 Most strains of Escherichia coli bacteria are harmless and found in the intestines of warm blooded animals.  We need E. coli to breakdown cellulose and assist in the absorption of vitamin K, the vitamin that helps blood clotting.  However there is one type called E. coli 0157:H7, which was first discovered in 1982, that can cause illness.  The number following this bacteria’s name is referring to chemical compounds found on its surface.

 E. coli 0157:H7 can be found in the intestines of healthy cattle, which can contaminate meat during slaughter.  These organisms can also be thoroughly mixed into beef when it is ground. Bacteria may in addition contaminate the cow’s udders or milking equipment, which may then cause the bacteria to get into raw milk.  Eating the infected meat, that has not been cooked sufficiently to kill the E. coli can cause illness. Contaminated meat looks and smells normal.  It is also possible to become infected by eating sprouts, lettuce salami, unpasteurized fruit juice, and swimming in or drinking sewage contaminated water.  If personal hygiene is not adequate in an infected person, the bacteria contained in diarrhoeal stools can be passed to other people.

Severe bloody diarrhoea Abdominal cramps Nausea And occasionally non-bloody diarrhoea or no symptoms. The infection can additionally, particularly in young children and old people, cause a disease called hemolytic uremic syndrome. This destroys red blood cells and causes the kidney to fail. This affects 2- 7% of people with E. coli. It is diagnosed by identifying the bacterium in the stool.

 It is estimated that it takes as few as 10 organisms to infect a person with E. coli.  Once E. coli 0157:H7 get into the small intestine it destroys the microvilli and becomes firmly attached through a pedestal made of actin and actin binding proteins.  Then when inside the cell shiga toxins are released and taken up in coated pits in the epithelial cells, which then transports them to the golgi.  The toxins then travel from the golgi to the endoplasmic recticulum, where they destroy ribosomes, which results in the death of the cell.  This happens through out the gut lining. pedestal

 Salmonella is another type of food poisoning. It has been known to cause illness for over 100 years.  There are many types of Salmonella, but Salmonella sereptype Typhimurium and Salmonella serotype Enteritidis are the most common.  Salmonella is a rod-shaped, motile bacterium especially found in poultry.  Salmonella is found in the gut of many farm animals, especially those reared intensively with highly concentrated feeds.  The majority of chickens in deep litter houses have Salmonella in their gut.

 One of the main causes of Salmonella food poisoning is eating contaminated raw or inadequately cooked eggs or products made of raw eggs, such as homemade mayonnaise.  Newly laid eggs can also be contaminated with poultry faeces, which contains salmonella bacteria.  A more serious type of Salmonella called Salmonella typhi can produce typhoid or typhoid-like fever in humans.  Contaminated food is usually from animal origin but all foods, including vegetables can become infected by, for example insufficient washing of the hands after handling raw contaminated meat.  It is estimated that approximately 600 people die each year with severe salmonella.

 Abdominal cramps  Nausea  Vomiting  Diarrhoea  Chills  Headache  Fatigue  Fever.  Salmonella is diagnosed by identifying the bacteria in the stools of an infected person.

 Depending on the age and health of the host it can take only cells to start an infection.  The onset time for the disease is 6-48 hours and it can last 5-7 days.  Salmonella invasion triggers actin polymerisation and depolymerisation in the epithelial cell (this is sometimes called ‘membrane ruffling’) by the bacteria releasing a toxin.  This causes the epithelial cell to form pseudopods that engulf the Salmonella and place it in an endocytic vacuole.  The Salmonella replicate within the endocytic vacuole, killing the host cell and causing a inflammatory response.  The bacteria are then released from the cell to infect other cells.

 Due to the damage of the cells in the intestine walls caused by both bacteria, absorption can be affected causing diarrhoea.  The body also increases fluids to get rid of the infection also resulting in diarrhoea.  Diarrhoea can be fatal in malnourished children and the elderly due to the amount of fluid and electrolytes lost from the body.  if fluid loss becomes to severe an oral rehydration drink can be given to replace salts and sugars that have been lost.  There is usually no need for antibiotics to treat food poisoning unless it spreads from the intestine.  The main treatment is care of the patient.  Most people recover without intervention within 5-7 days.  The same antibiotic cannot be used to treat food poisoning each time because the bacteria are continually changing.

 Cook all meat thoroughly to kill all the bacteria.  Wash hands, kitchen work surfaces and utensils with soap and hot water immediately after they have been in contact with raw meat or poultry.  Wash all vegetables before preparation.  Only drink pasteurised milk and juice.  Make sure drinking water has been treated with chlorine, and be careful not to swallow lake or pool water while swimming.