There are around two thousand species of Salmonella, with about two hundred of them being specifically pathogenic to humans.
The following is from The Bug Bible - http://www.safefood.net.au/AudienceHierarchy/TheBugBible/Default.htm
Salmonella was first isolated by Salmon and Smith in 1885 from swine affected with hog cholera. Since then many different serotypes of Salmonella have been isolated from a variety of sources. All Salmonella serotypes are considered potential pathogens in animal species and man.
The primary source of salmonellae is the intestinal tract of a wide variety of animals including man. These include pets, birds and wild animals, including both warm and cold blooded animals.
Salmonellosis is a communicable disease readily transmitted from animals to man either directly or through contaminated products of animal or plant origin, however, transmission from animal sources is more likely.
The number of cells required to produce illness varies with the serotype. Generally relatively few Salmonella cells are needed therefore, growth in the food is not a prerequisite for a food to cause illness.
Salmonella can survive well in the environment and can be widely disseminated. Cross-contamination from raw to cooked foods or contaminated raw foods are the primary causes identified in the investigation of outbreaks.
In the home the following practices are critical control steps in preventing or minimising the risk of Salmonellosis.
• Obtain food from safe sources
• Store perishable foods either chilled or frozen.
• Protect shelf stable food from moisture.
• Wash vegetables and fruit well.
• Cook foods to at least an internal temperature of 66ºC.
• If cooked food is not eaten immediately cool rapidly to 5ºC.
• Prevent cross-contamination from raw to cooked foods.
• Do not store reconstituted foods like re-hydrated dried milk in the temperature danger zone.
• Ensure that cleaning equipment like sponges and dishcloths are disinfected.
Wipe up meat juices with disposable paper towel.