Bottled mineral water is distributed globally through complex supply chains, making it available far beyond its bottling plants. In low-viscosity food matrices, invisible changes may occur due to shaking. The primary purpose of this research was to investigate the potential correlation between the intensity of mechanical agitation and the number of detectable microorganisms in bottled mineral water. The simulation of dynamic mechanical vibration was conducted using both time-accelerated and real-time tests. Freshly bottled natural mineral water and commercially available mineral water brands from different bottling locations and times were subjected to random vibration at three intensities as specified by the ASTM D-4169-16 standard, which simulates road transport on semi-trailer trucks. The study investigated the specific growth rate, the generation time, and the maximum cell numbers of microorganisms. The quantitative PCR (qPCR) technique was used to determine and compare the concentrations of microbes. Dynamic mechanical vibration affected the microbiome of mineral waters, influencing growth rates and generation times. In the case of waters from different bottling locations and times, the specific growth rate varied significantly for each water and for each intensity. This finding demonstrates that the microbiome composition of the water source and the interaction between microbes influence the response to mechanical impact. The time-accelerated test was shown to be suitable for analyzing the reaction of the microbiome of the tested matrix to the intensity and duration of vibration. The applied test protocol enabled the monitoring of changes in cell numbers by qPCR. All three intensities of the time-accelerated method were effective in testing the effects of real-time mechanical agitation on the microbiome.

The objective of this study was to find an efficient, rapid, simple, and cost-effective method of pretreating raw milk samples to produce PCR-ready DNA for subsequent microbial detection using the strains of eight bacterial species. A total of 17 in-house protocols and three commercial kits were evaluated in three steps from scientific, practical, and economic perspectives. The results showed that an in-house procedure involving Triton X-100-based pretreatment and an inhibitor removal resin was superior to all other methods tested in terms of DNA yield, sensitivity, ease of sample handling, time efficiency, and cost per sample. Overall, this simplified preanalytical protocol was shown to have a great potential for use in rapid detection of dairy-related bacterial species, thereby enabling early intervention in the food chain and thus reducing the risk of negative economic and health outcomes.

Systematic studies on 70 MACC isolates previously identified as ‘Chlamydomonas’, a unicellular flagellate, were carried out based on partial 18S rRNA. The aim of this study was to determine the phylogenetic affiliations of Chlamydomonas strains in the MACC collection. The study found that most of the strains were not Chlamydomonas. Nine clusters of phylogenetically similar taxa were identified. The previous determinations were completed with their new phylogenetic affiliations (partly due to changes in green algae classification). Molecular data revealed that 3 of the 70 strains are from Arenicolinia, 14 are members of the phylogroup Stephanosphaerinia, 11 are Oogamochlamydinia, 1 is Chloromonadinia, 19 are Reinhardtinia, 2 are Polytominia, 9 are Scenedesmaceae, 5 are Moewusinia, and 6 are Chlorella. Clades were established by 18S rRNA similarity and p-distances. This study reveals the need to revise established culture collections whose isolates are solely identified with morphology.

Study on 37 MACC isolates previously identified as “Anabaena,” a freshwater filamentous heterocytous taxon, were carried out using the 16S rRNA. The study found that most of the strains were misidentified at genus level. Three clusters of phylogenetically and morphologically similar taxa were identified. The previous determinations were amended with their new taxonomic classifications (partly due to changes in cyanobacterial classification). Some morphological structures could not be found in the cultures (e.g. akinetes). Molecular data revealed that 6 of the 37 strains are Desmonostoc, 8 are members of the genus Nostoc, 19 strains bear genetic resemblance to the genus Trichormus and 4 strains remain unresolved. Clades were established by 16S rRNA similarity and p-distances. The goal of this study was to amend the strain designations in this collection. This study reveals the necessity to revisit established culture collections that originally used only morphological classifications for species identification.