The chamber filling factor (sample/chamber volume ratio) is
approximately 0.7, which represents the maximum limit achievable
in the batch processing mode of packaged foods (0.5e0.7). However,
either the filling factor or the geometry of the pressure vessel
may be critical to the pressure effects, particularly for sub-zero
treatments, as reviewed by Rastogi, Raghavarao,
Balasubramaniam, Niranjan, & Knorr (2007). Thus, preliminary
trials were carried out to evaluate the effects of different filling
factors (0.5 and 0.7). Comparison of the data (unpaired T-test)
showed that the two relative dimensions of the bag and cylinder
are not critical to the pressure induced effects on the microorganisms
used in this study (Zacconi & Scolari, submitted for
publication).