yi6 The Use of Starters in Dairying. [dec. 



before he is in a position to supply the scientist with that very- 

 accurate information which is essential to systematic work. 

 The scientist, we know, is willing and anxious to help, and it 

 is to be hoped that he and the agriculturist together may in the 

 future even improve British pedigree stock, which to-day 

 stands, as a class, the best that the breeders of the world can 

 produce. 



THE USE OF STARTERS IN DAIRYING. 

 By John Porter, B.Sc, 



Organiser of Agricultural Education for Herefordshire. 



It is only a few years since modern methods were introduced 

 into butter and cheese-making. Previous to that the resultant 

 product was not all that could be desired. Cheese and butter 

 merchants complained that there was a great lack of uniformity 

 in the quality, with the result that they had difficulty in 

 giving satisfaction to their customers. Now, however, the 

 situation is changed. By the use of the " starter " the butter- 

 maker and cheese-maker may control the ripening of the 

 cream or the development of acidity in the cheese-making 

 process to such an extent that the production of a uniform 

 article can be accomplished. In fact, success in butter and | 

 cheese-making is only possible where the ripening process 

 or development of acidity is properly controlled. 



The Theory of Ripening. — Everyone has observed that 

 milk or cream exposed to the air soon becomes sour and 

 curdles. This development of acidity is brought about by 

 the activity of the lactic acid bacteria, which find their way 

 into the milk, live in it, feed on the milk sugar or lactose, 

 and change it into lactic acid. The lactic acid produced 

 precipitates the casein, causing the milk to curdle or thicken. 

 This development of lactic acid in milk or cream is called j 

 the "ripening process." These bacteria are susceptible to j 

 heat and cold. At very high temperatures they are killed, [ 

 while towards freezing point they cease to be active. Between j 

 these two extremes there is an optimum temperature, some- 

 where about 8o° or 90 0 Fahr., at which they develop and 

 multiply very rapidly. To hasten the ripening process, one 

 must raise the temperature of the milk or cream as near the 

 optimum as possible, while to retard it, the milk or cream 



