Louise Margaret Tomas
SCB 260.7733
Professor I. Grozav
Fall 2007 Session II
Disease Report:
Staphylococcal Food Poisoning
(Gram Positive)
Etiologic agent:
The Gram positive bacterium Staphylococcus aureus is responsible for what is
known as Staphylococcal Food Poisoning.
Mode of Transmission:
Foods that are frequently a problem with staphylococcal food poisoning include
meat and meat products; poultry and egg products; salads such as egg, tuna, chicken,
potato, and macaroni; bakery products such as cream-filled pastries, cream pies, and
chocolate éclairs; sandwich fillings; and milk and dairy products. Foods that require
considerable handling during preparation and that are kept at slightly elevated
temperatures after preparation are frequently involved in staphylococcal food poisoning.
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S. aureus may also be present in raw milk and raw milk products. S. aureus can
cause mastitis in dairy cows, and other infections in meat animals. In this way, such meat
sources may cause staph outbreaks in people. Staphylococci exist in air, dust, sewage,
water, milk, and food or on food equipment, environmental surfaces, humans, and
animals. Humans and animals are the primary methods of transport. Staphylococci are
present in the nasal passages and throats and on the hair and skin of 50 percent or more of
healthy individuals. This incidence is even higher for those who associate with or who
come in contact with sick individuals and hospital environments. Although food handlers
are usually the main source of food contamination in food poisoning outbreaks,
equipment and environmental surfaces can also be sources of contamination with staph.
People can contract the illness by eating food that is contaminated with any one of many
strains of staph, usually because the food has not been kept hot enough or cold enough.
Staph bacteria grow and reproduce at temperatures from 50 degrees F to 120 degrees F,
with the most rapid growth occurring near body temperature (about 98 degrees F).
Pathogenesis:
S. aureus bacteria grow and reproduce at temperatures from 50 degrees F to 120
degrees F, with the most rapid growth occurring near body temperature (about 98 degrees
F). The toxin produced by staph bacteria is very heat-stable - it is not easily destroyed by
heat at normal cooking temperatures. The bacteria themselves may be killed, but the
toxin remains. This helps in propagating the illness of Staphyloccal food poisoning.
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Clinical findings and lesions:
Staphylococcal toxins are fast acting, sometimes causing illness in as little as 30
minutes. Symptoms usually develop within one to six hours after eating contaminated
food. Patients typically experience several of the following: nausea, vomiting, stomach
cramps, and diarrhea. The illness is usually mild and most patients recover after one to
three days. In a small minority of patients the illness may be more severe.
Diagnosis:
Toxin-producing Staphylococcus aureus can be identified in stool or vomit, and
toxin can be detected in food items. Diagnosis of staphylococcal food poisoning in an
individual is generally based only on the signs and symptoms of the patient. Testing for
the toxin-producing bacteria or the toxin is not usually done in individual patients.
Testing is usually reserved for outbreaks involving several persons. If you think you may
have food poisoning, contact your physician
Treatment:
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For most patients, staphylococcal food poisoning will cause a brief illness. The
best treatments for these patients are rest, plenty of fluids, and medicines to calm their
stomachs. Highly susceptible patients, such as the young and the elderly, are more likely
to have severe illness requiring intravenous therapy and care in a hospital. Antibiotics are
not useful in treating this illness. The toxin is not affected by antibiotics.
Prevention/ control methods:
It is important to prevent the contamination of food with Staphylococcus before
the toxin can be produced.
Wash hands and under fingernails vigorously with soap and water before handling and
preparing food.
Do not prepare food if you have a nose or eye infection.
Do not prepare or serve food for others if you have wounds or skin infections on your
hands or wrists.
Keep kitchens and food-serving areas clean and sanitized.
If food is to be stored longer than two hours, keep hot foods hot (over 140°F) and cold
foods cold (40°F or under).
Store cooked food in a wide, shallow container and refrigerate as soon as possible.
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(Picture of cocci)
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