The decontamination of surfaces using UV-based methods is an important and widespread option, particularly in the food industry. Microbiological validation with suitable test microorganisms are required to quantify the disinfection efficiency of such methods. The widely used mould strains Aspergillus brasiliensis and Aspergillus niger were classified as “S2” germs in Germany some time ago. As a result, these strains may only be used in authorised laboratories and are not allowed to be used at the site of machine manufacturers or in food facilities. It is to be expected that they may also be categorised “S2” in other countries. Furthermore, the recommendations of the VDMA (Machinery and Equipment Manufacturers Association) regarding the validation of UV-based sterilisation processes are used throughout Europe. The Aspergillus strains were also named as test germs in these recommendations.  

The identification of suitable surrogates for Aspergillus species was the aim of a research project at the Fraunhofer Institute IVV (Freising, Germany). Two suitable replacement strains for efficacy tests of xenon flash light and UV medium and low pressure lamps were tested in extensive studies and recommended for practical use. These strains have now also been included in the VDMA recommendations and replace Aspergillus niger resp. Aspergillus brasiliensis.