Phage contaminations
Bacteriophages cause the most devastating contaminations usually resulting in destruction of bacterial culture with subsequent contamination of facility due to sampling or leakage caused by equipment failure. In this type of contamination, equipment failure is likely to occur in some equipment set-ups due to extensive foaming and possible clotting of exhaust filter with subsequent pressure build-up.
Bacterial contaminations
This is the most common type of contaminant in bacterial cultures. Depending on the type of bacterium contaminating the process, the effects brought about are different. In all cases, one may expect reduced yield of product, and possible contamination by metabolites of contaminating bacteria. In some cases toxins may be produced by contaminants. The probability of occurrence of a particular type of contaminations caused by bacteria may differ, depending on the process itself and the organism used in the process. One of the most frequently occurring contaminants are lactic acid bacteria and sporulating bacteria. Clean-up and re-occurrence prevention of especially the latter presents a considerable challenge.
Fungal contaminations
Due to relatively low growth rate of fungi when compared to bacteria, this problem may occur mainly in processes based on continuous bacterial fermentation. However, once occurred, fungal contamination causes very cumbersome and often expensive restart of whole production line.
