Causes of food poising
Non-toxin medicated
Salmonella species
Domestic fowl is the common source of infection, which may be contracted from inadequately defrosted and undercooked or raw eggs.
Bacillius cereus
The infection is a hazard of eating rice which has been cooked and reheated and then consumed at a later date.
Listeria monocytogenesis (causing meningitis) is an environmental bacterium which can contaminate food, including poultry and cheese.
Viruses
Certain viruses, such as coronaviruses and rotaviruses commonly cause outbreaks of food poisoning, especially inistitution an and catering establishments
Toxin-mediated
Such poisoning is most commonly caused by the enterotoxin of S. aureus, frequently from a food handler with a septic lesion in on the hand.
Strains of clostridia, many of them relatively resistant to heat, can also contaminate certain foods-particularly meat.

Initial Clinical Features
Actiology Incubation Symptoms
Chemical poison, 30 minutes Vomiting
Staphylococcal or clostridiumoxin 2-6 hours Vomiting initially-may be diarrohea or abdominal pain
Salmonella infection 12-48 hours -
Haemorrhagic colitis 12-48 hours Bloody diarrhea predominates-may be abdominal pain

Investigations
A specimen of patient's stool or vomit together with the suspected food, if available, should be sent for culture. In more severe cases blood should be sent for culture.

Prevention
A reduction in the high incidence of food poisoning can best be achieved by improving the standards of personal hygiene, es especially in those handling food, and be stressing the importance of handwashing after using the lavatory. Low temperature storage is required for food which has to be kept for some hours or days before being consumed. It is essential to keep frozen poultry at room temperature for at least 12 hours before cooking.

Dr. (Miss) K Sarkar