Bacterium
Bacillus cereus
Reheated-rice food poisoning rod
buh-SIL-us SEER-ee-us
High-yield clue
Reheated rice held warm is the classic clue: the heat-stable emetic toxin cereulide causes vomiting, while a separate heat-labile enterotoxin causes watery diarrhea.
Overview
A spore-forming Gram-positive soil rod used in coursework to connect two distinct foodborne toxin syndromes with the same organism. Its heat-stable emetic toxin makes it a classic teaching example of preformed-toxin food poisoning.
Classification
- Gram-positive
- Rod (bacillus)
- Spore-forming
- Facultative/aerobic
- Beta-hemolytic
Lab & identification clues
- Large box-car Gram-positive rods
- Endospore-forming
- Beta-hemolytic colony vocabulary
- Motile teaching distinction
Associations
- Reheated fried rice food poisoning
- Emetic (cereulide) vs diarrheal enterotoxin syndromes
- Ocular/keratitis study association
Commonly confused with
- Bacillus anthracis
- Staphylococcus aureus preformed-toxin poisoning
Your notes
Original student-study summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment, dosing, or specimen-handling guidance.