Classification Of Food Poisoning

I. Based on symptoms and duration of onset:
a. Nausea and vomiting within six hours (Staphylococcus aureus, Bacillus cereus)
b. Abdominal cramps and diarrhoea within 8-16 hours (Clostridium perfringens, Bacillus cereus)
c. Fever, abdominal cramps and diarrhoea within 16-48 hours (Salmonella, Shigella, Vibrio
parahemolyticus, Enteroinvasive E.coli, Campylobacter jejuni)
d. Abdominal cramps and watery diarrhoea within 16-72 hours (Enterotoxigenic E.coli, Vibrio cholerae
O1, O139, Vibrio parahemolyticus, NAG vibrios, Norwalk virus)
e. Fever and abdominal cramps within 16-48 hours (Yersinia enterocolitica)
f. Bloody diarrhoea without fever within 72-120 hours (Enterohemorrhagic E.coli O157:H7)
g. Nausea, vomiting, diarrhoea and paralysis within 18-36 hours (Clostridium botulinum)
II. Based on pathogenesis
a. Food intoxications resulting from the ingestion of preformed bacterial toxins. (Staphylococcus
aureus, Bacillus cereus, Clostridium botulinum, Clostridium perfringens)
b. Food intoxications caused by noninvasive bacteria that secrete toxins while adhering to the
intestinal wall (Enterotoxigenic E.coli, Vibrio cholerae, Campylobacter jejuni)
c. Food intoxications that follow an intracellular invasion of the intestinal epithelial cells. (Shigella,
d. Diseases caused by bacteria that enter the blood stream via the intestinal tract. (Salmonella typhi,
Listeria monocytogenes)

Bacterial Etiology Of Food Poisoning:
Food infections by bacteria can be divided into two types:
1. those in which the food does not ordinarily support the growth of pathogens but merely carries them. E.g.
Salmonella, Shigella, Vibrio etc.

2. those in which the food can serve as a culture medium for growth of pathogens to numbers that can infect
the person.
Food borne infections by bacteria can also be classified as toxicosis and food-infections. In toxicosis, the toxins are
released by bacteria such as Clostridia, Bacillus and Staphylococcus. In food-infections, the bacteria are ingested,
which later initiate the infection