A genus of Gram negative, carbohydrate fermenting, non-spore forming bacteria of faecal origin. They can survive and may grow well in factory environments. The majority of strains are regarded as potentially pathogenic to humans. They cause an infective type of food poisoning, i. E. They multiply in the body. Consequently, only a small numbers of cells need to be present in the contaminated food. Salmonellosis is the illness caused by Salmonella bacteria. The illness is typical of a gastrointestinal infection - onset 12-36 hours after consumption of the food, with symptoms of diarrhoea, abdominal pain, fever, nausea, vomiting. The organisms are not indigenous to the aquatic environment, but can be found there following contamination with animal, including human, faeces.