damaged. Such damage can result from any exposure to adverse condi-
tions that might occur during food processing, such as chilling, freezing,
or drying, and increases the cell’s sensitivity to selective agents used in
media in subsequent stages of the isolation procedure. Failure to include
a resuscitation step could therefore result in the non-detection of cells
that might recover and cause infection if the food is mishandled.
The selective enrichment stage is intended to increase the proportion
of salmonella cells in the total microflora by allowing them to proliferate
Figure 7.7 Traditional cultural protocol for isolation ofSalmonellafrom food
242 Bacterial Agents of Foodborne Illness