264 Milk and Its Products 
down or rendering soluble the casein and in the 
development of the characteristic flavors peculiar to 
good cheese. These flavors are almost entirely de- 
veloped during the ripening process. The ripening 
is brought about by a series of fermentations that 
goes on in the cheese. It is not well understood 
just what these fermentations are; but it seems 
evident that at least in the early stages of the 
curing, lactic acid germs are active, although the 
greater majority of these disappear after a short 
time. During the ripening process, oxygen is taken 
up and carbonic acid given off. The quality of 
the cheese is best when the ripening process goes 
on gradually and continually. The higher the tem- 
perature the faster the ripening will go on, an 
extreme temperature of 65° or 70° giving the best 
results. At the end of from four to six weeks the 
casein will be so broken down that the cheese is 
fairly digestible and fit for consumption, though if 
kept longer under good conditions the cheese will 
improve for three or four -months, and then if kept 
moderately cool, and in not too moist nor too dry 
an atmosphere, it may be kept one or two years. 
If the cheese is well made, if the whey has been 
thoroughly separated in the process of making and if 
the milk was sound and free from taints, the ripening 
process will go on regularly even at low temperatures, 
though the time required is much: longer. The result- 
ing cheese will be of the best possible flavor and tex- 
ture. The practice is now quite general to remove the 
.cheese at the age of seven to ten days at once to cold 
