Food Borne Illness

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Food Borne Illness
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Food Borne Illness

• Food Borne Illness Can be caused by
• Food Borne Infections ( Living organisms )
• Food Borne Toxins ( non living chemicals )
• Food Poisoning
• Food Borne Toxins ( non living chemicals )
• Generated by Microbes
• Bacteria
• Fungi
• Algea
• Man made toxins
• Agricultural residues
• Antibiotics
• Preservatives
• Naturally occuring toxins

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Bacterial Food Poisoning

• Toxins that are destroyed by heating        
  Clostridium botulinum
• Heat stable toxins         Produced by bacteria
             Staphylococcus aureus           
  Clostridium perfringens            Bacillus
  cereus

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Food Borne Infections

• Causes by Bacteria that must grow in food before
  eaten
• Require large infective dosage
• Only Bacteria
• Caused by Organism that do not have to grow in
  the food before it is eaten
• Require small infective dosage
• Bacteria
• Viruses
• Parasites

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Staphylococcus aureus

• Staphylococcal Infections
• Gram-positive cocci in irregular clusters
• Coagulase negative strains make up to 90 of skin
  microbiota (S. epidermidis). Only pathogenic
  when skin is broken or through invasive entry.
• Coagulase positive strains tend to be pathogenic.
  Almost all pathogenic S. aureus strains make
  coagulase. High correlation between ability to
  produce coagulase and production of damaging
  toxins
• Leukocidin Destroys phagocytic white blood
  cells.
• Exfoliative toxin Responsible for scalded skin
  syndrome.
• Enterotoxins Affect gastrointestinal tract.
• S. aureus is commonly found in nasal passages.

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Staphylococcal Food Poisoning

• Characteristics
• Acute onset of cramps, vomiting, nausea,
  occasional diarrhea, low body temperature and
  blood pressure.
• Recovery is usually complete within 24 hours.
• Mortality is low in healthy individuals, higher
  among immunosuppressed individuals.
• Pathogens S. aureus strain that produces an
  enterotoxin.
• Reservoir Human skin, nasal secretions, and cow
  milk.

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• On Manitol salt agar

Heamolysis on HBA
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Staph Poisoning in USA 2000

• Principal symptoms
• Nausea, vomiting, retching, abdominal cramps,
  prostration
• Potential food contamination
• Meat and meat products, poultry, egg
• salads (chicken, potato, macaroni),
• cream-filled bakery products, milk and dairy
  products
• No. of illnesses
• 185,060
• No. of deaths
• 2

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Micro Macroscopic C. perfringens
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Clostridial Cellulitis
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Exotoxins Associated with C. perfringens
Types A-E
Major
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Perfringens Poisoning in USA 2000

• Principal symptoms
• Intense abdominal cramps, diarrhea
• Potential food contamination
• Meat, meat products, gravies
• No. of illnesses
• 248,520
• No. of deaths
• 7

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Clostridium perfringens

• Two syndromes diarrhoea and pig-bel
  (necrotizing enteritis)
• The organism large, non-motile Gve, anaerobic
  rod - bacillus
• 2 forms vegetative and spore-forming
• Strains Type A (diarrhoea)
• - Type C (pig-bel)

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Clostridium botulinum

• Principal symptoms
• Weariness, weakness, vertigo, double vision,
  difficulty swallowing and speaking
• Potential food contamination
• Improperly canned or fermented goods
• No. of illnesses
• 58
• No. of deaths
• 4

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Clostridium botulinum

• Botulism infant botulism
• ( wound botulism)
• The organism anaerobic, Gve, spore-forming rod

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Clostridium botulinum

• Group I type A, B F food spoilage
• Group II type B, E F
  
• Types A, B, E F human botulism
• Types C D botulism in animals

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Clostridium botulinum

• Characteristics
• - grows anaerobically
• - spores toxin resist freezing
• - spores resist desiccation

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Clostridium botulinum

• Pathogenesis
• - neurotoxin inhibits
  acetylcholine
• release
• - ultimately affects peripheral NS

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Clostridium botulinum

• Botulinum toxin inhibits acetylcholine
  release at neuromuscular junction

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Clostridium botulinum

• The illness, continued
• - infective dose few nanograms
• - all individuals susceptible infants
  lt1yr
• - Rx toxin removal, supportive Rx

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Clostridium botulinum

• Sources
• - human no
• - animal can be affected
• - food Type E in seafood, Type A in
• vegetables, honey
• - environment Types A, B F in
• 
  soils/sediments
• Type E
  marine
• Dust
  (vacuum cleaner)

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Clostridium botulinum

• Outbreaks/sporadic cases
• Very rare in NZ one case in 1984
• puha mussels (incomplete lactic acid
• 
  fermentation)
  
• Overseas
• - roasted egg plant in oil, chopped
  garlic in oil,
• salted fish, tinned salmon, yoghurt,
  cheese
• cheese sauce

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Bacillus cereus

• Principal symptoms
• Diarrhealwatery diarrhea, abdominal cramps and
  pain
• Emeticnausea and vomiting
• Potential food contamination
• Meats, milk, vegetables, fish 0
• No. of illnesses
• 27,360
• No. of deaths
• 0

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Bacillus cereus

• Two syndromes diarrhoeal emetic
• The organism Gve spore-forming rod
• Toxins diarrhoeal emetic

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Bacillus cereus

• Characteristics
• - rapid growth in food at 30-400C
• - vegetative cells killed by heat
• - spores resistant, emetic toxins
• resistant to heat