the manufacturer,
you must continue to take precautions against foodborne illness, through
proper refrigeration and handling, to safeguard against any surviving
Links to Other Disorders
Scientists suspect that foodborne pathogens are linked to chronic disorders
and can even cause permanent tissue or organ destruction. Research suggests
that when some people are infected by foodborne pathogens, the activation
of their immune system can trigger an inappropriate autoimmune response,
which means the immune system attacks the body's own cells. In some people,
an autoimmune response leads to a chronic health condition. Chronic disorders
that may be triggered by foodborne pathogens are:
Inflammatory bowel disease
Further research is needed to explain the link.
Common Sources of Foodborne
Source of illness: Raw and undercooked meat and poultry.
Symptoms: Abdominal pain, diarrhea, nausea, and vomiting.
Bacteria: Campylobacter jejuni, E. coli O157:H7, L. monocytogenes, Salmonella.
Source of illness: Raw (unpasteurized) milk and dairy products, such
as soft cheeses.
Symptoms: Nausea and vomiting, fever, abdominal cramps, and diarrhea.
Bacteria: L. monocytogenes, Salmonella, Shigella, Staphylococcus aureus,
Source of illness: Raw or undercooked eggs. Raw eggs may not be recognized
in some foods such as homemade hollandaise sauce, caesar and other salad
dressings, tiramisu, homemade ice cream, homemade mayonnaise, cookie dough,
Symptoms: Nausea and vomiting, fever, abdominal cramps, and diarrhea.
Bacteria: Salmonella enteriditis.
Source of illness: Raw or undercooked shellfish.
Symptoms: Chills, fever, and collapse.
Bacteria: Vibrio vulnificus, Vibrio parahaemolyticus.
Source of illness: Improperly canned goods, and smoked or salted fish.
Symptoms: Double vision, inability to swallow, difficulty speaking, and
inability to breathe. (Seek medical help right away!)
Bacteria: C. botulinum.
Source of illness: Fresh or minimally processed produce.
Symptoms: Diarrhea, nausea, and vomiting.
Bacteria: E. coli O157:H7, L. monocytogenes, Salmonella, Shigella, Yersinia
enterocolitica, viruses, and parasites.
Points To Remember
Foodborne illness results from eating food that is contaminated with bacteria,
viruses, or parasites.
People at greater risk for foodborne illness include young children, pregnant
women and their fetuses, the elderly, and people with lowered immunity.
Symptoms usually resemble intestinal flu. See a doctor immediately if
you have more serious problems, or if you do not seem to be improving
as you'd expect.
Treatment may range from replacement of lost fluids and electrolytes for
mild cases of foodborne illness, to hospitalization for severe conditions
such as hemolytic uremic syndrome.
You can prevent foodborne illness by taking the following precautions:
Wash your hands with hot, soapy water before preparing food and after
using the bathroom or changing diapers.
Separate raw meat, poultry, or seafood from other foods to keep these
foods and their juices away from ready-to-eat foods.
Cook foods properly and at a high enough temperature to kill harmful bacteria.
Refrigerate foods within 2 hours or less after cooking because cold temperatures
will help keep harmful bacteria from growing and multiplying.
Clean surfaces well before using them to prepare foods.