Pressure treatment at 500 and 600 MPa for 1 min significantly reduced
the TAC, LAB and Pseudomonas counts of lasagne ready meals.
During storage at both refrigeration and abuse temperature the
counts remained lower, significantly prolonging the shelf life of the
product compared to untreated controls.
HPP was able to control
the safety risks associated with L. monocytogenes, as treatmentwith
600 MPa resulted in a reduction below the detection limit for
L. monocytogenes immediately after treatment with the counts remaining
belowthe detection limit throughout storage 4 °C.
However,
pressure treatment at 600MPa followed by storage at 8 °C resulted in
the recovery of L. monocytogenes after 7 days of storage, highlighting
the importance of a good chill chain to maintain product safety.
HPP was also able to significantly reduce the counts of S. aureus and keep
them at low levels at both storage temperatures.
The organoleptic
characteristics of lasagne were not affected by the pressure treatment
and remained relatively stable during storage.
These results indicate
that HPP can be used as an additional post-packaging safety
step in the production of multicomponent ready meals by the food
industry.