Principles of Food Sanitation

The Relationship of Microorganisms to Sanitation 29

Log number of microorganisms

Lag phase

Logarithmic

growth phase

Stationary

growth phase

Accelerated

death phase Reduced death phase

TIME

Figure 3–1Typical growth curve for bacteria.

a

b

Log number of microorganisms

Lag phase

Logarithmic

growth phase

TIME

Stationary

growth phase

Accelerated

death phase Reduced death phased

c

Figure 3–2The effect of initial contamination and lag phase on the growth curve of microorganisms: (a) high
initial contamination and poor temperature control (short lag phase), (b) low initial contamination and poor
temperature control (short lag phase), (c) low initial contamination and rigid temperature control (long lag
phase), and (d) typical growth curve.