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
- Bacteria
Bacillus cereus
Staphylococcus aureus
Salmonella group (except S. typhi)
Shigella
Vibrio
Escherichia coli
Campylobacter
Yersinia enterocolitis
Clostridium - Viruses
Rotavirus
Adenovirus
Parvovirus - Protozoa
Giardia lamblia - Fungi
Aspergillus flavus
Fusarium roseum
B. Nonmicrobial Contamination - Vegetable origin
Lathyrus sativus
Mushrooms
Argemone Mexicana - Animal sources
Poisonous fish like shell fish, scombroid fish etc.
Mussel - 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. - 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. - 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. - 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. - 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. - 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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