Salmonella

Salmonella demonstrates exponential growth at its extreme: under ideal conditions, populations can double every 20 minutes. This is among the fastest bacterial replication rates documented, enabling a single cell to become 16 million cells within 8 hours. The speed isn't accidental—Salmonella evolved to colonize host intestines rapidly before immune responses mobilize. But this explosive growth capacity creates survival challenges: the same rapid metabolism that enables quick doubling also depletes nutrients faster, triggering earlier entry into stationary phase. Salmonella's growth curve exemplifies Amara's Law: the lag phase (preparing metabolic machinery) is imperceptible, the exponential phase (20-minute doublings) feels unstoppable, and the stationary phase (nutrient depletion) arrives faster than exponential extrapolation predicts. The bacterium's pathogenicity emerges from this growth dynamic—rapid colonization overwhelms initial defenses, but also triggers strong immune responses that constrain long-term growth. In food safety, Salmonella's doubling rate determines critical thresholds: food held at room temperature for 4 hours provides 12 doubling periods, turning minimal contamination into infectious doses.