Fungal findings in natural mineral water systems: a monitoring- and health-oriented interpretive review

A horizontal schematic begins with a fungal finding in the source or water phase. It emphasizes that water-phase sampling alone may provide only a snapshot, may miss hidden surface or biofilm reservoirs, and may be misleading when release is intermittent. The interpretation becomes stronger when the finding is linked to system context, including the water phase, technological surfaces, biofilm and critical points. Three implications are shown: a fungal finding is first a system-hygiene signal; recurrent or site-specific findings may indicate persistence or a reservoir; and health relevance should be interpreted cautiously using taxonomic identity, recurrence and exposure context. The take-home message is that bulk-water results are most informative when combined with targeted surface or biofilm follow-up and confirmatory identification. Natural mineral waters are widely perceived as intrinsically clean and safe, yet microbiologically they are non-sterile ecosystem-based matrices shaped by source characteristics, bottling technology, storage conditions and overall system integrity. This interpretive review examines yeasts and filamentous fungi detected in natural mineral water and related bottled-water systems, with emphasis on commercial bottling quality control, system hygiene, monitoring design, persistence and cautious health interpretation. Because direct evidence from natural mineral water systems remains limited, selected studies of bottled water, drinking-water networks, biofilms and dispensers are used as supportive mechanistic context. Across the literature, isolated bulk-water results are usually less informative than recurrent, sampling-point-specific or surface-associated findings, which may indicate biofilm-linked reservoirs within the technological system. The practical response to a recurrent or site-specific finding is therefore paired water-and-surface sampling, taxonomic confirmation, a targeted hygiene investigation and verification of corrective measures. Environmental detection alone does not establish infection risk or mycotoxin exposure.