Abstract
Filamentous fungi play important roles in the production of a variety of cheeses. The most famous are the blue cheeses, such as Roquefort or Gorgonzola, in which Penicillium roqueforti is the principal mold, and the moldy soft cheeses, such as Camembert or Brie, in which production involves Penicillium camemberti. There are also other filamentous fungi associated with certain types of cheeses, such as Mucor spp., Trichothecium roseum, and Fusarium domesticum in Saint Nectaire, Sporendonema casei in Cantal, Salers and Rodez cheeses, Scopulariopsis species in various French and Austrian cheeses, and Mucor mucedo and Mucor racemosus in the traditional Norwegian cheese Gamalost. These fungi are either inoculated on the cheese as a starter culture or stand out in mixed cultures during spontaneous fermentation. This chapter reviews the filamentous fungi used to produce different kinds of cheeses in terms of taxonomy, physiology, ecology, and mycotoxins, and the microbiological or biochemical effects of these fungi on cheese production.
TopIntroduction
Filamentous fungi are used in the manufacture of different kinds of cheeses. The mold-ripened cheeses can be divided into two broad categories: internally ripened and surface-ripened (Figure 1). In internally ripened cheeses, mold growth is visible both on the surface and in the interior part of the cheese. The most well-known of these cheeses are the blue cheeses, which are produced in different countries under different names. For the production of blue cheeses, the main ripening agent is Penicillium roqueforti, which creates blue veins in the cheese as it grows. Another lesser-known, internally ripened variety is Norwegian Gamalost, which involves Mucor as the ripening mold that gives the cheese its characteristic flavor, texture and yellow-brown color. The second category of mold-ripened cheeses is the surface-ripened cheeses. The most famous of these are the Camembert-type soft cheeses, in which Penicillium camemberti is involved in the production as the ripening mold; the mold covers the surface and forms a white coat. There are other mold-ripened cheeses such as the semi-hard cheese Saint Nectaire, which uses Mucor spp., Trichothecium roseum and Fusarium domesticum as the ripening molds, and the hard surface-ripened cheeses such as French Cantal, Salers and Rodez, which involve Scopulariopsis species or Sporendonema casei. The sources of filamentous fungi used for the production of these cheeses can be milk when raw milk is used, or the fungi may be derived from the environment in which ripening occurs or from starter cultures directly added into the milk or curd. This chapter summarizes information on the filamentous fungi involved in the production of mold-ripened cheeses in terms of taxonomy, physiological characteristics, ecological habitats, and mycotoxins and the importance of these fungi in cheese production.
Figure 1. Classification of mold-ripened cheeses