FOOD BORNE DISEASES

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FOOD BORNE DISEASES

• Moderator Dr B S Garg
• Presenter - Dr Gaurij Hood

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Food borne Diseases

• 1.Introduction
• 2.Pathogenesis and Transmission
• 3.Important foodborne pathogens/toxins/chemicals
• 4.Investigations and Lab diagnosis
• 5.Treatment and Prevention

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1.Introduction

• Food borne diseases-(intoxications and
  infections) Covers illnesses acquired through
  consumption of contaminated food-food poisoning
• Food borne disease outbreaks-
• Occurrence of 2 or more cases of similar
  illness resulting from ingestion of common food
• OR
• When observed number of paticular disease
  exceeds expected number

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1.Introduction

• Global burden- high morbidity and mortality
• Infectious diarrhoea- 3 to 5 billion cases and
  1.8 million deaths annually
• CDC- 76 million cases of food borne diseases in
  US annually with appx.5000 deaths
• In India- Integrated disease surveillance
  Project (IDSP) - Food poisoning outbreak
  reporting increased to more than double in 2009
  from 2008 (120 in 2009 and 50 in 2008)

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Food borne infections vs intoxication

• Infections
• Bacterial / Viral / parasite
• Invade and or multiply in lining of
  intestine
• Incubation period- hours to days
• S/s Diarrhoea , nausea, vomitting , abdominal
  cramps, fever
• Communicable-spreads from person to person
• Factors-inadequate cooking, cross contamination ,
  poor personal hygiene , bare hand contact

• Intoxications
• toxins ( natural / preformed bacterial /
  chemical)
• No invasion or multiplication
• Incubation period-
• minutes to hours
• S/s Vomitting , nausea, diarrhea , diplopia,
  weakness, resp. failure , numbness, sensory/motor
  dysfunction
• Not communicable
• Factors-inadequate cooking , improper handling
  temperatures

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Epidemiology in India
Agent Year Region People affected Implicated Food
Salmonella paratyphi A 1995 Yavatmal 33 Vegetarian food
Clostridium butyricum 1996 Gujarat- residential school 34 students Sevu (Gram flour crisp)
Salmonella Enteritidis 1998 Armed Forces 78 personnel Frozen fowl
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Epidemiology in India
Agent Year Region People affected Implicated Food
Norwalk like Virus 2002 Delhi Hospital 130 nurses Salad Sandwiches
Staph. Aureus 2007 MP gt100 children n adults Bhalla ( fried potato balls)
Salmonella welteverden and Wein 2008-09 Mangalore 34 and 10 Chicken and Fish
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Some important food-borne pathogens, toxins and
chemicals

• 1. Bacteria - Bacillus cereus , Brucella ,
  Campylobacter, Clostridium sp , E.coli,
  Salmonella sp , Listeria , Staph aureus , Vibrio
  cholera and V.parahemolyticus
• 2. Viruses - Hepatitis A and E , Rotavirus ,
  Norvovirus
• 3. Protozoa Cryptosporidium , Cyclospora ,
  Entamoeba , Giardia , T. gondii
• 4. Trematodes , Cestodes and Nematodes

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Food borne pathogens-toxins and chemicals

• Toxins - marine biotoxins , tetrodotoxin (puffer
  fish), pyrrolizidine alka (Endemic ascites) ,
  mushroom toxins , shellfish toxins ,
  mycotoxins-(Aflatoxins ,Ergot and Fusarium),
  plant intoxicants , BOAA (Lathyrism)
• Chemicals - pesticides (OPP,sb) , radionuclides ,
  nitrites (food preservatives) toxic metals - cd,
  cu, hg, pb, sn, fluoride , MSG

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Pathogenesis and Transmission

• Inoculum / size of infective dose -Can be as
  small as 10-100 bacterial cysts for Shigella ,
  EHEC , Giardia, E. histolytica
• or 10 5-10 8 for Vibrio cholera, variable
  for salmonella
• Animals / humans harbouring infection ? shed in
  feces ? contaminate water , fruits , vegetables
  ?inadequate cooking / improper storage ?
  infection
• Warm temperature(10-50 degree cent.)-
• multiplication of pathogens

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Some common bacterial food poisons
Incubation period Cause Symptoms Common foods
1-6 hours Staph aureus (enterotoxin) Nausea, vomitting, diarrhea Milk n milk products, ham, poultry, salads, custards
Bacillus cereus (enterotoxin) Nausea, vomitting, (emetic form) Fried rice
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Some common bacterial food poisons
Incubation period Cause Symptoms Common foods
8-16 hours Clostridium perfringes (spores) Abd.cramps, diarrhea Nausea and Vomitting -rare Meat, poultry, legumes. gravies
Bacillus cereus ( diarrheal form- preformed n stable toxins) Diarrhea, abd.pain, nausea, vomitting/fever-No

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Some common bacterial food poisons
Incubation period Cause Symptoms Common foods
gt16 hours Vibrio cholera Rice watery stools Water and ice creams, sea food
Salmonella spp Inflammatory diarrhea Meat , milk n milk products, poultry
Shigella sp dysentry Potato/raw eggs-salad
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Early diagnosis and investigations

• 1.Initial assessment of cases
• Detailed clinical history including time
  of onset , duration of illness , symptoms , h /o
  travel , recent meals , cooking and refrigeration
  , details of others with similar complaints
• 2.Detailed clinical examination
• Vitals and degree of dehydration ,
  systemic signs

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Lab diagnosis

• Main objectives-
• a) To confirm clinical diagnosis by isolation
  of causative agent from proper samples ,
• eg . stool , vomitus / gastric aspirate ,
  food specimens
• b) Ensure proper identification of disease
• c) Determine causative agent if present in food
  sources with relevant epidemiological markers-
  eg. Biotyping , serotyping , PCR , Phage typing
  etc

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Collection of food samples

• Using aseptic technique n appropriate containers
  ? samples be refrigerated during storage and
  transport ? must arrive lab within 3 days of
  collection
• Adequate sample - minimum 100 grams
• Containers - not to be filled gt75 of capacity
• Proper labelling is utmost important ? labelled
  specimen be placed in zip lock bag and sealed
• Vaccine carrier with ice packs for transport and
  cold chain maintenance ( avoid freezing )

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Steps of outbreak investigation
Establishing existence
Co-ordination
Collection and transport
Lab testing
Control and preventive measures
Definition of cases, population
Description of epidemiology
Possible hypotheses
Epidemiological study
Analysis of data and interpretation
Reporting
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Treatment

• 1. Initial T/t - Assessment and reversal of
  dehydration ( ORT / IV Fluids )
• 2. Cause specific treatment if any- eg.
  chelating agents in case of pesticide poisoning
• 3. Use of antibiotics can be considered if
  bacterial cause is identified

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Steps of outbreak investigation

• Establishing existence of outbreak(detailed
  baseline epidemiological information)?Co-ordinatio
  n with key personnel?Collection and transport of
  clinical specimens and food samples for lab
  testing?Implementation of control and preventive
  measures?definition of cases,population at risk
  and finding cases?Description of
  epidemiology?Development of possible
  hypotheses?Epidemiological study to evaluate
  hypotheses?Analysis of data and
  interpretation?Reporting findings of outbreak
  investigation

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Prevention in community

• Proper handwashing and personal hygiene
• Proper storage (refrigeration)
• Food saftey education community and food
  handlers
• Environmental measures - Discourage sewage
  farming for growing fruits and vegetables

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Prevention

• Hazard Analysis and Critical Control Point
  (HACCP) -
• Systematic preventive approach to food safety
• Addresses physical , chemical and biological
  hazards as means of prevention rather than
  finished product inspection
• Food industry - Food safety hazards identified at
  all stages of food production and preparation
  processes ? key action taken at Critical Control
  Points (CCP s)

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Principles of Hazard Analysis and Critical
Control Point ( HACCP )

• Analyse hazards ? Identify critical control
  points ? Establish preventive measures with
  critical limits for each CCP ? Establish
  procedures to monitor CCPS ? Establish corrective
  actions when monitoring shows that critical limit
  has not met ? Establish procedures to verify that
  system is working properly ? Establish effective
  record keeping for documentation

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Safety Regulations

• Prevention of Food Adulteration Act , 1954-
• To Ensure pure and wholesome food and to
  protect from fradulent practices
• Amendments -1964,1976,1986
• Case of proven adulteration Minimum imprisonment
  of 6 months and minimum fine of Rs 1000 envisaged
• Grievous Hurt-(320 IPC)- Death or such harm can
  be punished upto Life imprisonment and fine not
  ltRs 5000
• Food Standards- Codex Alimentarius , Agmark
  standards,
• Bureau of Indian Standards
• National Nutrition Policy -1993- Food Security

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Five keys to Safer food

• 1. Keep Clean
• Wash hands before handling food and often
  during
• preparation
• Wash hands after going to toilet
• Wash n sanitise all surfaces n equipment for
  food preparation-protect kitchen from insects ,
  pets
• 2. Separate raw and cooked food-
• Separate raw meat , poultry n seafood from
  other foods
• Use separate utensils for handling raw foods
• Store food in containers to avoid contact
  between raw and cooked foods

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Five Keys to Safer Food

• 3. Cook Thoroughly
• esp. Meat , poultry , eggs and Seafood
• Bring soups n stews to boiling
  (ensuregt70degree temp)
• Reheat cooked food thoroughly
• 4. Keep food at safe temperature -
• Dont leave cooked food at room temp.gt2 hours
• Prompt refrigeration of cooked n perishable
  food
• Keep cooked food piping hot(gt60 de.) prior
  to serving
• Dont store food too long even in
  refrigerator
• Dont thaw frozen food at room temperature

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Five keys to safer food

• 5. Use safe water and raw materials-
• Use safe water or treat to make it safe
• Select fresh and wholesome fruits
• Choose foods processed for safety - pasteurised
  milk
• Wash fruits n vegetables if eaten raw
• Dont use food beyond expiry date

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References

• 1. CD Alert December 2009, vol.13No.4
  Food Borne
• Diseases, page no. 1-12
• 2.Parks Textbook of PSM , Twentieth Edition,
  Intestinal
• infections Food Poisoning , page no.
  210-212
• 3.Internet- www.nicd.nic.in

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• THANK YOU