Freshly harvested CCM always contains a certain amount of moulds, yeasts and bacteria. It is the challange to stabalise these micro-organisms, so that they don't increase. This depends on a correct storage method.
The natural preservation of CCM is carried out by lactic acid bacteria. If this process is carried out directly after the harvesting, then the probability that the micro-organisms develop is small. This is the optimal situation. However, the natural process is often influenced by factors such a high temperature and high humidity level. This creates an ideal environment for the development of moulds, yeasts and bacteria. They can then increase exponentially which has a negative effect on the quality of the CCM.