Moulds in containers with biological wastes.

The collection of biological wastes in separate bio-containers can lead to a favoured development of thermophilic and thermotolerant moulds, especially of mucoraceous species and aspergilli, among which the human pathogen A. fumigatus is especially frequent. The abundantly produced spores are released into the air and can evoke severe infections in persons with immune-deficiencies. In two series of experiments it was demonstrated that the following procedures can reduce the number of spores in the air in the bio-containers above the biological wastes: (1) wrapping the wastes in portions in newsprint: the number of colony-forming units (CFU) decreases for about 50-70%; (2) cleaning of the container after each emptying with diluted vinegar: the number of CFU is reduced for up to 80%; (3) placing the container at shady sites: the temperature of the air inside the bio-containers at shady sites is approximately 5-8 degrees C lower than at sunny places with the consequence that the number of CFU in the air above the biological wastes is decreased. Based on these results principles for the handling of biological wastes are set up.