The growth phase during which Staphylococcus aureus produces enterotoxin in contaminated food?

• A. Stationary phase
• B. Lag phase
• C. Exponential phase
• D. Death phase

Answer: (A)

Staphylococcus aureus makes enterotoxins in contaminated food mainly when the bacterial population has grown to high density and nutrients start to run low, which is the stationary phase. At this stage, cells shift from rapid growth to survival mode, and regulatory systems activate toxin production. Because the toxins are preformed in the food during this growth, they can cause illness even after cooking since many enterotoxins are heat-stable. In the lag or exponential phases, growth is ongoing and toxin production is not yet at the levels seen in stationary phase, and in the death phase cells are declining.