FOOD BORNE DISEASES

1. FOOD BORNE DISEASES Dr Gaurij Hood

2. 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

3. 1.Introduction • Food borne diseases-(intoxications and infections) covers illnesses acquired through consumption of contaminated food-i.e food poisoning • Food bornedisease 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

4. 1.Introduction –Burden • Global burden-highmorbidity 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)

5. 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 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/s-vomitting,nausea,diarrhea,diplopia,weaakness,resp.failure,numbness,sensory/motor dysfunction Not communicable Factors-inadequate cooking,improper handling temperatures Food borne infections vs intoxication

6. 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.protozoa-cryptosporidium,cyclospora,entamoeba,giardia,t gondii • 4.trematodes,cestodes and nematodes

7. Food borne pathogens-toxins and chemicals • Toxins-marine biotoxins,tetrodotoxin(pufferfish),pyrrolizidine alka,mushroom toxins,shellfish toxins,mycotoxins,plant toxicants • Chemicals-pesticides(opp,sb),radionuclides,nitrites(food preservatives),toxic metals-cd,cu,hg,pb,sn,fluoride,MSG

8. 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

9. Some common bacterial food poisons

10. Some common bacterial food poisons

11. Some common bacterial food poisons

12. Early diagnosis and investigations • 1.Initial assessment of cases-Detailedclinical 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 clinicalexamination-vitals and degree of dehydration,systemic signs

13. Lab diagnosis • Main objectives- • a)To confirm clinical diagnosis by isolation of causative agent from proper samples,eg-stool,vomitus/gastricaspirate,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

14. 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 possiblehypothesesEpidemiological study to evaluate hypothesesAnalysis of data and interpretationReporting findings of outbreak investigation

15. 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

16. 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)

17. 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

18. Treatment • 1.Initialt/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

19. 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)

20. 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.

21. 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 cookedfood-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

22. 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

23. 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