4. Conclusions
Limited to the considered species, the microbial cell inactivation
predicted in this study for some pressure and temperature combinations
is in compliance with the FDA requirement of a 5 Log
reduction of microorganisms in fruit juices and beverages (USFDA,
2004). The appropriate temperature selection in the pressure
treatment of smoothies permits cold pasteurization to be obtained
at pressure levels below 300 MPa, thus enabling HHP plant cost
reduction that is favourable for the industrialization of the process.
The conditions adopted in the present research for the recovery of
L. monocytogenes injured cells confirmed their effectiveness,
allowing the sub-lethal injury evolution in the surviving population
to be followed as the severity of the treatment increases. Additionally,
fluorescent cell staining methods provide additive information
on the injured cell physiology.