Xeromyces

Xeromyces is a genus noted for its extreme xerophilic nature, capable of growing at water activities (aw) lower than almost any other known organism (down to ~0.61 aw). It is a monotypic genus (containing only X. bisporus) that poses a spoilage risk to low-moisture foods that are typically considered shelf-stable. Taxonomically, it is a key member of the Aspergillaceae, forming a distinct lineage related to Monascus.