Staphylococcus aureus, Bacillus cereus and Clostridium botulinum are bacteria with preformed toxins. They have a sho incubation period of 1-6hr and produce diarrhea. Strains of E coli known to cause diarrhea are enterotoxigenic, enteropathogenic, enteroinvasive, enterohemorrhagic and enteroaggregative. Enterohemorrhagic E coli is known to produce one or more Shiga toxins and contribute to the development of bloody diarrhea, HUS, TTP and microangiopathic hemolytic anemia. Patients develop symptoms after an incubation period of 3-5 days, when they sta to get watery diarrhea for 2-5 days which then progress to develop bloody diarrhea. Bacterial strain with moderate incubation period ( 8 to 16 hrs) Clostridium perfringens Bacterial strain with long incubation period(more than 16 hrs) Toxin producing organisms: Clostridium botulinum Enterotoxigenic E coli Enterohemorrhagic E coli Vibrio cholerae Invasive organisms: Salmonella Shigella Clostridium jejuni Yersinia enterocolitica and Yersinia pseudotuberculosis Vibrio parahaemolyticus Enteroinvasive E coli Vibrio vulnificus Ref: Trier J.S. (2012). Chapter 5. Acute Diarrheal Disorders. In R.S. Blumberg, R. Burakoff (Eds), CURRENT Diagnosis & Treatment: Gastroenterology, Hepatology, & Endoscopy, 2e. Ferri's Clinical Advisor 2012: 5 Books in 1, Expe Consult - Online and Print By Fred F. Ferri page 392.