Transcript Food borne Diseases

FOOD BORNE DISEASES
Dr Gaurij Hood
Food borne Diseases
1.Introduction-Global and Indian Scenario
Food borne infections vs Food Intoxications
2.Pathogenesis and Transmission
3.Some important foodborne
pathogens/toxins/chemicals
4.Investigations and Lab diagnosis
5.Treatment
1.Introduction
•
•
•
Food borne diseases-(intoxications and
infections) covers illnesses acquired through
consumption of contaminated food-i.e 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
Most cases-sporadic but need investigations
for control
1.Introduction –Burden
• 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)
Food borne infections vs
intoxication
• InfectionsBacterial/Viral/parasite
• Invade and or multiply in lining
of intestine
• Incubation period-hours to
days
• s/sdiarrhoea,nausea,vomitting,ab
dominal cramps,fever
• Transmission-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/svomitting,nausea,diarrhea,dipl
opia,weaakness,resp.failure,nu
mbness,sensory/motor
dysfunction
• Not communicable
• Factors-inadequate
cooking,improper handling
temperatures
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 parahemolyticus
• 2.viruses-hepatitis a and e,rotavirus,norvovirus,
• 3.protozoacryptosporidium,cyclospora,entamoeba,giardia,t
gondii
• 4.trematodes,cestodes and nematodes
Food borne pathogens-toxins and
chemicals
• Toxins-marine
biotoxins,tetrodotoxin(pufferfish),pyrrolizidine
alka,mushroom toxins,shellfish
toxins,mycotoxins,plant toxicants
• Chemicalspesticides(opp,sb),radionuclides,nitrites(food
preservatives),toxic metalscd,cu,hg,pb,sn,fluoride,MSG
Pathogenesis and Transmission
• Infectious agent or contaminant
• 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 or humans harbouring infectionshed
in fecescontaminate
water,fruits,vegetablesinadequate
cooking/improper storageinfection
• Warm temperature(10-50 degree cent.)multiplication of pathogens
Some common bacterial food
poisons
Incubation
period
cause
symptoms
Common
foods
1-6 hours
Staph
Nausea,vo Milk n milk
aureus(ent mitting,diarr products,ha
erotoxin)
hea
m,poultry,s
alads,custa
rds
Bacillus
Nausea,vo Fried rice
cereus(ent mitting,(em
erotoxin)
etic form)
Some common bacterial food
poisons
Incubation Cause
•
period
symptoms
Common
foods
8-16
hours
Clostridium
perfringes
(spores)
Abd.cramps,
diarrhea
Nausea and
vomitting-rare
Meat,
poultry,
legumes.
gravies
Bacillus
cereus(diarrhe
al formpreformed n
stable toxins)
Diarrhea,abd.
pain,nausea,
No
vomitting/fever
Some common bacterial food
poisons
Incubation cause
period
>16 hours Vibrio
cholera
Salmonella
spp
Shigella sp
symptoms
Common
foods
Rice watery Water and
stools
ice
creams,sea
food
Inflammato Meat,milk n
ry diarrhea milk
products,po
ultry
dysentry
Potato/raw
eggs-salad
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
Lab diagnosis
• Main objectives• a)To confirm clinical diagnosis by isolation of
causative agent from proper samples,egstool,vomitus/gastric aspirate,food
specimens
• b)Ensure proper identification of disease
• c)Determine causative agent if present in food
sources with relevant epidemiological markerseg Biotyping,serotyping,pcr,phage typing etc
Steps of outbreak investigation
• Establishing existence of outbreak(detailed baseline
epidemiological information)Co-ordination 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
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
Prevention
• Hazard Analysis and Critical Control
Point(HACCP)• Systematic preventive approach to food
saftey
• Addresses physical,chemical and
biological hazards as means of prevention
rather than finished product inspection
• Food industry-food saftey hazards
identified at all stages of food production
and preparation processeskey action
taken at Critical Control Points(CCPs)
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
Treatment
• 1.Initial t/t-Assessment and reversal of
dehydration(ORT/IV Fluids)
• 2.Cause specific treatment if anyeg.chelating agents in case of pesticide
poisoning
• 3.Use of antibiotics can be considered if
bacterial cause is identified
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 >75% 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)
•
The mainstay of treatment is adequate rehydration.
•
The treatment of cholera and other dehydrating diarrheal diseases promotion of oral rehydration solutions, efficacy of which depends on
the fact that glucose-facilitated absorption of sodium and water in the
small intestine remains intact in the presence of cholera toxin.
•
The use of oral rehydration solutions has reduced mortality due to
cholera from >50% (in untreated cases) to <1%.
•
The World Health Organization recommends a solution containing 3.5
g sodium chloride, 2.5 g sodium bicarbonate, 1.5 g potassium
chloride, and 20 g glucose (or 40 g sucrose) per liter of water.
•
Oral rehydration solutions containing rice or cereal as the
carbohydrate source may be even more effective than glucose-based
solutions, and the addition of L-histidine may reduce the frequency
and volume of stool output.
•
Patients who are severely dehydrated or in whom vomiting precludes
the use of oral therapy should receive IV solutions such as Ringer's
lactate.
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
Five Keys to Safer Food
• 3.Cook Thoroughly-esp.Meat,poultry,eggs and
Seafood
• Bring soups n stews to boiling(ensure>70degree
temp)
• Reheat cooked food thoroughly
• 4.Keep food at safe temperature
• Dont leave cooked food at room temp.>2 hours
• Prompt refrigeration of cooked n perishable food
• Keep cooked food piping hot(>60 de.)prior serving
• Don’t store food too long even in refrigerator
• Don’t thaw frozen food at room temperature
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
• Don’t use food beyond expiry date