food posisoning ppt

1. Food Poisoning
Presented by: Saundarya Deepak
JSS MEDICAL COLLEGE,MYSORE

2. Food Poisoning
Food poisoning is defined as food borne illness that is
acquired through ingestion of food contaminated with
pathogenic microorganisms,which can be either
bacterial and non bacterial toxins.
OR
Food poisoning is the acute manifestation of diarrhea
or vomiting caused by toxins produced by
microorganisms.

3. Epidemiology
• An estimated 600 million – almost 1 in 10 people in
the world – fall ill after eating contaminated food .
• 420 000 die every year, resulting in the loss of 33
million healthy life.
• Children under 5 years of age constitute 40% of the
food borne disease, with 125 000 deaths every year.

4. Classification of food borne
diseases
Food borne diseases are classified
into:
1. Food borne infections and
2. Food borne intoxications

5. 1. Food borne infections :
Infective doses of microorganisms are
ingested with food .
2. Food borne intoxications:
Preformed toxin ingested with food.

6. Food borne infections

7. Food borne infections
• Food borne infections are caused by the entry of
pathogenic microorganisms contaminating food into
the GIT.
• long incubation periods.
• Characterized by fever.
• Either be fungal, bacterial, viral or parasitic.

8. Food Borne Infections types
BACTERIAL
• Salmonellosis
• Campylobacteriosis
• Escherichia coli infection
• Shigellosis
• Cholera
• Vibrio parahemolyticus
• Vibrio vulnificus
• Yersiniosis
Fungal
• Aspergillus species
PARASITIC
• Cryptosporodiosis
• Giardiasis
VIRAL
• Hepatitis A
• Norwalk like virus

9. Salmonellosis
• Food poisoning caused by consumption of food
contaminated with Non typhoidal Salmonella.
Salmonella typhimurium Salmonella newport.
Salmonella enteritidis Salmonella softenburg
Salmonella choleraisuis Salmonella infantis
• A heavy dose up to 10,000 -1,000,000 bacilli per
gram of food is required to cause infection.
• Incubation period is 12 -24 hours.

10. Transmission
1. Consumption of contaminated food from carriers,
from human excreta.
2. Transferred to food through hands, utensils,
equipments, flies etc.
3.Presence of flies, cockroaches, rats, in the food
environment that act as vectors of the disease.

11. Clinical Features
• Fever
• diarrhea
• vomiting
• abdominal pain
• headache
• prostration and
• malaise.
• In severe cases
– septicaemia
– Leucopenia
– endocarditis
– pericarditis.

12. Campylobacteriosis
• Campylobacter jejuni and Campylobacter coli cause
food poisoning and are associated with acute
enterocolitis in man.
• Campylobacter jejuni occur in large numbers in cattle
feces, and poultry as normal flora.
• Campylobacter coli are commonly associated with
human diarrhoea.
• Incubation period ranges between 2-11 days.

13. • Fever
• Diarrhoea with blood and mucous
• Abdominal pain
• Nausea
• Vomiting.
• The jejunum, ileum and colon are primarily affected
resulting in acute inflammation and abscess
formation.
• The disease is self-limiting.
Clinical features

14. Transmission
• Infection occurs by ingestion of contaminated
food-stuffs:
–meat from infected animals(poultry)
–unpasteurized milk and
–possibly cross-contamination from these
sources to foods eaten uncooked or
unrefrigerated.

15. Escherichia coli food borne
infection
• Escherichia coli are potential food poisoning
pathogens which are widely distributed.
• E. coli strains involved in food borne infection
fall into the following groups:
1. Enteropathogenic E. coli (EPEC),
2. Enterotoxigenic E. Coli (ETEC),
3. Enteroinvasive E. coli (EIEC) and
4. Enterohemorrhagic E. coli (EHEC).

16. Enterotoxigenic E.coli food borne
infection
• Main cause of endemic diarrhea in developing
countries.
• ETEC produce two toxins which may be labile toxin
(LT) or Stable toxin(ST) or both.
• It is toxigenic but not invasive type.
• Transmission is by contaminated food and water.

17. Clinical features
Common features
• profuse, watery diarrhea
with no blood
• abdominal cramping.
Less common features
• Fever
• Nausea with or without
vomiting
• Anorexia
• Headache
• Muscle aches and bloating

18. Traveler's Diarrhea
• People travelling to developing countries are at
high risk of developing diarrhea.
• ETEC is the leading cause of Traveler’s
diarrhea in Asia, Africa, Latin America.
• IP- 5-15 day.

19. Enterohemorrhagic E. coli
• EHEC infection is caused by Escherichia coli
serotype O157:H7.
• Toxin is secreted called as verocytotoxin or Shiga-
like toxin.
• causes hemorrhagic colitis in humans, diarrhea,
abdominal pain, fever and vomiting.
• complications - bloody diarrhea, acute ulcerative or
ischemic colitis and HUS(Haemolytic uraemic
syndrome).

20. Shigellosis (Bacillary dysentery)
• Shigellosis is caused by members of the genus
Shigella.
– Shigella dysenteriae,
– Shigella flexneri,
– Shigella boydii and
– Shigella soneii.
• The infective dose is very small 10-100 bacilli.
• Spread is by fecal-oral route.

21. Clinical symptoms
• The illness begins 1 to 4 days after ingestion of
bacteria and may last 4 to 7 days.
• Symptoms include :
– fever,
– watery or bloody diarrhea with mucous,
– nausea or vomiting,
– abdominal pain,
– dehydration

22. Cholera
• Cholera is caused by Vibrio cholera.
• Vibrios are ingested in drink or food.
• The organism multiply in the small intestine
to produce a very potent enterotoxin, which
stimulates a persistent out pouring of isotonic
fluid by the gut mucosal cells.

23. Transmission
• Man is the only natural host of the cholera vibrios.
• Spread of infection is from person-to-person,
through contaminated water or foods.
• Shrimps, contaminted water, shellfish and
vegetables are the most frequent carriers.

24. Clinical symptoms
• Cholera is typically characterized by the sudden onset
of effortless vomiting and profuse watery diarrhea
mucous flakes.
• 20-30 stools per day
• Death may occur in 12 to 24 hrs due to rapid
dehydration and hypovolemic shock.

25. Vibrio parahemolyticus
• Vibrio parahemolyticus is a pathogenic bacteria
causing food borne infections, whose natural habitat
is the sea.
• Human infections occur solely from sea foods such as
oysters, shrimps, crabs, lobsters, fish,clams and
related shellfish.

26. Clinical features
• V.parahemolyticus causes gastro-enteritis and extra
intestinal infections in man.
• The incubation period is 16 hrs
• Symptoms include:
a. Diarrhea e. Vomiting
b. Cramps f. Headache
c. Weakness g. Chills
d. Nausea

27. Vibrio vulnificus foodborne infection
• Vibrio vulnificus causes a severe foodborne infection,
often associated with eating raw oysters.
• In immuno-compromised hosts, V. vulnificus infections
can cause fever, nausea, myalgia and abdominal cramps.
• IP- 24-48 hours.

28. Yersinia enterocolitica infection
• This organism has been isolated from beef,
lamb, pork, sea foods, vegetables milk and
cakes, vacuum-packed meat.

29. • Symptoms includes:
• Fever
• Diarrhea
• Abdominal cramps
• Vomiting
• Headache
• The organism is shed in stools up to 40 days
following illness.
Clinical Features

30. VIRAL FOODBORNE INFECTIONS
• Viruses are common pathogens transmitted
through food.
• Hepatitis A and Norwalk-like virus
(Norovirus) are the most important viral food
borne pathogens.
• These viruses are highly infectious and may
lead to widespread outbreaks

31. Hepatitis A
• Incubation period is long, average of 30 days.
– Fever
– Muscle aches
– Headache
– Loss of appetite
– Abdominal discomfort
– Weakness and fatigue

32. Norwalk-like virus (Norovirus)
• Infection is mild, incubation period of 3 days.
• Consumption of raw oysters.
• Clinical manifestations include: vomiting and
diarrhea, and rarely convulsions.

33. FOOD BORNE
INTOXICATIONS

34. FOOD BORNE INTOXICATIONS
These are diseases caused by consumption of food
containing:
1. Biotoxicants : which are found in tissues of certain
plants and animals. Eg- Mushroom toxicity.
2. Metabolic products (toxins): formed and excreted
by microorganisms, while they multiply in food, or in
gastrointestinal tract of man.
3. Poisonous substances: which are present in the food
during production, processing, transportation or
storage.

35. Food borne intoxications……
Food borne intoxications have short incubation
periods (min to hours) and are characterized by
lack of fever.
Food borne intoxications can be classified into:
a. Bacterial intoxications
b. Fungal intoxications
c. Chemical intoxication
d. Plant toxicants, and
e. Poisonous animals.

36. BACTERIAL FOOD BORNE
INTOXICATIONS
1. Staphylococcus aureus
2. Bacillus cereus
3. Clostridium perfringens
4. Clostridium botulinum

37. Staphylococcus aureus food borne
intoxication
This is a type of food borne intoxication which is
caused by consumption of food contaminated
with staphylococcal enterotoxin produced by the
certain strains of Staphylococcus aureus.

38. The five enterotoxins are:
Staphylococcal enterotoxinA
Staphylococcal enterotoxin B
Staphylococcal enterotoxin C
Staphylococcal enterotoxin D
Staphylococcal enterotoxin E
All the five enterotoxins have the similar
potency.
Individual strains of S.aureus may produce one or
more of enterotoxin types while growing in food.

39. Toxin production
• Toxin production occurs at growth
temperature 12-44o
C, pH 4.2 and salt
concentration of ≤10%.
• No toxin production occurs at temperatures
below 12o
C, pH < 4.2 and > 10 % salt.

40. Nature of enterotoxins
• All the staphylococcal enterotoxins are heat stable
and ordinary cooking procedures, pasteurization
and drying do not inactivate these enterotoxins.
• pH stable and resistant to most proteolytic enzymes
(trypsin, chymotrypsin, renin, and pepsin).

41. Causative foods
• Milk products: Non meat products:
pasteurized milk egg
yoghurt egg products
vegetables
cereal
• Meat products :
Fish
Shellfish
Poultry

42. Clinical features
• Incubation period is 1-6 hr.
• At least 1.0 µg of enterotoxin causes infection
• nausea, vomiting, abdominal cramps,
sometimes diarrhea with prostration.
• Duration of illness is 24-72 hrs.

43. Bacillus cereus food borne
intoxication
• This is a food borne intoxication caused by
consumption of enterotoxins produced by
some strains of Bacillus cereus.
• The organism produces the following
enterotoxins
a. Two diarrhoeal enterotoxins: -
hemolysin enterotoxin,
non-hemolytic enterotoxin
a. Emetic toxin

44. Causative foods
• Meat
• Eggs
• Dairy products
• Cereal dishes e.g. rice, spice, mashed have been
involved in B. cereus poisoning.

45. Clinical manifestations
1.Emetic syndrome
• nausea
• Vomiting
• abdominal cramps
Rice and pasta based foods are involved

46. 2. Diarrheal syndrome
• profuse diarrhoea (watery stool)
• abdominal cramps
• tenesmus (rarely vomiting)
• Fever is absent.
Meat, vegetables ,dried beans and cereals

47. Clostridium perfringens food borne
intoxication
• food borne intoxication caused by C perfringens
enterotoxin (CPE) produced in the GIT by
enterotoxigenic strains of C. perfringens.
• found in the soil, dust, water, sewage marine
sediments, decaying materials, GI tracts

48. Cause of intoxication
• ingestion of contaminated food with large numbers of
C. perfringens type A & some type C and D
• The food poisoning strains are heat resistant and survive heating
at 100o
C for 1 hr.
• Foods poisoning occurs when the level reaches 107
-108
cells/g of
food

49. Causative foods
• Red meats, chickens, fish, pork, fruits, vegetables.
• Contamination of slaughter meat from containers,
handlers, dust, and water.
• The food involved are those that are prepared one day
and served the next day.
• The heating of such foods is inadequate to destroy heat
resistant endospores.

50. Clinical features
• IP- 8-24 hours after ingestion
• Symptoms include nausea, intestinal cramps,
pronounced diarrhea,
• Vomiting is rare and the illness takes a
duration of 1-2 days.

51. Clostridium botulinum foodborne
Intoxication• Botulism is a type of food poisoning caused by
consumption of enterotoxins produced by strains of
Clostridium botulinum.
• Intoxication is caused by toxins A, B,C1,C2,D,E, F & G.
• Spores of C. botulinum type A can survive temperatures of
120o
C.
• Type E strains are non-proteolytic while the rest are
proteolytic.

52. Growth characteristics
• Toxin production occurs at temperature range
between 25-30o
C.
• Proteolytic strains produce an active botulinal
toxin, while non-proteolyic strains produce
inactive pro-toxin that require activation by
trypsin.
Non-proteolytic strain Inactive pro-toxin
Active Toxin
TRYPSIN

53. Characteristic of Botulinal toxins
• These toxins are neurotoxins, highly toxic, heat
labile.
• The toxins can resist the action of the gastric and
intestinal juices.
• Botulinal toxin is one of the most lethal poisons
known.
• The calculated lethal dose for an adult person is
10 µg.

54. Types of foods implicated
• Foods associated with anaerobic conditions such as
spoiled canned meat, or hams and bacon stacked
without air access, are particularly liable to be
infective.
• Uncooked fresh foods are safe because they are eaten
before the toxin has had time to develop.

55. Clinical features
Adult botulism
• The period of incubation in man is 12-72 hrs.
• Nausea headache
Vomiting dryness of skin
Fatigue respiratory failure
Dizziness lack of fever,
Nerve paralysis double vision
• Duration of illness 1-10 days.

56. Infant botulism
• Occurs in infants less than 1 year of age through
ingestion of spores in honey.
• The spores germinate in the GIT with toxin production.
• A high number of spores are found in feces of infants
during acute phase of the disease.
• Constipation,poor feeding,lethargy,weakness, floppiness

57. Fungal intoxications
• These are caused by consumption of metabolites
called as mycotoxins produced by fungi, while
growing in food.
• Grains(Poor dry storage), oilseeds, fruits and
vegetables are mostly involved.
• Of significance to public health is aflatoxicosis.

58. Aflatoxicosis
• Aflatoxicosis is caused by Aflatoxins produced by the
fungi, e.g. Aspergillus flavus and Aspergillus
parasiticus
• Four types of aflatoxins have been described i.e.
aflatoxin B1, B2, G1 and G2.

59. Effects of aflatoxins
• large doses are lethal : acute hemorrhagic
syndromes.
• Medium doses are sub-lethal : histotoxic
changes.
• small doses for long term : liver tumors as
these are potent carcinogens.

60. CHEMICAL FOODBORNE
INTOXICATION
• This is a type of food borne intoxication arising from
consumption of food containing poisonous chemicals.
• These may be intentionally or unintentionally added
to foods as a result of producing, processing,
transporting or storage.

61. Chemical substances involved
Chemical food borne intoxication involve the
following substances:
• Heavy metals e.g. antimony, mercury, arsenic,
flouride, lead, cadmium, cyanide etc.
• Pesticides and insecticides .
• Herbicides and Fungicides.
• Radionuclides e.g. radium, barium, iodine
isotopes etc.

62. Clinical features
• very short incubation period(mins to few hrs).
• mainly involved are GIT and CNS :
– Nausea
– headache
– Convulsions
– gastrointestinal irritation
– abdominal cramps
– vomiting and diarrhea
– Pallor
– Cyanosis
– blurred vision

63. Biotoxications
• These are disorders resulting from ingestion of
a poisonous substance (a biotoxin) present in
the body of a plant or animal.
• derived from plants or animals as a result of
metabolic activities.

64. Animal biotoxications
• This type of intoxication occurs as a result of
consumption of poisonous animals.
• One of the example is puffer fish, a delicacy of
China.

65. Clinical Diagnosis
• Specimen collection:
feces/stool
left-over food
vomitus
• Microscopy: Microscopy of faeces is done to detect motility
of the organism ,and ova or cyst of parasite.
Wet mount
hanging drop
staining.
• Culture: Selective & non-selective medias are used
according to the suspected organism.

66. • Salmonella & Shigella-
– XLD(xylose lysine deoxycholate )
– HEA(hekton enteric agar)
– SSA(salmonella shigella agar)
– WB(wilson blair)
– Buffered gycerol saline.
• Vibrio cholerae-
– Alkaline peptone water
– TCBS(thiosulfate citrate bile sucrose)
– Cary blair
• Staphylococcus aureus-
– Mannitol salt agar
– Milk salt agar

67. • Bacillus cereus-
• MYPA(mannitol egg yolk phenol red polymyxin agar)
• PEMBA(polymyxin B egg yolk mannitol bromothymol blue agar).
• Anaerobes-
• RCMB(robertson cooked meat broth).
• Thioglycollate broth.
• Campylobacter-
• Skirrows
• Butzler
• campy

68. Microscopy light microscopy
electron microscopy
stool
culture
Food tissue culture
poisoning
toxin assay
serology
ELISA,LAT,Eletrophoresis
P.C.R. – Specific identification
Parasite(ova,cyst)
Hanging drop
Gram stain
Ziehl-Neelsen stain
virus
Direct
Enrichment
Selective
Virus
Mac Conkey
Selenite FB, Tetrathionate
Alkaline peptone water
Wilson blair, TCBs, XLD,
DCA
Identification
Serotyping
Antibiotic sensitivity
&
Biochemical reaction

69. • Serological Diagnosis: detection of toxin
ELISA
LAT
Electrophoresis
• Molecular techniques: Polymerase chain reaction

70. Preventive Measures
• Regular hand-washing
• Sanitary improvements.
• Health Education: Food handler should be educated in
matter of the clean habits, and personal hygiene.
• fast cooling of food so that the remaining spores might
not germinate.
• Thorough washing and sanitation of containers while
handling food items.

71. Bibliography
• Textbook of Microbiology by Ananthnarayan and
Paniker’s:9th
edition.
• Essentials of medical microbiology by Apurba Sankar
Sastry.
• Principles and practice of infectious diseases by John
E. Bennet, Raphael Dolin and Martin J.Blaser :8th
edition.
• Diagnostic Microbiology by Bailey and Scott’s :12th
edition.

72. THANK
YOU