Penicillium nalgiovense

Penicillium nalgiovense. It is a filamentous fungus of significant industrial importance, particularly in the food sector for the fermentation and surface ripening of various meat products. First isolated from a cheese in Náchod, Czech Republic, this species is a key component in the production of traditional cured sausages and hams across Europe. Its safe use is supported by a long history of application and its classification as a GRAS (Generally Recognized as Safe) organism by regulatory bodies like the United States Food and Drug Administration.

Taxonomy and classification

The species was first described by Otto Laxa in 1932 after its isolation. It belongs to the extensive genus Penicillium, within the family Aspergillaceae, and is phylogenetically related to other food-grade molds such as Penicillium chrysogenum and Penicillium roqueforti. Taxonomic studies, including those utilizing DNA sequencing of loci like the Internal transcribed spacer (ITS) region, have confirmed its distinct species status. The Centraalbureau voor Schimmelcultures (CBS) and the International Mycological Association maintain important reference strains for this organism.

Description and morphology

Colonies of this fungus typically exhibit a velvety to floccose texture and display colors ranging from blue-green to grey-green, often with a white periphery. The reverse side of the colony is usually pale to yellowish. Microscopically, it produces characteristic brush-like conidiophores bearing chains of conidia. The conidiophores are terverticillate, a common structural feature in the genus, and the conidia themselves are smooth-walled and subglobose to ellipsoidal in shape. These morphological traits are consistent with those observed in other members of the Penicillium chrysogenum clade.

Habitat and ecology

Naturally, this fungus is a saprophyte commonly found in soil and decaying organic matter. It has been isolated from various environments, including forest floors, agricultural fields, and food production facilities. Its ecological role involves the decomposition of complex organic polymers, contributing to nutrient cycling. While it is ubiquitous, its presence is particularly noted in the environments of traditional Central European and Mediterranean dry-curing facilities, where it has become a resident microflora essential for the characteristic ripening process.

Industrial and culinary uses

This species is industrially cultivated as a starter culture for the surface inoculation of fermented meat products, most notably dry-cured sausages like salami and chorizo, and hams such as Prosciutto di Parma. The fungus creates a protective white coating that regulates moisture loss, prevents the growth of undesirable microbes, and contributes to flavor development through proteolytic and lipolytic enzyme activity. Its application is a hallmark of traditional European charcuterie, with companies like Rudolf Müller and Chr. Hansen being major commercial suppliers of fungal starter cultures containing this organism.

Safety and regulation

Due to its long history of safe use in food fermentation without reported adverse effects, it holds a Qualified Presumption of Safety (QPS) status from the European Food Safety Authority and is listed as a GRAS organism. Regulatory oversight ensures that production strains do not produce harmful mycotoxins, such as cyclopiazonic acid, which can be produced by some related Penicillium species. Routine screening and quality control in facilities like the American Type Culture Collection (ATCC) help maintain the safety of industrial strains used globally in food processing.

Category:Penicillium Category:Food microbiology Category:Industrial fungi