Ans: a (Salmonella typhimurium) Ref: Ananathanarayan,7th ed, p. 303Of the above given, S. typhimurium causes food poisoningSalmonella gastroenteritisS. typhimurium is the most common cause of food poisoning due to salmonella species.Incubation period--6-24 hrsFood poisoning is never caused by S. typhi. Source of transmission: poultry, meat, milk and milk products.C/F-nausea, vomiting, diarrhoea, abdominal cramps, fever.Blood culture is usually negativeNoteS. aureus is the most common cause of food poisoning in the westIP and clinical features of various bacteria causing food poisoiningIncubation period Organism responsible 1- hrs S. aureus-nausea, vomiting, diarrheaB. cereus-nausea, vomiting 8-16 hrs C. perfringes-abdominal cramps, diarrhoea (vomiting rare)B. cereus-abdominal cramps, diarrhoea, vomiting > 16 hrs Vibrio cholera-watery diarrhoeaETEC-watery diarrhoeaEHEC-bloody diarrhoeaSalmonella species-inflammatory diarrhoeaCamphylobacter jej uni-inflammatory diarrhoeaShigella species- dysentryV. parahaemolyticus-dysentry