All of the following organisms causes gastroenteritis in 6-7 hours, EXCEPT:

Food poisoning (gastroenteritis) can be caused by consuming food contaminated with bacterial or non bacterial organism or their toxins. The mode, time and severity of presentation varies with each organisms. The time of occurrence of symptoms following consumption of food depends on the incubation period of the organisms. The most common organisms and their incubation time are Staphylococcus aureus 1-8 hours Bacillus cereus 2-16 hours Clostridium perfringes 8-16 hours E.coli 24-72 hours Vibrio cholera 24-72 hours Salmonella 8-48 hours Shigella dysenteriae 24-72 hours Good to know: Preformed toxins in food are often associated with nausea and vomiting eg S,aureus, Bacillus cereus. Bacillus cereus with incubation period of 2-8 hrs causes mainly vomiting, and with incubation period of 8-16 hrs mainly vomiting. Ref: Jawetz, 'Medical microbiology', 23rd Edition, Page746.