2.5.3. HHP samples and unpressurized control samples
The surviving Listeria and yeast cells after each CCD treatment
were estimated in both the HHP samples and unpressurized control
samples by plating decimally diluted samples on selective and nonselective
media, as described in previous section.
When a detection limit of 2 Log cfu/mL was necessary, 100 mL
of neutralized sample was used by plating 10-mL aliquots in Petri
dishes (150 mm diameter, 70 mL medium/dish) and incubating
them in the appropriate conditions.
Moreover, using the Listeria model (developed by non-selective
counts), the sub-lethal damage of L. monocytogenes cells was
determined by treating a new series of HHP samples under the
conditions where the model calculates an adequate number of
survivor cells (intact þ injured) for its quantification (Table 1).