Food Borne Illness

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

Bacterial Food Poisoning Toxins that are destroyed by heating Clostridium botulinum Toxins that are destroyed by heating Clostridium botulinumClostridium botulinumClostridium botulinum Heat stable toxins Produced by bacteria Staphylococcus aureus Clostridium perfringens Bacillus cereus Heat stable toxins Produced by bacteria Staphylococcus aureus Clostridium perfringens Bacillus cereusStaphylococcus aureusClostridium perfringensBacillus cereusStaphylococcus aureusClostridium perfringensBacillus cereus

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

Staphylococcus aureus Staphylococcus aureus Staphylococcal Infections Gram-positive cocci in irregular clustersGram-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 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: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. Leukocidin: Destroys phagocytic white blood cells. Exfoliative toxin: Responsible for scalded skin syndrome. Exfoliative toxin: Responsible for scalded skin syndrome. Enterotoxins: Affect gastrointestinal tract. Enterotoxins: Affect gastrointestinal tract. S. aureus is commonly found in nasal passages.S. aureus is commonly found in nasal passages.

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

On Manitol salt agar Heamolysis on HBA

Staph Poisoning in USA 2000 Principal symptoms Principal symptoms Nausea, vomiting, retching, abdominal cramps, prostrationNausea, vomiting, retching, abdominal cramps, prostration Potential food contamination Potential food contamination Meat and meat products, poultry, eggMeat and meat products, poultry, egg salads (chicken, potato, macaroni),salads (chicken, potato, macaroni), cream-filled bakery products, milk and dairy productscream-filled bakery products, milk and dairy products No. of illnesses No. of illnesses 185,060185,060 No. of deaths No. of deaths 2

Micro & Macroscopic C. perfringens NOTE: Large rectangular gram-positive bacilli Inner beta-hemolysis = θ toxin Outer alpha-hemolysis = α toxin NOTE: Double zone of hemolysis

Clostridial Cellulitis

Exotoxins Associated with C. perfringens Types A-E Major

Perfringens Poisoning in USA 2000 Principal symptoms Principal symptoms Intense abdominal cramps, diarrhea Potential food contamination Potential food contamination Meat, meat products, gravies Meat, meat products, gravies No. of illnesses No. of illnesses 248, ,520 No. of deaths No. of deaths 7

Clostridium perfringens Two syndromes – diarrhoea and ‘ pig-bel ’ (necrotizing enteritis) The organism – large, non- motile G+ve, anaerobic rod - bacillus 2 forms – vegetative and spore- forming Strains – Type A (diarrhoea) - Type C ( ‘ pig-bel ’ )

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

Clostridium botulinum Botulism & infant botulism (& wound botulism) The organism – anaerobic, G+ve, spore-forming rod

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

Clostridium botulinum Characteristics - grows anaerobically - spores & toxin resist freezing - spores resist desiccation

Clostridium botulinum Pathogenesis - neurotoxin inhibits acetylcholine release - ultimately affects peripheral NS

Clostridium botulinum Botulinum toxin inhibits acetylcholine release at neuromuscular junction

Clostridium botulinum The illness, continued - infective dose – few nanograms - all individuals susceptible; infants <1yr - Rx – toxin removal, supportive Rx

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)

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

Bacillus cereus Principal symptoms Principal symptoms Diarrheal—watery diarrhea, abdominal cramps and painDiarrheal—watery diarrhea, abdominal cramps and pain Emetic—nausea and vomitingEmetic—nausea and vomiting Potential food contamination Potential food contamination Meats, milk, vegetables, fish 0Meats, milk, vegetables, fish 0 No. of illnesses No. of illnesses 27,36027,360 No. of deaths 0

Bacillus cereus Two syndromes – diarrhoeal & emetic The organism – G+ve spore- forming rod Toxins – diarrhoeal & emetic

Bacillus cereus Characteristics - rapid growth in food at C - vegetative cells killed by heat - spores resistant, emetic toxins resistant to heat