EN Widerstandsfähigkeit gegenüber Mikroorganismen

Fungi and bacteria that colonize plastic surfaces can degrade the plastic or cause damage to the plastic components through the influence of their metabolic products. Such effects of microorganisms can be detected using the various methods (methods A to C) of DIN EN ISO 846.

In method A, the resistance of a plastic to fungi is tested. A spore suspension of 5 different fungi is dripped onto the material samples and incubated for 4 weeks. If the plastic contains components that can be utilized by the fungus, the material is degraded. In a similar, more advanced method, the fungistatic or fungicidal effect (methods B and B') can be determined. Here, the plastic is placed on a carbon-containing culture medium with fungal spores in order to be able to examine growth inhibition on or around the sample.

Method C is used to determine the resistance of a plastic to bacteria. The samples are embedded in a carbon-free nutrient agar with the bacterium Pseudomonas aeruginosa. Increased growth of the bacterium at the edge of the sample indicates utilization of the material and possible decomposition.