BACTERIA, IN CHEESE 253 



it is perfectly feasible with the soft cheeses. By thorough pas- 

 teurizing most of the mischievous bacteria in the milk can be 

 killed, and then, if proper lactic bacteria and mold cultures are 

 subsequently inoculated into the milk, the ripening will take 

 place normally and more uniformly. This procedure has been 

 adopted in some of the better and more scientific factories in 

 Europe, and is also being taken up in this country in the manu- 

 facture of these cheeses. The manipulation of the pasteurized 

 milk needs to be slightly different, but offers no great difficulty. 

 The second general safeguard for the cheese is the use of a 

 large amount of a vigorous lactic acid starter to hold in check 

 the growth of the organisms that would otherwise be likely to 

 produce trouble. By these two methods it will probably be pos- 

 sible to control the ripening and to avoid the irregularities that 

 have too frequently arisen. 



THE ROQUEFORT TYPE 



This type includes the Roquefort, the Stilton and the Gorgon- 

 zola cheeses. Their method of manufacture is somewhat dif- 

 ferent, but, in all cases, the essential character of the cheese 

 is produced by the growth of the same species of mold within 

 the cheese. They do not have a moldy rind and show no ex- 

 ternal evidence of the ripening agent. Anyone familiar with 

 these cheeses will remember that when ripened they are filled 

 with green masses and streaks, and microscopic study shows 

 that these are the spores of a species of mold that has been 

 named Penicillium roqucforti. (Fig. 67.) It is much like the 

 Camembert mold, only that the latter is white, while the Roque- 

 fort mold, when it produces spores, is a blue green. In the 

 ripening of the Roquefort, Stilton, etc., the molds do not grow 

 on the surface, as in the case of Camembert cheese, but they 

 grow within the cheese; and to bring this about the texture of 

 the curd is made somewhat porous, so that it contains abundant 

 air spores within, into which the mold can grow. 



