232 Journal of Agricultural Research voi.xin.No.4 



organisms of the slime, as compared with the vigorous activity of the 

 Penicilliuin roqueforti suggest that in Roquefort cheese also the slime 

 organisms are of minor importance, if indeed they have any influence in 

 the cheese ripening. 



It is said that if the Penicillnim roqtieforti fails to develop, there is, 

 nevertheless, a softening of the curd after a long period of ripening. 

 In such case the ripening is undoubtedly brought about by the bac- 

 teria of the interior of the cheese, probably aided to a considerable 

 extent by the enzyms from the slime; but a ripe cheese of that kind is 

 not a typical Roquefort cheese. 



The Roquefort-cheese slime is normally of a reddish color, but no 

 organisms producing red pigment were isolated from it, although appar- 

 ently all forms seen in the smears grew in the plates. The only expla- 

 nation that can be offered is that the cocci, rod forms, and yeast cells, 

 all containing more or less yellow-and-orange pigment, may produce a 

 reddish tinge when mixed in mass. It is quite possible that the pig- 

 ment production of one or all of those species is altered by the intimate 

 association with the other species. 



SUMMARY 



The microorganisms essential for the manufacture and ripening of 

 Roquefort cheese are Streptococcus lacticus and Penicillnim roqueforti. 



Streptococcus lacticus decomposes the lactose during the manufacture 

 of the cheese and thus produces the lactic acid necessary for the cheese 

 making. These organisms disappear from the cheese after about two 

 or three weeks, being killed by the high concentration of sodium chlorid. 



The remaining flora of Roquefort cheese consists of cheese streptococci 

 and Bacterium hulgaricum, organisms which are found in all kinds of 

 ripening cheese. These organisms do not have any significant part to 

 play in the ripening of Roquefort cheese. 



The cheese slime consists of characteristic types of micrococci, rod 

 forms, and yeast cells. The enzyms from the slime do not appear to be 

 essential to the ripening of the cheese. 



The flora of both the interior and the slime of the experimental cheese 

 was identical with the flora of the interior and the slime of the imported 

 cheese. 



If the maker of Roquefort cheese will inoculate properly with Strepto- 

 coccus lacticus and Penicillium roqueforti, and provide the proper condi- 

 tion of manufacture and ripening, he need have no other concern about 

 biological ripening agents. 



