Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Maitz, S.
Analysis of Bacterial Communities during the Manufacture of Packaging Materials, in the Final Product and their Transfer to Contact Surfaces
Doktoratsstudium der Medizinischen Wissenschaft; Humanmedizin; [ Dissertation ] Medizinische Universität Graz; 2022. pp.
- Autor*innen der Med Uni Graz:
- Betreuer*innen:
- Kittinger Clemens
- Moissl-Eichinger Christine
- Altmetrics:
- Abstract:
- Introduction. Microbial growth and biofilm formation are common issues in production processes using water circulation systems, as it is the case in industrial manufactories. The entry of microorganisms can occur in several steps during production. In addition, microorganisms enter the production by used raw materials. As a result, microorganisms are introduced into the product. Moreover, the microbial transfer from packaging materials to a contact surface is not sufficiently researched. In fact, bacterial transfer from fiber-based materials has been studied from laboratory produced packaging products spiked with spores on agar surfaces at low levels (0.03–0.10%). In contrast, a transfer of 0.01–0.02% of the total microbial load of fiber-based materials to a contact agar was observed in one study for industrially produced packaging materials. Aim. On the one hand, this study focuses on increasing the knowledge of the microbial diversity in industrial machinery during a production cycle and identifying the common bacterial community in three machines. On the other hand, on the characterization of microorganisms on/in industrially produced packaging materials and on the establishment of an experimental laboratory setup to determine and quantify parameters influencing the microbial transport from surfaces and different layers of packaging materials to contact agar media. Materials and Methods. Next-Generation-Sequencing (NGS) methods were used to determine the microbial composition in biofilm, process water and packaging material from three production machines with different temperature profiles from three different time points. Moreover, simple models were established to determine the transfer of microorganisms form packaging materials via liquids and airflows to microbiological agar plates. The microbial transfer was investigated from the outer layers (front and back), the matrix (inner layers), specific sectors of one outer layer, incubation time, applied weight and bacterial load of the samples in more detail. Results. The NGS data analysis of all machines determined that mainly Gram-negative bacteria are occurring in the industrial microbiome of the machines. The temperature in each of the tested machines influenced the diversity of microorganisms in the machines tested. The top common microbial genera in all machine and sample types were Tepidimonas, Cloacibacterium, Bacillus and Pseudomonas. Transfer analysis revealed a significant difference between the outer layers and a time-dependent transfer to the media was indicated. In contrast, an independence of microbial transfer between inner and outer sectors, outer and inner layers and from applied weights were measured. Furthermore, with the tested samples, only a very low transfer via airflow was observed, compared to liquid.