PROCESS DESCRIPTION

Manufacturers of starter cultures for yoghurts, cheese, etc. freeze the culture material in blocks and then dry it in freeze dryers. Sometimes the frozen blocks are also processed to granules to shorten the drying time. However, the survival rates of the cultures are not optimal with this method.   

An alternative is the technique of pelletizing. Here liquid or paste-like substances are fixed as pellets with the help of a cryogenic cooling medium. The process uses both the evaporation enthalpy of liquid nitrogen as well as the cooling energy of the cold gas.