Diversity of Geotrichum candidum Strains Isolated from Traditional Cheesemaking Fabrications in France

Abstract

The diversity of French fungus-ripened cheeses is due partly to the succession of fungi that colonize the cheese during ripening. Geotrichum candidum appears in the early stages of ripening on soft cheeses such as Camembert and semihard cheeses such as St. Nectaire and Reblochon. Its lipases and proteases promote flavor development, and its aminopeptidases reduce bitterness imparted by low-molecular-weight peptides in cheese. We assessed the genetic diversity of G. candidum strains by using random amplification of polymorphic DNA (RAPD)-PCR correlated with phenotypic tests for carbon assimilation and salt tolerance. Strains were isolated from milk, curd, and cheese collected in seven major cheesemaking regions of France. Sixty-four isolates were characterized. We found high genetic diversity of G. candidum even within the same cheesemaking regions. Strains did not group according to region. All of the strains from the Haute-Savoie were able to assimilate lactate as the sole source of carbon, while lactate assimilation varied among strains from the Auvergne. Strains varied in D-mannitol assimilation, and none used citrate as the sole source of carbon. Yeast-like colony morphology predominated in Reblochon, while all of the strains isolated from St. Nectaire were filamentous. The RAPD-PCR technique readily differentiated Geotrichum fragrans isolated from milk and curd in a St. Nectaire cheesemaking facility. This study reveals an enormous diversity of G. candidum that has been empirically selected through the centuries by the cheesemakers of France.

Effect of temperature and lactic acid bacteria on the surface growth of Geotrichum candidum

“…When the fungus grows on the cheese surface, the white coat formation can be observed. In cheese, the overgrowth of fungus is responsible not only for changing the appearance but also for the catabolism of milk protein and fat (Marcellino et al 2001). In the dairy practice, it is important to keep the growth of G. candidum under the desired level and to control in this way the flavour development.…”

Quantification of Geotrichum candidum growth in co-culture with lactic acid bacteria

“…A role of G. candidum in food could be evaluated posi-tive but also negative. It is widely used in a milk industry as a second/adjunct culture in many soft cheeses such as Camembert, semi-fresh and semihard cheeses (Addis et al 2001;Marcellino et al 2001;Boutrou & Guéguen 2005;Pottier et al 2008). The metabolic activity of G. candidum plays an important role in the development of characteristic flavours, taste and other qualities of milk products (Marcellino et al 2001).…”

Microflora identification of fresh and fermented camel milk from Kazakhstan

“…The yeast Geotrichum candidum which was identified in our study is appearing in the early stages of ripening on soft and semi-hard French cheeses. Its lipases and proteases promote flavor development, and its aminopeptidases reduce bitterness imparted by lowmolecular-weight peptides in cheese (Marcellino et al, 2001). Njage et al (2011) also identified species belonging to the genera Rhodotorula, Cryptococcus, Candida, Trichosporon, Geotrichum and Issatchenkia which weren't founded in our study.…”