Bacterial Flora of Roquefort Cheese

It is well known that various kinds of hard cheese, such as Cheddar and Emmental, or Swiss, depend on a suitable bacterial flora for their normal development. The two types of cheese mentioned have been studied extensively by a number of investigators. It has been shown that in the manufacture of Cheddar cheese there must be a rapid development of the lactic-acid bacterium Streptococcus lacticus, and that during the ripening a development of other forms of cocci and lactic bacteria of the bulgaricum 1 type is necessary to produce the typical Cheddar flavor (4). In Swiss-cheese manufacture the Bacterium bulgaricum is added, either in pure culture, as a starter, or unwittingly, with the nennet. What other microorganisms are responsible for the characteristic sweetish flavor, and for the development of the * 'eyes"; has not yet been established, but at any rate the ripening is due to the growth of bacteria, in distinction from the mold-ripened cheeses. It is obvious that in cheeses which are mottled with molds the molds play an important part in the ripening. The mold which ripens Roquefort cheese, and also Gorgonzola and Stilton cheeses, has been named "Pénicillium roqueforti (Thorn)" (6). Currie (J) has shown that it hydrolyzes fat and the resulting acids have the peppery or burning effect on the tongue and palate which is characteristic of Roquefort cheese. In the making of Roquefort cheese, as in the making of Cheddar cheese, a rapid development of lactic-acid bacteria is necessary to bring about the proper physical condition of the curd in the various stages of manufacture. This acidity results from the growth of Streptococcus lacticus. The importance of the 5. lacticus and Pénicillium roqueforti in the making and ripening of Roquefort cheese was recognized by Thorn, who