Bacteria in Cheese. 181 



in a limestone country, in a region full of caves, and it is 

 in these natural caves that most of the ripening is done. 

 These caverns are always very moist and have a tempera- 

 ture ranging from 35 to 44 F., so that the growth of the 

 fungus is retarded considerably. The spread of the mold 

 throughout the ripening mass is also assisted in a mechan- 

 ical way. The partially-matured cheese are run through 

 a machine that pricks them full of small holes. These 

 slender canals allow the mold organism to penetrate the 

 whole mass more thoroughly, the moldy straw matting 

 upon which the ripening cheese are placed helping to fur- 

 nish an abundant seeding of the desired germ. 



When new factories are constructed it is of advantage 

 to introduce this necessary germ in quantities, and the 

 practice is sometimes followed of rubbing the walls and 

 cellars of the new location with material taken from the 

 old established factory. In this custom, developed in purely 

 an empirical manner, is to be seen a striking illustration 

 of a bacteriological process crudely carried out. 



In the Stilton cheese, one of the highly prized moldy 

 cheeses of England, the desired mold fungus is introduced 

 into the green cheese by exchanging plugs taken with a 

 cheese trier from a ripe Stilton. 



Ripening of soft cheese. The type of ripening which 

 takes place in the soft cheeses is materially different from 

 that which occurs in the hard type. In many cases, the 

 peptoiiizing action does not go on uniformly through- 

 out the cheese, but is hastened on the exterior by the de- 

 velopment of organisms that exert a solvent effect on the 

 casein. For this reason, soft cheeses are usually made up 

 in small sizes, so that this action may be facilitated. The 

 bacteria that take part in this process are those that are 



