Gastroenteritis

The facts:

• Gastroenteritis is caused by a variety of viral, bacterial, and parasitic pathogens.
• In the USA, incidence rates for diarrhoea are 1-2.5 episodes per child per year, which annually leads to approximately 38 million cases, 2-3.7 million physician visits, 320,000 hospitalizations, and 325-425 deaths.
• In the UK, at least 2 million people a year suffer from an attack of diarrhoea and/or vomiting due to food poisoning. Most do not consult their doctor and so the cause is not often found.
• Worldwide, there are more than 1 billion cases and at least 4 million deaths per year attributed to diarrheoa.
• Pathogenic food-borne microbes are isolated in only about 1 in 100,000 cases of gastroenteritis.
• Virus infections cause 30-40% of gastroenteritis cases in industrialized countries. Very few of the infectious agents responsible for these outbreaks are ever diagnosed.
• Estimated costs of food-borne diseases in the USA alone range from 4.8 to 23 billion US dollars per year.

(Some of) the organisms responsible:

Bacillus cereus     Gram-stained cells: 1 µm wide, 5-10 µm long, arranged singly or in short chains:

Escherichia coli

Gram-negative rods, ~1-2 µm wide, 3-30 µm long:

Salmonella typhimurium:

Phase contrast microscopy, cells ~1 µm wide, 2-6 µm long.

Staphylococcus

Gram-positive cells ~1 µm diameter, arranged like "bunches of grapes":

How to Prevent Food Poisoning: A Practical Guide to Safe Cooking, Eating, and Food Handling
by Elizabeth Scott, Paul Sockett.
Provides guidelines on how to prevent contamination in food prepared in the home, eat safely in restaurants, be sure the food you buy is safe, transport and store food, and properly prepare leftovers.
(Amazon.co.UK)

Microbiology
by L.M.Prescott et al.
A balanced, comprehensive introduction to all major areas of microbiology. The sixth edition has been updated extensively to reflect the latest discoveries in the field.
(Amazon.co.UK)