BACTERIA IN BUTTER 197 



to twenty-five gallons of ordinary cream. This is allowed to 

 ripen as usual, and is then used as an infecting culture, or 

 " starter," in the large cream vats in the proportion of i gallon 

 of infecting culture to 25 gallons of cream, and the whole 

 is ripened at a temperature of about 68° F. for one day. The 

 cream ripened by this organism needs to be churned at a little 

 lower temperature (say S^°-SA° F.), but to be ripened at a little 

 higher temperature than ordinary cream to produce the best 

 results. Cream ripened with No. 41 has its keeping power much 

 increased, and the body or grain of the butter is not affected. But 

 it must be borne in mind that the use of starters will not make 

 good butter out of poor cream. More than 200 creameries in 

 America used this culture during 1895 ; which proves that its use 

 for the production of flavour in butter is feasible in ordinary 

 creameries and in the hands of ordinary butter-makers provided 

 they will use proper methods and discretion.^ More recently, 

 however, pasteurisation has fallen into abeyance, on account of 

 the added expense, and the use of artificial cultures is said to have 

 declined in America. Nevertheless the principles involved in the 

 cultural process have remained, and as a consequence there has 

 been increased attention paid to cleanly dairying and cream 

 ripening.- 



In England, with a few exceptions, practically nothing has been 

 done in a commercial way in the direction of artificial starters. 

 But this development elsewhere has doubtless had a beneficial 

 effect upon dairying generally, and in particular upon the teaching 

 of the various dairy colleges and institutes. For example, one of the 

 chief systems now laid down and practised with great success lays 

 stress upon the hygiene and cleanliness of cows and clean milking, 

 in order to avoid the presence of bad-flavouring bacteria in the 

 cream ripening. 



The number of bacteria in butter varies considerably accord- 

 ing to time of examination. If the butter is just made, as many 

 as thirty to fifty million organisms may be found in one 

 gramme. But if some three or four days old, from 50,000 to two 

 or three million only will be present. This marked decline is an 

 almost invariable characteristic of the bacterial content of butter. 

 Many of the cream organisms have been eliminated in the butter- 



^ See also University of Wisconsin Agricultural Expt. Sta., Twelfth 

 Annual Report, 1895, P- 174, and Bulletin No. 48, 1896. 



■^ Fifteenth Annual Report of Bureau of Animal Industry^ Washington, 

 1898, p. 85. 



