They are refrigeration or freezing equipment specially designed to reduce the temperature of a food at the highest possible speed.
In vacuum cooking one of the key moments, if cooked food is not going to consume immediately, is the conservation of it. The temperatures at which it is cooked, normally between 60 and 80 degrees, are a perfect breeding ground for all types of microorganisms that could seriously affect our health. Therefore it is essential to reduce these temperatures at the highest possible speed. This prevents these microorganisms from proliferating and makes it a totally reliable conservation method.
A home mode is done by submerging the bag in which vacuum cooking has been done in ice water.
The method used in a restaurant is by means of a blast chiller that can take the food from a cooking temperature of 80 degrees to a storage temperature of 3 or 4 degrees in a short space of time.