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Food poisoningA public health perspective
Dr. Rizwan S AAssistant ProfessorVMCHRI, Madurai
07.09.2015
Objectives of this lecture
• At the end of this lecture you should be able to– Define food poisoning– State types and
differentiate causes of food poisoning
– Describe the public health importance and prevention aspects of food poisoning
Importance of food safety
• Nearly 200 diseases are caused by unsafe food
• Two million deaths occur every year from contaminated food or drinking water
• Unsafe food creates a vicious cycle of disease and malnutrition, particularly affecting infants, young children, elderly and the sick
Definition
• An acute gastro-enteritis
• Caused by ingestion of food or drink
• Contaminated with bacteria or toxins or chemicals or poisons
Types and Causes
• Bacterial– Toxin type
• Staphylococcus • Streptococcus• Cl. Botulinum
– Infection type• Salmonella
• Non-bacterial– Virus
• Enteroviruses– Parasite
• Giardia, entamoeba– Protozoa
• Nematode• Flatworm• tapeworm
– Chemical• As, Hg, Cd, Cu
Types of bacterial food poisoning
Details of some important causes
• Salmonella• Staphylococcus• Cl. botulinum• Cl. perfringens• B. cereus
• S. typhimurium, S. enteritidis
• Farm animals, poultry• Incubation: 12–24 hr• Mech: infection• Fever, vomiting, watery
diarrhea lasting for 2-3 days
Details of some important causes
• Salmonella• Staphylococcus• Cl. botulinum• Cl. perfringens• B. cereus
• Enterotoxins of Staphylococcus aureus
• Salads, custards, milk products
• Incubation: 1–6 hr• Mech: Preformed toxin• Vomiting, abdominal
cramps, diarrhea
Details of some important causes
• Salmonella• Staphylococcus• Cl. botulinum• Cl. perfringens• B. cereus
• Exotoxin of Clostridium botulinum type A, B or E
• Fish, cheese, canned vegetables
• Incubation: 12–36 hr• Toxin affects PS system• Dysphagia, diplopia,
dysarthria, muscle weakness, quadriplegia
Details of some important causes
• Salmonella• Staphylococcus• Cl. botulinum• Cl. perfringens• B. cereus
• Clostridium perfringens• Meat, poultry - cooked and
allowed to cool slowly at room temperature
• Incubation: 6-24 hr• Mech: spore germination• Diarrhoea, cramps, rapid
recovery in 1 day
Details of some important causes
• Salmonella• Staphylococcus• Cl. Botulinum• Cl. perfringens• B. cereus
• Bacillus cereus• Raw, dried & processed
foods• Incubation: 12-24 hr• Mech: spore germination• Emetic form: upper GI
symptoms (1-6 hr)• Diarrheal form: lower GI
symptoms (12-24 hr)
Review QVomiting occurs in group of children in the night, who had meal at noon. The causative agent for food poisoning is most likely to be:a. Salmonella b. Botulism c. Staphylococcus d. Viral gastroenteritis
True about staphylococcous food poisoning are all except: e. Due to enterotoxin f. IP below 6 hours g. Sudden onset h. Fever is common
Differential diagnosis of bacterial poisoning
How to investigate a food poisoning outbreak as a public health expert? Interview all people
Food eaten during previous
2 days
Place of consumption
Time of onset of symptoms
Order of onset of symptoms
Questionnaires given to
kitchen workers & dining
workers
Lab diagnosis
Stool, vomit or remnants of
food
Stool samples of kitchen
employees & food handlers
tested
Blood for antibodies
Environmental studies:
Inspection of kitchens
Findings of an investigation
Review Q
Food poisoning is caused by all except
a. Staphylococcus aureus b. Clostridium difficile c. Vibrio parahaemolyticusd. Bacillus cereus
Prevention and control
• Food sanitation• Refrigeration• Surveillance
1. Meat inspection2. Personal hygiene3. Healthy food handlers4. Food handling
technique5. Sanitary improvement6. Environ. hygiene7. Health education
Prevention and control
• Food sanitation• Refrigeration• Surveillance
• Food should be immediately & rapidly refrigerated if not eaten after cooking (<40 Celsius)
• “Cook and eat the same day”
Prevention and control
• Food sanitation• Refrigeration• Surveillance
• Food samples obtained from food establishments periodically and checked.
• Record of foodborne disease outbreaks
Review Q
What is correct temperature for refrigeration of food?
a. <5 degree Cb. 10-20 degree Cc. >60 degree Cd. 5-10 degree C
What are the 5 keys to safe food?
Take home messages
1. Food poisoning is a common outbreak2. It affects vulnerable people like children3. Most important causes are bacterial4. DD is possible by symptoms, food, IP5. All outbreaks sh be investigated
epidemiologically6. Food sanitation is main prevention method
THANK YOUEmail your queries to [email protected]