Food Poisoning of Bangladesh

Food poisoning is an acute gastro-enteritis caused by ingestion of food or drink contaminated with either living bacteria or their toxins or inorganic chemical substances and poisons derived from plants and animals.

Food poisoning is characterized by

a. History of ingestion of common food.

b. Attack of many persons at the same time

c. Similarity of signs and symptoms in the majority of cases.

food poisoning

Types of food poisoning

food poisoning are of two types

1. Non-bacterial

Caused by chemicals such as arsenic, certain plants and sea foods.

In recent times by pesticides, mercury, cadmium, fertilizers.

2. Bacterial

(a) Salmonella food poisoning (b) Staphylococcal (c) Botulism (d) Cl. perfringes (e) cereus food poisoning.

Salmonella food poisoning

Salmonella food poisoning

An extremely common form of food poisoning.

Five reasons for increase in recent years.

1. An increase in communal feeding

2. Increase in international trade in human food.

3. A higher incidence of salmonellosis in farm animals

4. Widespread use of house-hold detergents interfering with sewage treatment

5. Wide distribution of “prepared food”.

(a) Agent

Most common species causing outbreak are S. typhimurium, S. cholera and S. enteritidis.

(b) Source

Salmonellosis is primarily a disease of animals.

  • Man gets infection from farm animals and poultry through contaminated meat, milk, and milk products, sausages, custards, egg and egg products.
  • Rats and mice contaminate foods by their feces.
  • Temporary human carriers cause spread of the disease

(c) Incubation period:

12 to 24 hours commonly

(d) Mechanism of food poisoning

  • The causative organisms, on ingestion, multiply in the intestine and give rise to acute enteritis and colitis.
  • The onset is sudden with chills, fever, nausea,vomiting and a profuse watery diarrhea which lasts 2-3 days.
  • Mortality is about 1 per cent.
  • Carrier state last for several weeks.

Styphylococcal food poisoning

Styphylococcal food poisoning

(a) Agent

Enterotoxins of certain strains of staphylococcus aureus.

Toxins can be formed at temp. 35 to 37 deg.c.

(b) Source

Staphylococci are found in the skin and in the nose and throat of man and animals.

Cows suffering from mastitis cause outbreak of food poisoning involving milk and milk products.

The foods involved are salads, custards, milk and milk products which get contaminated by staphylococci.

(c) Incubation period: 1-6 hours.

(d) Mechanism of food poisoning

  • Food poisoning results from ingestion of toxins preformed in the food in which bacteria have grown.
  • Since the toxins are heat resistant, so can remain in food after the organisms have died.
  • The toxins act directly on the intestine and CNS.
  • The illness becomes manifest by the sudden onset of vomiting, abdominal cramps and diarrhea.
  • In severe cases, blood and mucus may appear.
  • It rarely cause fever.
  • Death is uncommon.



Most serious but rare.

It kills two-thirds of its victims.

(a) Agent: Exotoxin of Clostridium botulinum.

(b) Source

The organism is widely distributed in soil, dust and the intestinal tract of animals and enters food as spores.

The food most frequently responsible for botulism are home preserved foods such as home-canned vegetables, smoked or pickled fish, home-made cheese and similar low acid foods.

Botulism derives from Latin word botulus means sausage.

(c) Incubation period: 12 to 36 hours.

(d) Mechanism of food poisoning

  • The toxin is preformed in food under suitable anaerobic condition.
  • It acts on the parasympathetic nervous system.
  • Botulism differs from other forms of food poisoning in that the GIT symptoms are slight.
  • The prominent symptoms are dysphagia, diplopia, ptosis, dysarthria, blurring of vision, muscle weakness and even quadriplegia.
  • Fever is generally absent, and consciousness is retained.
  • The condition is frequently fatal.
  • Death occurring 4-8 days later due to respiratory or cardiac failure.
  • Botulism in infants called “infant botulism”

Prevention of botulism

The toxin is heat labile, so heating the food up to 100 deg. C. for few minutes will make the food safe for consumption.

Antitoxin is used as prophylactic.

All cases should be given antitoxins as part of treatment.

Dose: 50,000 – 100,000 units I.V.

Guanidine hydrochloride, 15 to 40 mg/kg body wt given orally causes reverse of neuromuscular block of botulism.

Good medical and nursing care is necessary.

Active immunization botulinum toxoid is available to prevent botulism.

Cl. Perfringes food poisoning

Perfringes food poisoning

(a) Agent: Cl. Perfringes (welchii)

(b) Source :

  • Found in feces of humans and animals, and in soil, water and air.
  • Outbreak associated with ingestion of meat, meat dishes and poultry.
  • Foods usually cooked 24 hours or more before consumption.

(c) Incubation period: 6 to 24 hours, peak 10 to 14 hours.

(d) Mechanism of food poisoning

  • The spores are able to survive cooking.
  • Improper cooling of food favors the spores to germinate.
  • The organisms multiply and produce toxins like alpha, theta toxins etc.

(e) Clinical symptoms

  • Most common symptoms are diarrhea, abdominal cramps and little or no fever, occurring 8 to 24 hours after consumption of food.
  • Nausea and vomiting are rare.
  • Illness is of short duration,usually 1 day or less.
  • Recovery is rapid, no deaths have been reported.

Cereus food poisoning

food poisoning

(a) Agent:

Bacillus cereus is an aerobic, spore-bearing , motile, gram positive rod.

It is found in soil, and in raw, dried and processed foods.

The spores can survive cooking and germinate and multiply rapidly.

B. Cereus produces two types of enterotoxins causing two distinct forms of food poisoning .

1. Emetic form: short duration, upper GIT symptoms develop.

2. Diarrheal form: longer incubation period, lower GIT symptoms.

Investigation of food poisoning

a. Secure complete list of people involved and their history: Interview the people with questionnaire.

b. Laboratory investigation to detect bacteria.

c. Animal experiments

d. Blood for antibodies

e. Environmental studies

f. Data analysis.

Prevention and control of Food Poisoning

a. Food sanitation

  • Meat inspection
  • Personal hygiene
  • Food handlers
  • Food handling techniques
  • Sanitary improvements
  • Health education

(b) Refrigeration

Food to be kept in correct temp.

Never left in warm pantries.

Cook and eat the same day.

(c) Food surveillance

Regular food surveillance should be carried out to ensure food safety.

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