A review article on food poisoning

INTRODUCTION
Food poisoning means illness resulting from ingestion of
food with microbial or non-microbial contamination.[1]
The condition is characterized by (a) history of ingestion
of a common food (b) attack of many persons at the same
time, and (c) similarity of signs and symptoms in the
majority of cases.[2] The World Health Organization
estimates that there are more than 1000 million cases of
acute diarrhea annually in developing countries, with 3-4
million deaths.[3] According to the Food Standards
Agency (FSA) there are nearly 900000 cases of food
poisoning each year. Our lifestyles have changed over
the last few years which include an increasing reliance
on ready prepared meals, eating out rather than cooking
and taking more holidays abroad. We all lead busy lives
and as a result of that tend to spend less time preparing
and cooking food. People often cook several meals in
advance and freeze them for a long period of time or buy
convenience food which only has to be put in a
morigin
ve oven. This is the reason for increasing food
poisoning cases in present scenario. Knowing where
your food is sourced from and the standards of care and
safety that have been applied may help to reduce the
incidences of food poisoning.
[4]
Causes Of Food Poisoning.
[1]
A. Microbial Contamination

1. Bacteria
    Bacillus cereus
    Staphylococcus aureus
    Salmonella group (except S. typhi)
    Shigella
    Vibrio
    Escherichia coli
    Campylobacter
    Yersinia enterocolitis
    Clostridium
2. Viruses
    Rotavirus
    Adenovirus
    Parvovirus
3. Protozoa
    Giardia lamblia
4. Fungi
    Aspergillus flavus
    Fusarium roseum
   B. Nonmicrobial Contamination
5. Vegetable origin
    Lathyrus sativus
    Mushrooms
    Argemone Mexicana
6. Animal sources
    Poisonous fish like shell fish, scombroid fish etc.
    Mussel
7. Chemicals
    Flavoring agents
    Coloring agents
    Preservatives
   Classification of Food Poisoning.
   [5,6,7]
   Factors Leading To Food Poisoning[8]
   Enteric pathogens have developed a variety of tactics to
   overcome host defenses. Understanding the virulence
   factors employed by these organisms is important in the
   diagnosis and treatment of clinical disease.
8. Inoculum size: The number of microorganisms that
   must be ingested to cause disease varies
   considerably from species to species. For Shigella,
   enterohemorrhagic Escherichia coli, Giardia
   lamblia, or Entamoeba, as few as 10-100 bacteria or
   cysts can produce infection, while 105
   -108 Vibrio
   cholerae organisms must be ingested orally to cause
   disease.
9. Adherence: Many organisms must adhere to the
   gastrointestinal mucosa as an initial step in the
   pathogenic process; thus, organisms that can
   compete with the normal bowel flora and colonize
   the mucosa have an important advantage in causing
   disease.
10. Toxin Production: The production of one or more
    exotoxins is important in the pathogenesis of
    numerous enteric organisms. Such toxin include
    enterotoxins, which cause watery diarrhea by acting
    directly on secretory mechanisms in the intestinal
    mucosa; cytotoxins, which cause destruction of
    mucosal cells and associated inflammatory diarrhea;
    and neurotoxins, which act directly on the central or
    peripheral nervous system.
11. Invasion: Dysentery may result not only from the
    production of cytotoxins but also from bacterial
    invasion and destruction of intestinal mucosal cell.
    Infections due to Shigella and enteroinvasive E. coli
    are characterized by the organisms’ invasion of
    mucosal epithelial cells, intraepithelial
    multiplication, and subsequent spread to adjacent
    cells.
12. Host Defenses: Normal host can protect itself
    against disease. Food poisoning depends upon host
    defense mechanisms e.g. Normal flora, Gastric acid,
    Intestinal motility, Immunity and Genetic
    determinants.
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