1. Introduction
Vacuum cooling is one of the most enhanced food
refrigeration processes that meet the requirements for
cooling rate of ready meals and their components. McDonald
and Sun (2000) recently provided a review of the
utilisation of this process in the food processing. One
of the vacuum cooling advantages is that the heat is
removed from food volume due to the evaporation of
water vapour from the food piece pores (Sun, 1999).
Some recent results on vacuum cooling modelling were
summarised by Houska, Bartos, Hoffman, and Sestak
(1999). It was found that the process can accurately be
simulated and its temperature history predicted provided
this reliable data for the product of mass transfer
coefficient and mass transfer surface are known.
Quick cooling is very important for cooked products
and semiproducts destined for preparing chilled or frozen
ready meals. It is essential, for these food materials,
to disable the potential growth of spores of sporeforming
pathogenic micro-organisms germinated after
gentle cooking. If the products are slowly cooled down, there is a great risk for microbial growth especially in
the range between 30C and 40C.