The most common cause of food poisoning is bacteria. These bacteria cause symptoms such as vomiting, stomach cramps, headache, diarrhoea, fever or a combination of the above. Some food poisoning bacteria can cause death. Under the right environmental conditions, that is, warmth, food, moisture and time, bacteria can multiply through mitosis where one can split into two in every 10-20 minutes. Bacteria grow at temperatures between 5 and 63 OC and thrives at temperatures of about 37°C. Dried foods have a longer shelf life because bacteria needs moisture to grow. High levels of sugar or salt and acid is unconducive for the growth of bacteria. Bacteria also prefers foods that are high in protein and moisture. These high risk foods include meat, poultry, eggs and fish.
There are various types of food poisoning bacteria with each having own food sources. Salmonella is found in many types of raw meat, Listeria is found in raw poultry and other meats, Escherichia coli is found in raw meat, Clostridium perfringens is found in raw meat, vegetables, herbs and spices, while staphylococcus aureus is obtained from food handlers. (Ridgewell, 2001).
In the early 1980s, the number of recorded human cases of Salmonella enterica rose to over 10,000 cases in the UK, then increased for 20 years in England and Wales to a peak of 33,000 cases in 1997 (Cogan & Humprey, 2003). From 1998, the number has been decreasing till date. However, according to (Public Health England, 2014) there was an outbreak of Salmonella Enteritidis that caused three deaths and an outbreak of 247 cases from 158 on 15th of August 2014. There were 99 cases in Hampshire, 39 in Cheshire, 30 in London and 54 in the West Midlands. Salmonella Enteritidis is a bacterium that causes gastrointestinal illness and is often associated with poultry and eggs.
Salmonella belongs to the Enterobacteriaceae and are facultative anaerobic Gram-negative bacilli. Salmonella has an incubation