Food poisoning

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Food poisoning
Ashry Gad Mohamed Prof. of Epidemiology Medical
School, KSU
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Food borne diseases (FBDs)

• Group of illnesses acquired by ingesion of
  food containing etiologic agents in such
  quantities that they affect the health of an
  individual.
• 1-Chemical contaminants e.g. heavy metals,
  detergents, pesticides, insecticides
  drugs.etc..

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• 2-Ingestion of FOOD CONTAINING TOXIN
• Microbes produce toxin while growing in food.
• Microbes produce toxin while growing in
  environment, concentrate
• in food tissues e.g. staph. Aureus
• Ingestion of the microbes themselves may be
  harmless

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• 3-Toxins elaborated in the intestine
• e.g. Cl. Perfringes.
• 4-Bacterial infection with short incubation
  period e.g.
• V parahemolyticus
• 5-Others Botulism, E. coli..etc.

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Symptoms of Food Borne Illness

• Gastrointestinal symptoms
• Campylobacter, Salmonella, Staphylococcus,
  Escherichia coli, Clostridium botulism
• mild nausea, vomiting, diarrhea, and cramps
• Neurological symptoms
• botulism or fish poisonings
• paralysis, tremors, paresthesias, dysphagia, and
  headache
• Flu-like symptoms
• Streptococcus, Listeria
• fever, rash, sore throat, and headache

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Staphylococcal Gastroenteritis

• Cause
• Heat-stable toxin produced during growth of S.
  aureus in food
• Toxin production
• S. aureus must multiply in food to produce enough
  toxin to cause illness (gt106 CFU/gm)
• Amino acids and B vitamins needed (animal origin
  foods)
• Wide temperature range 10 46C (optimum 40
  45C)
• pH range 4.0 9.8 (homemade mayonnaise)

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• Symptoms
• Primarily abrupt onset vomiting, with severe
  nausea and cramping, diarrhea /-
• Sometimes subnormal temperature and mild
  hypotension
• Rarely fatal

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• Incubation period
• 30 minutes (or less?) to 8 hours
• Usually 2 - 4 hours
• Modes of transmission
• Ingesion of contaminated food
• Foods of animal origin
• Foods that are handled directly
• Pork products, cream-filled pastries, casseroles
• Food handlers play major role. Carriage rate 25
• Diagnosis
• Clinical or epidemiologic.
• 105 organisms per gram of incriminated food
• Culture of vomitus, stool, or food may be
  negative

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Staphylococcal Gastroenteritis
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• Reporting
• Not reportable
• Report outbreaks (gt2 cases, same source) to
  Public Health Office
• Rationale caused by poor food hygiene
  investigation may prevent further cases of
  illness
• Prevention
• S. aureus is common on human skin and in nasal
  cavity
• Food workers with purulent lesions must not
  contact food!
• Standard food hygiene time, temperature,
  cleanliness
• The bacteria is killed by cooking, the toxin is
  not!
• Reduce food handling time to absolute minimum
• Control
• Identify food source (epidemiologically)
• Investigate food preparation practices
  foodhandlers
• Treatment
• Supportive, fluids if indicated

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Perfringens Diarrhea
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Perfringens Diarrhea

• Cause
• Heat-activated spores of Clostridium perfringens
  grow in food
• C. perfringens must multiply in food to high
  numbers (gt107 CFU/gm)
• Cooking temperatures activate spores to germinate
• Doubling time 8 10 minutes (Fast!)
• Theoretically, go from 1 organism to 107 in 3.2
  hours
• Grows well in small intestine, produces toxin and
  gas
• Anaerobic, but fairly aerotolerant optimum
  growth temp gt 20C
• Symptoms
• Sudden onset colic followed by
• Profuse watery diarrhea, with severe gas
• Nausea and cramping, but no vomiting
• Rarely fatal

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• Incubation period
• 6 to 24 hours, symptoms persist 12 24 hours
• Diagnosis
• Clinical (Small bowel diarrhea GAS)
• Culture of stool and/or food may be helpful.
• Detection of enterotoxin in stool of ill persons.
• Treatment
• Supportive, fluids if indicated
• Reservior
• C. perfringens spores are common in soil, water,
  milk, dust and in human GI tract.
• Modes of transmision
• Ingestion of contaminated food by soil or faeces
  in stews meat.
• Typical foods
• Meat casseroles prepared one day served the
  next day
• Chili in a large pot ? inadequate cooling in
  fridge

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• Public Health
• Reporting
• Report outbreaks (gt2 cases, same source) to
  Public Health
• Rationale caused by poor food handling
  investigation may prevent further cases of
  illness
• Control
• Identify food source (epidemiologically)
• Investigate food preparation and holding practices

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• Prevention
• Often found in raw meat and spices
• Standard food hygiene time, temperature,
  cleanliness
• The spores are activated by cooking, then grow in
  warm food
• Serving meat dishes hot as soon as cooked.
• Reheat thoroughly that the internal
  temperaturegt75 C.
• Store in refrigerators.

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B. cereus Gastroenteritis

• Cause
• Heat-activated Bacillus cereus spores (and other
  Bacillus spp.) grow in food
• Toxin produced during growth of pathogen in food
• Toxin production
• B. cereus must multiply in food to high numbers
  (gt107 CFU/gm)
• Cooking temperatures activate spores to germinate
• Emetic Syndrome
• Very similar to Staphylococcal enterotoxin, but
  less violent
• Diarrheal Syndrome
• Very similar to C. perfringens diarrhea, but less
  gas
• Toxin not denatured even at 121C for 30 minutes

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• Symptoms
• Two separate syndromes diarrheal and emetic
• Sudden onset either colic diarrhea, or nausea
  vomiting
• Lasts less than 24 hours usually relatively mild
  illness
• Incubation period
• Emetic 1 to 6 hours Diarrheal 6 to 24 hours
• Diagnosis
• Culture of stool and/or food may be helpful
• Enterotoxin testing helps, but usually not
  available
• Treatment
• Supportive, fluids if indicated

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• Reporting
• Report outbreaks (gt2 cases, same source) to
  Public Health
• Rationale caused by poor food handling
  investigation may prevent further cases of
  illness
• Prevention
• B. cereus spores are common in soil, dust and
  water
• Often found in raw meat, milk and GRAINS
• Standard food hygiene time, temperature,
  cleanliness
• The spores are activated by cooking, then grow in
  warm food
• Control
• Identify food source (epidemiologically)
• Investigate food preparation and holding practices

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• Typical foods
• Emetic syndrome Fried or boiled rice (usually)
• Diarrheal syndrome Comminuted meats (liver
  sausage, meat loaf)
• Both Cereal foods containing starch (mashed
  potatoes, pudding)

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Botulism
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• Cause
• Heat-activated spores of Clostridium botulinum
  grow in food, wound or gut
• Toxin produced during growth of pathogen
• Symptoms
• Cranial nerve impairment and descending
  paralysis, but alert
• Vomiting, constipation or diarrhea
• US case-fatality rate 5 10, full recovery
  takes months
• Incubation period
• 12 to 72 hours, sometimes longer (several days)
• Diagnosis
• Botulinum toxin in patient or food
• Culture of stool and/or food may be helpful, but
  spores are ubiquitous
• Treatment
• Supportive, assisted ventilation, no antibiotics
  (esp. aminoglycosides)
• Adult IV antitoxin Infant botulinal immune
  globulin (investigational)

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• Public Health
• Reporting
• Reportable immediately to Public Health (even a
  single case)
• Rationale fatal disease, often caused by
  improper commercial canning, therefore large
  group outbreaks are possible
• Potential bioterrorism agent (easy to make, low
  LD50)
• Prevention
• C. botulinum spores are common in soil and water
• Often found in raw meat and vegetables
• High temperature processing, high acid, nitrite
• Control
• Identify food source (epidemiologically)
• Investigate food source and preparation practices

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• Food Science
• Toxin production
• C. botulinum must multiply in anaerobic
  conditions
• Cooking temperatures dont kill spores, but
  reduce competition
• Toxin denatured by 80C for 10 minutes, or
  boiling for 2-3 minutes
• Typical foods
• Home canned food (usually low acid meats green
  vegetables )
• Sous vide (Cook - Chill) foods
• Anaerobic Bizarreness
• Garlic in oil
• Sauteed onions
• Baked potatoes

• Fermented fish
• Homemade jerky
• Baby guts

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• The golden rules for prevention of food poisoning
• 1-Choose foods processed for safety.
• 2-Cook food thoroughly.
• 3-Eat cooked food immediately.
• 4-Store cooked food carefully.
• 5- Reheat cooked food thoroughly.

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• 6-Avoid contact between cooked and raw food.
• 7-Wash hands repeatedly. using lots of friction
• Wwarm
• Aand
• Ssoapy
• 8-Keep all kitchen surfaces meticulously clean.
  Wash dishes and utensils after contact with raw
  meat or eggs.

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• 9- protect foods from insects, rodents and other
  animals.
• 10- use safe water.
• Keep hot food hot and cold food cold.