2 Staphylococcal food poisoning
Staphylococcus A + enterotoxins
S.A will grow on aerobic and anaerobic conditions
will not compete well with other microorganisms
Staphylococcus A
Small gram-positive cocci
common in skin and nasopharynx
heat-stable enterotoxin produced by certain trains
Enterotoxin
types A,B C1,C2, D, E
type A most common in food poisoning
type A is chromosomal, type b and c encoded on mobile genetic elements
functions as a superantigen- activates general inflammatory response- major fluid loss
symptoms of Staphylococcal food poisoning
- 6 -7 h after consumption for usually 12 h
- gastroenteritis characterized by severe nausea and vomiting
- moderate diarrhea
- usually no fever
food involve with Staphylococcal food poisoning
milk products, cream puffings, custard, sandwich spreads, poultry stuffing potato salad
-post-processing contamination by humans carring s.a
control Staphylococcal food poisoning
- refrigeration for below 6-7 degrees
- cooking kills microorganisms
can tolerate 30- min of boiling
botulism
- rare, high fatality rate (25%)
- clostridium botulimn
- toxin
clostridium botulinum
- gram-positive, endospore rod, strict anaerobe, inhabitant of water and soil
- spore contaminate food before harvest or slaughter
- spores initiate growth and toxin production in improperly processed foods (spore surviving processing)
- botulism results after ingestion
botulism toxin
- known as botulin or botox
- most potent toxin
- neural toxin: causes flaccid paralysis bc of not releasing acetylcholine affect respiration and heart function
- many types, ACEF humans, CD chicken duck cattle and horses
- heat sensitive- destroyed after 10 min in 80 degrees
symptoms and treatment of botulism
- flaccid paralysis, cant contract muscles
- blurred or double vision, slurred speech and difficulty in swallowing
- difficulty in breathing respiratory failure
treatment:
- botulinm antitoxin- neutralizes toxin in the bloodstream
- mechanical respirator
food involved with botulism
- home cannned non acidic vegetable , corn and beans
- not cooked properly processed food, vaccum packed smoked and fresh fish
control for botulism
- excellent quality control of canned opearion
- boiling at 80-100 degrees for 10 min - kills toxins
clostridium perfringens
- commonly found in soil
- found in the intestine of animals but in small amounts
- found in sewage
- most common food poisoning
- nonfatal resolves without treatment
clostridium perfringens pathogenesis
- must consume a large load of c.p (>10^8)
- exotoxins produced when viable cells sporulate in the intestine
- exotoxin makes the intestinal epithelium permeable
symptoms of clostridium perfringens
- onset 7.5 h, last about 24h
- intestinal diarrhea and cramps
- no vomiting or fever
food invovled clostridium perfringens
- contamination of cooked and uncooked foods especially meat, poultry and fish
- meat cooked in large bulk, and left outside at 20 - 40 degrees with sealed container
- provides an anoxic environment for rapid growth and germination of endospores
control
measure to control contamination of cooked and uncooked foods
- sufficient cooking for thorough heat penetration, kills endospores
- rapid refrigeration to prevent growth and germination of spores
Salmonellosis - salmonella
gram negative rod
- inhabits human gut, warm-blooded animals and sewage
- 2500 strains, but S.T and S.E best known for causing salmonellosis
- fecal contamination by food handlers, passage of bacteria to meat, eggs and dairy products
- ingestion of 10^5 - 10^8 viable cells -colonization in small and large intestine leads to foodborne infection
symptoms -Salmonellosis
- 8-48 h
- sudden headache, chills, diarrhea and vomiting
- fever last for days
- disease last for 2-3 days
- asymptomatic carriers: shed bacteria in feces for weeks past recovery
food involved-salmonellosis
- custard, pies ,meringues, eggnog
- milk , milk products, meat, meat pies, curred but uncooked sausage, poultry
treatment Salmonellosis
- not necessary for Salmonellosis
- antibiotics for septicemia and typhoid fever
